1374
Goldschmidt Conference Abstracts
Structural phase transition of
ammonia hydrate under high
pressure
Characteristic of mineral component
in carlin-type gold deposit in Qinling
area
CHUNLI MA, QIANG ZHOU, FANGFEI LI, JIAN HAO,
JINGSHU WANG, FENGXIAN HUANG AND QILIANG CUI*
State key Laboratory of Superhard Materials, Jilin University,
Changchun, 130012, P.R.China
(*correspondence: [email protected])
High pressure Raman scattering studies and angledispersive synchrotron x-ray diffraction measurements have
performed on water-ammonia binary system up to 29.92GPa
and 45.11GPa, respectively. Moreover, with pressure
increased slowly, it was found from microscope that the
appearance of lozenge blocked solid in the sample chamber at
3.48GPa. Compared with the Raman spectrum of ice and solid
ammonia, we observed that the new appeared solid was
ammonia hydrate. Hence, Raman spectrum of water-ammonia
binary system and ammonia hydrate would be obtained at
same pressure, respectively. Therefore, it was observed that
the water-ammonia binary system transformed from liquid to
solid phase at 3.8GPa but the ammonia hydrate had no phase
transition up to 20.34GPa because of the disappearance of
Raman spectrum. However, high pressure angle-dispersive
synchrotron x-ray diffraction measurements showed that there
was a solid to solid phase transition of ammonia hydrate at
about 20GPa. And the mechanism of this phase transition is in
processing.
This work was financial supported by the National Natural
Science Foundation of China (No.10574054, No.10976011
and No.11004074); the National Basic Research Program of
China (2011CB808200).
Mineralogical Magazine
MA GUANG1, GONG LI1*, DONG YUN FENG2,
CHEN KUIKUI1 AND ZHANG GUIPING3
Henan Polytechnic University, Heana 454001, China
(*correspondence: [email protected])
2
Liaoning Geological environment monitor station, Liaoning
100032, China
3
China Geological Library, Beijing, 100083
1
Introduction
The intergrowth combination of ore mineral in different
Carlin-type gold deposits in the Qinling area are roughly
consistent, and, the gold mainly forms in the first stage of the
hydrothermal period—arsenic-rich sulfide phase, Gold existed
mainly in the form of native gold with irregular granular
shape, secondly, it assumes the sub-microscopic gold existing
in the arsenic sulfide.
Experiment and Results
Gold minerals output mainly in the form of native gold
and have irregular granular primarily, also show the shape of
flake, clavate, arborization and so on. Particle size are
generally small and mostly exists as the form of microscopic
gold - sub-microscopic gold, a few may be visible to the naked
eye. Most of the sub-micro golden are located within the
arsenic-sulfide mineral (80.4%~85.2%). The major minerals
are the arsenical pyrites and arsenopyrite, in the next place are
the tennantite, the realgar, the orpiment, the stibnite and so on,
sometimes associated with the few chalcopyrite, the galena
and the sphalerite. It has the characteristic of proliferation
annulus in crystal grain interior of the arsenical pyrites,
according this, may determine the ore deposit type and the
provide effective prospecting method.
In the metallogenesis hydrothermal stage of ore deposit,
arsenic pyrite and arsenopyrite is the gold-bearing mineral
crystallized earliest and distributed widely in most deposits,
however, the arsenopyrite content change large in the different
ore deposit. Minerals above constituent uppermost stage of
gold mineralization—rich-arsenic sulfide stage, this stage has
formed the stable Au-As element combination and the mineral
association, the stibnite, the cinnabar, the realgar and the
orpiment forms late and fill in opening space with vein shape.
After rich-arsenic sulfide hydrothermal stage, appear the vein
with intense silicification, calcilized and the barite arteries, the
veins forms in the late stages of metallogenesis under
oxidation.In this stage, gold-bearing arsenic sulfide has
suffered intense oxidation and hydrolysis, submicroscopic
gold dissociating has obvious enrichment in the surface.
www.minersoc.org
Goldschmidt Conference Abstracts
Olympic Dam U-Cu-Au deposit,
Australia: New age constraints
Mine hydrochemistry evolution and
water-inrush discrimination based on
GIS: A case in Panyi
L. MA1*, X.M. WANG2 AND X.P. ZHOU1
School of Resources and Environmental Engineering, Hefei
University of Technology, Hefei 230009, China
([email protected])
2
Public Geological Survey Management Center of Anhui
Province 230001, China
1
New Method
With the increase of the coal exploitation depth, intensity,
rate and scale, coal mining has been under the serious threat of
fracture-karst groundwater [1-2]. Many studies show that
groundwater flows in fractures are nonlinear and difficult to
identify [3-8]. An alternative mothod is to make use of
groundwater hydrochemical characteristics and groundwater
temperature for discriminating the source of water-inrush.
Based on ArcSDE and Microsoft SQL Server, the spatial
database for discrimination of water-inrush source of Panyi
Coal mine was designed and established. Spatial data mining
technology was introduced and applied to the analysis of mine
groundwater. Based on Voronoi diagram and DEM methods,
the distribution rules of the hydrochemical types and the
spatial association rules of groundwater chemistry and
structure were mined from the above spatial database. The
models for water-inrush source discrimination were studied
and coupled with GIS.
Results and Discussion
Spatial data mining technology was applied to analyze the
groundwater of mine, and based on Voronoi diagram and
DEM methods the distribution rules of the chemical types of
groundwater were mined.
A GIS-based identification method of mine water-inrush
source with comprehensive information which integrated
water level, water chemical and water temperature was
proposed, and the application in Panyi Mine showed that the
method can improve the precision of discrimination.
A simple, rapid and practical GIS-based system for mine
water-inrush source rapid discrimination with comprehensive
information was developed. (Grant no: 2009HGCX0233
R. MAAS1, V. KAMENETSKY2, K. EHRIG3, S. MEFFRE2,
J. MCPHIE2 AND G. DIEMAR3
University of Melbourne, Australia, [email protected]
CODES, University of Tasmania, Hobart, Australia
3
BHP-Billiton, Adelaide, Australia
1
2
The Olympic Dam supergiant U-Cu-Au-REE deposit is
located in the Olympic Dam IOCG province of the midArchean-Proterozoic Gawler Craton, South Australia.
Mineralization is hosted in hematite-rich breccia within the
1590 Ma Roxby Downs Granite, part of the strongly
mineralized Gawler Range Volcanic LIP. Initially linked to
the GRV event, recent work supports a post-GRV, lateMesoproteroic age of mineralization. Our Sm-Nd data for
step-leached ores are similar to published whole rock data and
define an (imprecise) ~1300 Ma apparent age. This is broadly
supported by Rb-Sr isochrons for the same step-leach
fractions. !Nd and 87Sr/86Sr (at 1300 Ma) are ~-7.5 and ~0.708.
Pb isotopes in isotopically zoned pyrite from mineralized
clastic sediments and galena in the ore have common Pb
model ages which suggest sediment deposition/diagenesis and
U introduction no earlier than 1.3-1.1 Ga. These age
constraints are consistent with earlier work (ionprobe U-Pb
ages in uraninite no older than 1.4 Ga, ReOs dating of
chalcopyrite ~1.26 Ga). Evidence for post-ore disturbance is
preserved in the form of 450-550 Ma apparent ages for a stepleached sericite-rich ore (Rb-Sr) and a texturally late fluoriterich vein (Sm-Nd); the ~500 Ma apparent ages are associated
with 87Sr/86Sr = 0.715-0.722.
Extraction of unequivocal age evidence for this very
complex deposit is difficult, and all ages – previously
published and new – need to be treated with caution. For
example, Sm-Nd isotope systematics are easily modified by
local REE redistribution involving Nd-rich ‘nuggets’ of
bastnaesite and florencite. Nevertheless, the balance of
evidence now indicates a post-1590 Ma age for much of the
mineralization in the period 1.4-1.1 Ga. Metal deposition in
several stages, from the magmatic GRV event to renewed
crustal-scale fluid flow during amalgamation of Rodinia at
1.2-1.1 Ga may explain the enormous size of the deposit.
[1] Qian et al. (2006) Hydrogeol. J. 14, 1192–1205. [2] Qian
et al. (2009) Hydrogeol. J. 17, 1749–1760. [3] Zhou et al.
(2004) Int. J. Rock Mech. Min. Sci. 41, 402. [4] Qian et al.
(2005) J. Hydrol. 311, 134–142. [5] Qian et al.(2007) J.
Hydrol. 339, 206–219. [6] Qian et al. (2011) Hydrol. Process.
25, 614–622. [7] Qian et al. (2011) J. Hydrol. 399, 246–254.
[8] Chen et al.(2009) Journal of Hydrodynamics 21, 820–825.
Mineralogical Magazine
1375
www.minersoc.org
1376
Goldschmidt Conference Abstracts
Variations in atmospheric helium
isotopes
J.C. MABRY*, B. MARTY, P. BURNARD
On the origins of dissolved natural
organic matter (DNOM) in rivers and
lakes
DONALD L. MACALADY1
2
AND KATHERINE WALTON-DAY
CRPG-CNRS, 54501 Nancy, France
(*correspondence: [email protected])
The purpose of this work is to look for variations in the
isotopic helium composition in the atmosphere.
Anthropogenic activities such as oil and gas exploitation
release crustal helium, which has excess 4He compared to
atmospheric helium. This may give rise to detectable spatial
and temporal variations in the atmospheric 3He/4He [1].
These differences, if they exist, would be very small [2],
and thus require very high precision measurements. However,
high precision measurements of atmospheric helium presents a
significant analytical challenge because helium is only present
in trace quantities in the air (5.24 ppm) and there are are many
of orders of magnitude difference in the abundance of the two
isotopes (3He/4Heair = 1.38 x10-6). We are designing a method
to reliably measure 3He/4He with 2‰ or better precision.
Air samples are collected in copper tubes which are then
sealed manually at the sample site with steel clamps. Each
tube holds a volume of approximately 20 cm3. Samples
collected cover a wide range of longitudes and latitudes, with
a particular emphasis on sampling across many latitudes since
the largest spatial variation is expected to be seen in latitude.
For each measurement we purify a relatively large amount
of gas (~5-15 cm3) so that we can make many repeat analyses
of the same sample gas. We have constructed an automated
extraction line which can rapidly switch between measuring
aliquots of sample with standards. A major component of our
method features an adjustable bellows on the sample aliquot
volume that enables us to adjust the size of a sample aliquot to
precisely match the standard, eliminating biases arising from
nonlinear pressure effects in the mass spectrometer. The
measurements are made using a Helix split flight tube multicollector mass spectrometer.
At present, the measured ratios of a sample have a 1!
reproducibility of 2-3‰, which is still too large to detect
variations. We have planned several changes to further
improve the next round of measurements including installing a
quadrupole mass spectrometer to monitor the gas purification
process and the addition of a cold trap to the mass
spectrometer volume.
Colorado School of Mines, Golden, CO, USA
([email protected])
2
U.S. Geological Survey, Denver, CO USA
([email protected])
1
One of the most important characteristics of DNOM, at
least with respect to reversible chemical reactivity, is its
aromatic carbon content. The DNOM (measured as dissolved
organic carbon, DOC) that dominates most rivers and lakes is
derived primarily from land plants, including various species
of woody trees and shrubs, grasses, fungi and mosses. The
specific ultraviolet absorbance (SUVA, absorbance at 254 nm
in a 1.0 cm cell divided by DOC in mgL-1) of DNOM provides
a simple, widely applicable indication of a sample’s aromatic
content. Examination of SUVA values of water samples from
rivers and lakes, then comparison of these to SUVA values for
DNOM samples derived from precursor materials, shows little
apparent commonality. These precursor materials consist of
senescent materials from plant species common to the
catchment basins of the rivers and lakes. This paper examines
the effects of geochemical processes on the SUVA values of
natural waters and associated precursor materials in order to
develop an understanding of the primary factors affecting the
origins and aromatic content of DNOM in natural waters.
[1] Oliver et al. (1984) GCA 48, 1759–1767. [2] Sano et al.
(2010) GCA 74, 4893–4901.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Proterozoic analog ecosystem and
organic biomarkers in a Florida
sinkhole
J.L. MACALADY1*, H.L. ALBRECHT1, P.V. WELANDER2,
J.M. FULTON1, I. SCHAPERDOTH1, T.S. WHITE1,
K.H. FREEMAN1, D.K. NEWMAN3 AND R.E. SUMMONS2
Geosciences Dept., Penn State Univ., University Park, PA
16802 USA (*correspondence: [email protected])
2
Dept. EAPS, MIT, Cambridge, MA 02139 USA
3
California Inst. Technology, Pasadena, CA 91125 USA
Combined SIMS U-Pb ages and Ti-inzircon geothermometry fingerprints
long deep crustal residence in the
Archaean
JOHN MACDONALD1, JOHN WHEELER1,
KATHRYN GOODENOUGH2, SIMON HARLEY3,
QUENTIN CROWLEY4 AND ELISABETTA MARIANI1
1
Competition between oxygenic and anoxygenic
phototrophs has been proposed as a mechanism that delayed
the oxygenation of the Earth's oceans and atmosphere in the
Proterozoic [1]. Factors affecting competition among modern
phototrophs are not well understood, especially under low
oxygen conditions thought to have been prevalent in
Precambrian oceans. Little Salt Spring (Sarasota County, FL,
USA) is a brackish, sulfidic sinkhole hosting a mixed
community of oxygenic and anoxygenic phototrophs.
Groundwater vents discharge into the bottom water at 73 m
depth, and thick, purple microbial mats cover sediment
surfaces in the sunlit upper basin. 16S rRNA clones from the
mat were affiliated with Cyanobacteria and Chlorobi, with
smaller numbers of Deltaproteobacteria in sulfate-reducing
clades. Six bacteriochlorophyll e homologues and
isorenieratene reflect contributions from Chlorobi, and
abundant chlorophyll a and pheophytin a likely derive from
Cyanobacteria. Hopanoid content of the mat is high (29% of
total membrane lipids). The relative abundances of polar
hopanoids in the mat are preserved in organic-rich surface
sediments accumulating in the deep portion of the sink.
Remarkably, more than half of the hopanoids in the mat and
surface sediments have 2-methyl structures, which are
preserved in the geologic record as 2-methyl hopanes and have
been interpreted as biomarkers for Cyanobacteria. PCR
amplification of the hopanol 2-methylase (hpnP) from mat
DNA retrieved a sequence affiliated with other cyanobacterial
HpnP homologs. Ongoing work at the site is aimed at: (1) a
quantitative model of anoxygenic and oxygenic contributions
to net primary productivity and biomarker production; (2)
understanding the ecological factors that promote the coexistence of oxygenic and anoxygenic phototrophs in the mat;
and (3) describing the timescale and chemical changes
associated with diagenesis of organic biomarkers.
School of Environmental Sciences, University of Liverpool,
Liverpool, L69 3GP [email protected]
2
British Geological Survey, Edinburgh EH9 3LA
3
School of GeoSciences, University of Edinburgh, Edinburgh
EH9 3JW
4
School of Natural Sciences, Trinity College, Dublin
1
Combined SIMS U-Pb ages and Ti-in-zircon
geothermometer temperatures for a population of zircons from
Archaean gneisses indicate long deep crustal residence at
>780°C for >350Ma. This technique of having both an age
and minimum temperature for each analytical spot is a new
and direct way of showing that heat flux from the mantle to
the base of the crust was higher in the Archaean than the
present day.
The rocks are TTG gneisses from the polymetamorphic
Archaean-Palaeoproterozoic Lewisian Gneiss Complex of NW
Scotland. The analysed zircon population comprises a small
number of primary magmatic cores and a range of
metamorphic domains; CL imaging showed that the
metamorphic domains were either rims or whole crystals of
uniform CL. The metamorphic domains comprised a mix of
anatectic growth and recrystallisation textures. U-Pb data
produced a spread of ages from 2.5-2.8Ga with some ages
older than this. Tight discordance limits (+5/-2%) were
applied so only the best, most concordant age data were used.
Ti analyses were filtered to exclude those from plasticallydeformed (EBSD data) and contaminated (Ba >1ppm) zircons.
We interpret the data as TTG protolith formation around
2.8-3.0Ga followed by granulite-facies metamorphism at
2.8Ga. The studied part of the Lewisian Complex remained at
>780°C up until 2.5Ga when it was cooled, possibly by uplift
and erosion. This 300 My period of elevated temperature
contrasts with Phanerozoic crustal behaviour, in which such
high grade rocks are cooled over much shorter timescales.
[1] Johnston (2009) Proc. Nat. Acad. Sci. 106, 16925–16929.
Mineralogical Magazine
1377
www.minersoc.org
1378
Goldschmidt Conference Abstracts
Assessment of heavy metal
contamination in soils around
Chinnaeru river sub-basin, Nalgonda
District, India
Influence of interfacial water
structure on surface protonation and
ion adsorption at metal oxide surfaces
M.L. MACHESKY1*, D.J. WESOLOWSKI2, L. VLCEK2,
E. MAMONTOV2, P.R.C. KENT2, M. P"EDOTA3,
J. ROSENQVIST4, M.K. RIDLEY5, P.T. CUMMINGS6,
J.D. KUBICKI7, J.O. SOFO7, N.KUMAR7, S.N. LVOV7,
A.V. BANDURA8, P. FENTER9 AND Z. ZHANG9
G. MACHENDER2, S. YASHODA1, M.N. REDDY2 AND
P.K. GOVIL1
National Geophysical Research Institute (Council of
Scientific and Industrial Research) Uppal Road,
Hyderabad-500007, A.P., India
2
Dept. of Geology, Osmania University, Hyderabad-500007,
A.P., India
1
The concentration of heavy metals such as As, Ba, Co, Cr,
Cu, Ni, Pb, Rb, Sr, V, Y, Zn and Zr were studied in soils to
understand metal contamination due to agriculture and
geogenic activities in Chinnaeru river basin, Nalgonda district,
India. This area is affected by the geogenic fluoride
contamination. The contamination of the soils was assessed on
the basis of geoaccumulation index, enrichment factor (EF),
contamination factor and degree of contamination. Forty four
soil samples were collected from the agricultural field from
the study area from top 10-50 cm layer of soil. Soil samples
were analyzed for heavy metals by using X-ray fluorescence
spectrometer. Data revealed that, soils in the study area are
significantly contaminated, showing high level of toxic
elements than normal distribution. The ranges of concentration
of Ba (370-1710 mg/kg), Cr (8.7-543 mg/kg), Cu (7.7-96.6
mg/kg), Ni (5.4-168 mg/kg), Rb (29.6-223 mg/kg), Sr (134438 mg/kg), Zr (141.2-8232 mg/kg) and Zn (29-478 mg/kg).
The concentration of other elements was similar to the levels
in the earth’s crust or pointed to metal depletion in the soil
(EF<1). The high EFs for some heavy metals obtained in soil
samples show that there is a considerable heavy metal
pollution, which could be due to excessive use of fertilizers
and pesticides used for agricultural or may be due to geogenic
activities in the area. A contamination site poses significant
environmental hazards for terrestrial and aquatic ecosystems.
They are important sources of pollution and may results in
ecotoxicological effects on terrestrial, groundwater and
aquatic ecosystems.
Univ. of Illinois, Champaign, IL 61820, USA
(*correspondence: [email protected])
2
Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
([email protected], [email protected],
[email protected], [email protected])
3
Univ. South Bohemia, #eské Bud$jovice, Czech Republic,
370 04 ([email protected])
4
University of Leeds, Leeds LS2 9JT, UK
([email protected])
5
Texas Tech University, Lubbock, TX 79409, USA
([email protected])
6
Vanderbilt Univ., Nashville, TN 37235, USA
([email protected])
7
The Pennsylvania State Univ., University Park, PA 16802,
USA ([email protected], [email protected], [email protected],
[email protected])
8
St. Petersburg State Univ., St. Petersburg, Russia
([email protected])
9
Argonne National Laboratory, Argonne, IL 60439, USA
([email protected], [email protected])
1
The overall goal of our research is to quantitatively link
experimental and computational results to elucidate the atomic
scale structure and dynamics of aqueous solutions at metal
oxide surfaces and to link these atomistic interfacial properties
with their macroscopic manifestations. Most of our efforts
have been directed toward the isostructural oxides rutile
(TiO2) and cassitertite (SnO2). The surfaces of these oxides
(primarily the 110 face) have been probed by X-ray and
neutron scattering, second harmonic generation, pH and zeta
potential titrations, and ab initio and classical MD. In total,
these techniques reveal a fairly consistent picture of interfacial
water structure and cation binding. Directly bound water
molecules are more tightly held at the cassiterite 110 surface
than rutile 110 surface, and this difference helps account for
the observed differences in surface protonation and ion
binding exhibited by these oxides.
This research has been largely supported by the Division
of Chemical Sciences, Geosciences and Biosciences, Office of
Basic Energy Sciences, U.S. Deparment of Energy.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Sr, Nd, and Pb isotopes of basalts
along hotspot-influenced Central
Indian Ridge
S. MACHIDA1, Y. ORIHASHI2, N. NEO3, M. TANIMIZU4,
S.C. UNSWORTH5 AND K. TAMAKI6
School of Creative Science and Engineering, Waseda
University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555,
Japan ([email protected])
2
Earthquake Research Institute, the University of Tokyo
3
Faculty of Sciences, Niigata University
4
Kochi Core Center, JAMSTEC
5
National Oceanography Centre, University of Southampton
6
Graduate School of Engineering, the University of Tokyo
1
A type of distal ridge-hotspot interaction is observed
between the Central Indian Ridge (CIR) and the Réunion
hotspot. The Rodrigues, Three Magi, and Gasitao Ridges
clearly indicate topographic connection of CIR at 20°S and the
Réunion hotspot track. However, northward geochemical
enrichment of MORB along a segment of CIR at 18-20°S still
remains a contentious issue, and is explained by an inflow of
plume materials from the Réunion hotspot [1, 2] or ancient
recycling process [3]. In order to define what factor regulates
melt production along hotspot-influenced CIR, it is important
to clarify extensive distribution of the plume-related or unrelated MORB. We thus report Sr, Nd, and Pb isotopic
compositions, with geochemical data set [4] and H2O content,
of fresh quenched glasses and basalts along CIR at 15-20°S.
Variation of isotopic compositions, Ba/Nb (Ba/La, Nb/Zr),
and H2O content are interpreted by mixing of three mantle
endmembers: depleted MORB mantle (DMM); enriched
source mantle for the Rodrigues Ridge [5] and intermediate
series of the Mauritius Island [e.g. 6]; and enriched source
mantle for the Gasitao Ridge [3]. These two enriched
components are geochemically distinct from the Réunion
plume. In fact, geochemical variation of MORB doesn't relate
to the pollution of the upper mantle by the Réunion plume.
Melting of the ancient recycled plate materials with a low
melting point by the heat brought from the Réunion hotspot
regulates voluminous magma production along CIR around
19°S. These results strongly support that small-scale plumeunrelated heterogeneity widespread in upper mantle [7].
[1] J.J. Mahoney et al. (1989) JGR, 94, 4033–4052. [2] B.J.
Murton et al. (2005) G3, 6, 2004GC000798. [3] F. Nauret et
al. (2006) EPSL, 245, 137–152. [4] Y. Orihashi et al. (2009)
GCA, 73 (13) Sup. 1, A975. [5] A.N. Baxter et al. (1985)
CMP, 89, 90–101. [6] S. Nohda et al. (2005) J. Petrol. 46 (3)
505–522. [7] S. Machida et al. (2009) GCA, 73, 3028–3037.
Mineralogical Magazine
1379
A field method for the in situ
determination of excess air and
oxygen consumption in groundwater
L. MÄCHLER1*,2, M.S. BRENNWALD1 AND R. KIPFER1,3
Eawag, Swiss Federal Institute of Aquatic Science and
Technology, Duebendorf, Switzerland.
(*correspondence [email protected])
2
Institute of Geochemistry and Petrology, ETH Zürich,
Switzerland
3
Institute of Biogeochemistry and Pollutant Dynamics, ETH
Zürich, Switzerland
1
Measurements of dissolved gases play a crucial role in
studying aquatic systems in the environment. An important
example is the study of oxygen consumption in groundwater.
For its determination, the input of oxygen into the water body
must be estimated. This input not only depends on the
temperature at recharge, but also on a common phenomenon
called ''excess air'', i.e. the entrapment and dissolution of air
bubbles into the water, caused by water-table fluctuations, that
lead to an excess of dissolved gases in water relative to
solubility equilibration.
Noble gases are chemically inert and therefore ideal
tracers to study gas transport in groundwater and gasexchange mechanism at the air-water boundary. The light
noble gases (He, Ne) are sensitive indicators for excess air
formation, while the heavy noble gases (Kr, Xe) are good
proxies to reconstruct the physical conditions (i.e. temperature
and salinity) of the water body during the last gas exchange
with atmosphere. Furthermore, Ar has similar physical
properties as O2 and can be used to estimate the O2-input into
groundwater.
Common methods to measure noble-gas concentrations
are all based on sampling the water in the field and
transporting the sample to the laboratory, where the analysis is
performed. However, changes in dissolved-gas concentration,
in river-groundwater interactions, can occur within
minutes/hours and cannot be studied using the conventional
approaches for noble-gas analysis.
Therefore, we developed a membrane-inlet massspectrometric system to analyse in situ O2, He, Ar, Kr, and
CO2 concentrations in groundwater in the field. The system is
based on a commercially available quadrupole massspectrometer connected to a membrane-contactor module. We
optimized the system to a measurement cycle of about 15
minutes in order to measure gas-concentration changes in
groundwater occurring in response to river table fluctuations.
www.minersoc.org
1380
Goldschmidt Conference Abstracts
Skarn bearing clintonite from
Kuhe-Dor, Shirkuh, Yazd Province,
Iran
Natural Fe-Oxidizing Lagoon as a
pretreatment in AMD remediation
FRANCISCO MACÍAS1, CARLOS AYORA2,
MANUEL A. CARABALLO1, JOSÉ MIGUEL NIETO1
3
AND TOBIAS S. RÖTTING
Department of Geology, University of Huelva. Avda Fuerzas
Armadas s/n 21071 Huelva, Spain
2
Institute of Environmental Assessment and Water Research,
CSIC, Jordi Girona 18, E-08034 Barcelona, Spain
3
Department of Geotechnical Engineering and Geosciences,
Technical University of Catalonia UPC-Barcelona Tech,
Jordi Girona 1-3, D2-005b, E-08034 Barcelona, Spain
1
A concept called Natural Fe-Oxidizing Lagoon (NFOL)
has been developed as an AMD pretreatment to enhance the
iron oxidation and remotion processes involved in the natural
attenuation of the AMD pollution, by the recreation, at a larger
scale, of the iron terraces and pools observed in the Fe-rich
AMD systems tipically found in the Iberian Pyrite Belt, SW
Spain.
The NFOL comprises a first section formed by several
preexisting iron terraces followed by a lagoon with a capacity
of 100 m3. The AMD pretreated in the NFOL, mean flow of
1.5 L/s, displayed a pH near 3 and contains 275 mg/L Fe (99%
Fe (II)), 440 mg/L Zn, 3, 400 mg/L SO4, 250 mg/L Ca, 100
mg/L Al, 18 mg/L Mn, 5 mg/L Cu and 0.1-1 mg/L As, Pb, Cr,
Cd, Co and Ni. The NFOL was built following the
recommendations offered by Piramid Consortium (2003) [1]
according to surface area (m2) and inflow (L/s) for lagoons
and aerobic wetlands, but facing an inflow Fe concentration 5
times higher.
During the 6 months period of study, the NFOL
pretreatment oxidized an average of 65% of the inflowing Fe
(II) and precipitated a mean of 38% of total inflowing Fe.
Additionally, over 80% of As in the inflow water was
retained. Schwertmannite, subsequently aged to goethite, are
the minerals responsible for the Fe (III) and As removal. The
NFOL showed a mean Fe removal rate as high as 100
g/m2/day, this value is one order of magnitude higher than the
common standards for the efficient operation of a lagoon or an
aerobic wetland in AMD environments.
NFOL pretreatment can be considered an efficient option
to oxide and remove Fe and As prior to the treatment in the
alkaline-based passive remediation system dispersed alkaline
substrate (DAS) [2].
MOHAMMAD ALI MACKIZADEH1
2
AND BATOUL TAGHIPOUR
Department of geology, faculty of sciences, Isfahan
University, Isfahan, Iran ([email protected])
2
Department of earth sciences, faculty of sciences, Shiraz
University, Shiraz, Iran ([email protected])
1
Shirkuh skarns (Kuhe Dor) are located in Cenozoic
magmatic belt of Central Iran. There is a diorite intrusion in
lower Cretaceous limestone’s are detected:
Pyroxene – spinel – clintonite – phligopite – garnet –
vesuvianite – calcite
Kuhe Dor skarn, is characteristic with rare mineral
clintonite. Clintonite shows the transition processes from mg –
skarn to ca – skarn and is formed in geologic environment
with high X H2O, low X CO2 and depletion in SiO2. Content
mineral texture evidences show unstable boundaries when
clintonite is in contact with spinel. Such petrographic evidence
suggests the formation of clintonites at the expense of
aluminum rich phase (spinel) is taken place. Skarn formation
is started in peak temperature about 800°C.
Due to post Cretaceous intrusions, various marble-skarn
mineralization are formed in eastern Shirkuh fault zone.
Marbles are made the last zone in contact metamorphic
aureole. Marbles are characterized by following mineral
assemblages:
brucite+serpentine+forstrite+hydromagnesite+calcite+dol
omite.
The marbles are undergone to pyroxene hornfels facies
with temperature between 450°C to 600°C (p<2kb). There is
three different stages in the formation of marbles;
decarbonation, hydration and carbonation which revealed by
mineral paragenes is and textures.
[1] PIRAMID-Consortium (2003) University of Newcastle
Upon Tyne, Newcastle Upon Tyne UK. [2] Rötting et al.
(2008) Appl Geochem (2008) 23, 1660–1674.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Adsorption of Cr(VI) on hydrous
manganese oxide
A. MACLEOD* AND C.M. KORETSKY
Department of Geosciences, Western Michigan University,
Kalamazoo, MI 49008, USA
(*correspondence: [email protected])
Hexavalent chromium is used in a variety of industrial
processes. When released into the environment, it can be quite
mobile and is highly toxic. Understanding and accurately
predicting Cr(VI) speciation and transport is key to
remediating contaminated sites. Cr(VI) forms chromate
(CrO4-2) and bichromate (HCrO4-) anions in natural systems,
which adsorb to various substrates at low pH and desorb at
high pH. The goal of this study is to investigate sorption of
Cr(VI) on hydrous manganese oxide (HMO) as a function of
ionic strength, pH and pCO2.
Hydrous manganese oxide was synthesized by alkametric
titation and subsequently stored under 0 pCO2 conditions.
HMO was confirmed by XRD, and N2-BET indicated a
surface area of ~230 m2/g. Experiments were conducted by
adding 20 g/L HMO to a solution of NaNO3 (0.001, 0.01 or
0.1 M) containing 10-5 M Cr(VI). The batch solution was
titrated to an initial pH of 3, and by small additions of NaOH
was titrated upwards to pH 10 with ~10 mL aliquots drawn off
at ~0.8 pH intervals. These aliquots were further equilibrated
for 24 hrs under varying pCO2 (0, atmospheric or 2.5%), then
centrifuged and the supernatant filtered and tested for Cr(VI)
concentrations using UV-vis spectrophotometry or total Cr by
ICP-OES.
Cr(VI) sorption decreases as pH increases, from nearly
95% (0.1 M NaNO3) or 75% (0.001 M NaNO3) sorbed at pH 3
to 0% sorbed at pH > 7. Cr(VI) sorption depends strongly on
ionic strength, with ~50% of the Cr(VI) sorbed at pH~6 in
0.1 M NaNO3, compared to ~4 in 0.001 M NaNO3
experiments. In contrast, Cr(VI) sorption on HMO was nearly
identical for a given ionic strength under atmospheric
compared to elevated (2.5%) pCO2 conditions.
Future work will focus on investigating possible
competitive sorption interactions between carbonate and
chromate at pCO2 levels >5%, and on Cr(VI) adsorption under
other Cr(VI) loadings and ionic strength conditions. The data
will be used to parameterize a surface complexation model, so
that results can be readily incorporated into reactive transport
models. This will further advance our predictive
understanding of Cr(VI) mobility and speciation in natural
environments.
Fractionation of HSE in the Tonga
arc: Flux melting of a depleted source
C.G. MACPHERSON1*, C.W. DALE1, D.G. PEARSON1,2,
S.J. HAMMOND3 AND R.J. ARCULUS4
Dept. of Earth Sciences, Durham University, DH1 3LE, UK
(*correspondence: [email protected])
2
Dept. for Earth & Atmos Sci, University of Alberta,
Edmonton, Canada
3
Dept. of Earth & Environ. Sciences, Open University, UK
4
Dept. of Earth & Marine Sciences, ANU, Australia
1
Highly siderophile element concentrations (Os, Ir, Ru, Pt,
Pd, Re) have been determined for a suite of fresh, submarine
mafic lavas from the Tonga arc front and the nascent Fonualei
backarc spreading centre (FSC). The highly depleted Tongan
mantle wedge combined with a high fluid flux is thought to
have produced boninitic magmas at several arc and FSC
locations. As such, this arc system provides an opportunity to
assess the fluid mobility of PGE and to investigate the effects
of fluid-induced melting and prior melt depletion on PGE
behaviour during both mantle melting and magma evolution.
Tongan lavas display extreme fractionation of the
platinum-group PGE (P-PGE) from the iridium-group PGE (IPGE) which is inherited at source and is significantly greater
than MORB. All of the PGE display low bulk compatibility
during magma evolution, reflecting sulphide undersaturation.
Rather than source PPGE enrichment by slab fluids, the
fractionation of the PPGE from the IPGE can be explained by
relatively low-temperature yet high-degree melting of fluidfluxed depleted mantle. Prior melt depletion increases the
likelihood of complete consumption of sulphide in the source
during melting, which typically produces melts with high
concentrations of all the PGE. In the Tonga arc, however, the
high PPGE contents can be explained by the exhaustion of
sulphide liquid in the source [e.g. 1], while the retention of the
IPGE requires residual monosulphide solid solution (mss) or
platinum-group minerals. Complete sulphide exhaustion is
likely given high aggregate degrees of partial melting (%25%)
of a DMM source which is sufficiently hot to melt mss. If so,
the presence of laurite (Ru-Os-(Ir) sulphide) or IPGE alloys
may explain the retention of IPGE in the source residue.
Flux-melting investigated here and a previously proposed
PGE flux from the slab indicate that subduction zones are
undoubtedly an environment where significant fractionation of
Re and Pt from Os occurs, further indicating that the core
contribution hypothesis to explain the coupled enrichments of
186
Os and 187Os may be non-unique.
[1] Mungall et al. (2005) GCA 69(17), 4349–4360.
Mineralogical Magazine
1381
www.minersoc.org
Goldschmidt Conference Abstracts
1382
New insights into San Carlos mantle
xenoliths using iron isotopes
C.A. MACRIS1*, E.D.YOUNG1,2,
C.E. MANNING1 AND E.A. SCHAUBLE1
Department of Earth and Space Sciences, UCLA, CA
(*correspondence: [email protected])
2
Institute of Geophysics and Planetary Physics, UCLA, CA
Soluble Mn(III), Mn(II) and total Mn
in sediment porewaters: Soluble
Mn(III) is ubiquitous
ANDREW S. MADISON1, ALFONSO MUCCI2,
BJØRN SUNDBY2, BRADLEY M. TEBO3
1
AND GEORGE W. LUTHER, III *
1
Iron isotopic compositions of mantle minerals can provide
powerful tracers for geochemical processes in the mantle, such
as partial melting, metasomatism, and oxidation. Predictions
of equilibrium fractionation from theory and Mössbauer data
conflict, making the meaning of Fe isotope fractionation in the
mantle uncertain. To address this, we studied inter-mineral
iron isotopic fractionation of minerals from five distinct
mantle-xenolith lithologies from San Carlos, Arizona. The
samples represent a broad range of mineral modes and include
a clinopyroxenite, a websterite, a lherzolite, a harzburgite, and
a dunite. All samples except for the websterite are Group I
inclusions, which are typically rich in Mg and Cr, and consist
of mainly olivine-rich rocks. Group II inclusions, represented
here by the websterite, are enriched in Al and Ti, and
commonly contain more clinopyroxene than orthopyroxene
[1]. Each xenolith exhibits Fe-isotopic variation between
minerals in a single sample, and between samples. In all cases
where spinel and olivine coexist in a sample, the 57Fe/54Fe of
spinel is greater than that of the corresponding olivine,
agreeing with predictions of equilibrium fractionation from
theory. 57Fe/54Fe values of clinopyroxenes and orthopyroxenes
from the xenoliths show no clear systematic differences. Plots
of "57Fe of the pyroxenes versus "57Fe of the other minerals
show that the pyroxenes underwent some open-system
processes and are not in equilibrium with the coexisting
olivine and spinel. We interpret this as a result of varying
degrees of disequilibration in the samples due to late stage
open-system processes, such as metasomatism or partial
melting, affecting the pyroxenes only. A strongly linear
reverse correlation between olivine content and bulk rock
57
Fe/54Fe was found for all samples except the websterite (the
only type II xenolith measured). The strong linear relationship
among Group I samples, and deviation from the trend in
websterite, suggests Fe isotope systematics can be added to
the list of differences used to distinguish between Group I and
Group II xenoliths.
School of Marine Science and Policy, College of Earth,
Ocean and Environment, University of Delaware, Lewes,
DE 19958, USA (*correspondence: [email protected])
([email protected])
2
Department of Earth and Planetary Sciences, McGill
University, Montreal, QC., Canada H3A 2A7
([email protected], [email protected])
3
Division of Environmental and Biomolecular Systems,
Oregon Health and Science University, Beaverton, OR
97006, USA ([email protected])
1
Recent research shows that soluble manganese(III) or
[Mn(III)]aq, that material which passes through a 0.2 µm filter,
exists in natural waters such as the Black Sea, the Baltic Sea
and Chesapeake Bay and can constitute a large fraction of the
dissolved Mn pool at the oxic/anoxic interface. Recently
Madison et al. [1] have reported a direct and accurate
spectrophotometric method to measure [Mn(III)]aq in sediment
porewaters. The method is capable of rapid and simultaneous
determination of [Mn(III)]aq, [Mn(II)]aq, and total soluble Mn.
This method was successfully applied to the determination of
all soluble Mn species in sediment porewaters of the Lower St.
Lawrence Estuary collected during cruises in 2009 and 2010
and in Delaware salt marsh sediments. In all samples,
[Mn(III)]aq accounts for up to 80% of the total dissolved Mn
pool in the upper oxic and suboxic sediments with
concentrations ranging from the detection limit of 50 nM to 80
µM. Data will be presented that highlight the role [Mn(III)]aq
plays in Mn cycling and how it can impact several important
geochemical cycles.
[1] A.S. Madison, B. M. Tebo, G. W. Luther, III. (2011)
Talanta 84, 374–381.
[1] Frey & Prinz 1978 EPSL 38, 129–176.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
He and Ne isotopic ratios from the
Terceira Rift (Azores): Constraints
on the boundary between Eurasia
and Nubia mantle sources
PEDRO MADUREIRA , MANUEL MOREIRA ,
JOÃO CARLOS NUNES3, NUNO LOURENÇO4,
CÉCILE GAUTHERON5, ROSÁRIO CARVALHO6,
JOÃO MATA6 AND MANUEL PINTO DE ABREU4
1,4
2
Univ. Évora, CGE, Dep. Geociências, Rua Romão Ramalho,
59, 7000-671 Évora, Portugal ([email protected])
2
Equipe de Géochimie et Cosmochimie, IPGP, Sorbonne Paris
Cité, CNRS (UMR 7154), 1 rue Jussieu, 75238 Paris
Cedex, France ([email protected])
3
Univ. dos Açores, Dep. Geociências, R. Mãe de Deus,
Apartado 1422, 9501-801 Ponta Delgada, Açores,
Portugal ([email protected])
4
EMAM, Rua Costa Pinto, 165, 2770-047 Paço d’Arcos,
Portugal ([email protected], [email protected])
5
UMR Interactions et Dynamique des Environnements de
Surface-CNRS 8148, Université Paris Sud, 91405 Orsay,
France ([email protected])
6
Univ. Lisboa, Faculdade de Ciências, Dep. Geologia
(GeoFCUL), CeGUL, Edifício C6, Campo Grande, 1749016, Lisboa, Portugal ([email protected],
[email protected])
1
We present He and Ne isotopic data from subaerial and
submarine samples collected along the Terceira Rift. Graciosa
Island as well as the western end of S. Miguel Island and D.
João de Castro Bank display 4He/3He ratios similar to those
observed along the MAR segments located to the north of the
Azores Triple Junction area. Conversely, samples from the
south Hirondelle Basin display a 4He/3He ratio similar to that
of the MAR segments located to the south of the Azores
Plateau. The Terceira Rift is thus characterized by the
mingling of two different mantle domains referred as ‘Eurasia’
and ‘Nubia’ type. He and Ne systematics shows that the
influence of the relatively primitive source sampled by the
Azores plume can be followed along the Terceira Rift from
the Graciosa Island towards the south Hirondelle Basin.
Moreover, samples from the south Hirondelle Basin, D. João
de Castro Bank and Graciosa Island cannot be explained by
the same hyperbolic mixing model that encloses Terceira data.
Mineralogical Magazine
1383
SHRIMP studies of the uranium
oxide-based U/Pb SIMS calibration
C.W. MAGEE
Australian Scientific Instruments 111/113 Gladstone St.
Fyshwick ACT 2609 Australia ([email protected])
Since the earliest days of SIMS U/Pb geochronology, it
has been necessary to correct for variations in the relative
ionization efficiency of Pb and U. Extensive research during
the twentieth century has resulted in the empirical derivation
of calibration cures based on observed relationships between
Pb/U and UOx/U, where x is equal to 1 or 2. This calibration is
the precision-limiting step in SIMS U-Pb data reduction.
Both oxygen activity and secondary ion energy have been
proposed asmachanisms for measured Pb/U variation. For
example, the extreme sensitivity of Pb ionization to oxygen
flooding in some SIMS instruments suggests that oxygen
activity at the sample surface may important to relative Pb and
U ionization. As is shown in figure 1, this is consistent with
the ability to use a variety of Zr, Hf, Th, or U oxide pairs as a
rough calibration, with about ~3% accuracy and precision.
Figure 1: Arbitrary oxide calibration of SHRIMP U/Pb data.
This and similar Hf and Th-based calibrations yield less
scatter than raw Pb/U or Pb/UO2.
Additional effects beyond fO2 must be responsible for the
superior performance of UOx based calibrations compared to
randomly selected metal oxide pairs. While the effect of
secondary ion energy has been discussed previously, the effect
of primary ion energy is less well studied. Primary energies as
low is 2.5kV have been investigated to determine the change
in calibration due to changes in Pb ionization efficiency,
secondary ion energy dispersion, and uranium oxide
speciation.
www.minersoc.org
1384
Goldschmidt Conference Abstracts
Reconstructing ancient landscapes:
Molecular insights to spatial patterns
in ecosystems and water
CLAYTON R. MAGILL1*, GAIL M ASHLEY2
1
AND KATHERINE H. FREEMAN
Pennsylvania State University, University Park PA 16802
(*correspondence: [email protected])
2
Rutgers University, Piscataway NJ 08854
1
Water shapes vegetation and natural landscapes at
different spatial and temporal scales – defining habitats,
selective pressures and the evolution of fauna. Hydroclimate
may have catalyzed morphologic and behavioural adaptations
in early humans through changing spatial patterns in
ecosystem structure. These can be evaluated using molecular
and isotopic ‘landscape biomarkers’ lending insights to
ancient habitats and providing means to test links between
evolution and environment. We apply these to landscapes at
spatial scales of human habitation (~1 km2) from paleosol and
lake deposits at Olduvai Gorge (ca. 1.845 million years ago).
Biomarker signatures reveal heterogeneity in sources and
composition of sedimentary organic matter. Near to a
freshwater spring (tufa) deposit, algae (heptadecane [nC17])
and sedge (n-alkylresorcinol [nAR]) biomarkers are associated
with positive ratios between the lignin monomers syringic
acid/vanillic acid (S/V) and p-coumaric acid/vanillic acid
(C/V). In contrast, sediments associated with early human
remains contain nominal nC17, nAR and C/V, instead showing
high plant-wax (hentriacontane [nC31]) abundances. Plant-wax
biomarkers &13C values range nearly 14‰ across the 1 km
paleosol transect, between sediments associated with early
human remains (-33.0‰) and grass phytoliths (-19.3‰).
Our data indicate pronounced heterogeneity in this early
human habitat, consistent with geochemical and faunal data.1
Near the spring deposit, biomarkers suggest a shallow wetland
environment with emergent vegetation. Nearby, depleted
"13C31 values and nominal C/V indicate a shrubby or wooded
environment. This area is proximal to sites with "13C31 and
C/V ratios that indicate grassland. This study focuses on a
time slice with dominant grassland (C4) signals captured in
lake sediments. In this dry time, woody and wetland
vegetation drew early humans2 to their resources.
[1] Dominguez-Rodrigo et al. (2010) Quat. Res. 74, 315–332.
[2] Blumenschine et al. (2002) Science 299, 1217–1220.
Mineralogical Magazine
Lithium – Light metallic traveller
through crusts of the Earth and
beyond
TOMÁ' MAGNA1,2
Universität Münster, Germany
([email protected])
2
Czech Geological Survey, Prague, Czech Republic
([email protected])
1
Lithium isotopes have become an increasingly used tool
for unraveling metasomatic processes in the mantle, extent and
duration of fluid transfer in subduction settings or alteration of
oceanic crust, for example. Only recently have Li isotopes
been employed to study the magmatic evolution,
metamorphism, alteration and weathering of continental crust.
This is rather surprising considering the large economic
potential of Li deposited in the crust and its utility in modern
technologies. Available data suggest a dominant control of
protolith heterogeneities and modal mineralogy for bulk
terrestrial crust, superimposed on long-term secular evolution
of Li in the continental crust as a response to weathering and
recycling through subduction zones.
For the Moon, the limited dataset for highland crust shows
a dramatic difference between mafic lower crust and calcic
plagioclase-dominated rocks of the upper anorthositic layer,
with the latter showing extreme net Li depletions coupled with
high "7Li that extends far beyond the range of mare basalts.
Whether plagioclase segregation from lunar magma ocean
exerts a major control on crust–mantle Li isotope fractionation
remains to be investigated.
That as yet unsampled evolved (crustal?) reservoirs may
exist on Mars can be deduced from the nakhlite lava sequence
as well as from two distinctive lithologies found in Zagami
and having different Li (and also Ca) systematics. Yet, this
finding is still consistent with linear Li-"7Li relationship recorded for the enriched shergotittes, thought to contain larger
proportion of evolved crustal material among shergottites.
These data point toward a low-Li high-"7Li reservoir that may
have once existed early in Martian history. On the contrary,
bulk Martian crust appears basalt-andesitic in composition,
leaving granitic rocks subordinate although, on Earth, granitic
rocks develop distinctive Li fingerprints as a consequence of
complete geological cycles. This applies perhaps to 4 Vesta
too despite local exposures of highly evolved terrains.
It may well be that juvenile crust in general develops a
uniform Li isotope signature as observed in Iceland, for
example, with invariant "7Li over a large range of chemical
compositions. Only with ample time would Li become
enriched and fractionated in the crust relative to the mantle on
a planetary scale.
www.minersoc.org
Goldschmidt Conference Abstracts
Lithium isotope composition of lunar
crust – Rapid crystallization and
post-solidification quiescence?
Surface and subsurface geochemical
monitoring of an EOR-CO2 field:
Buracica, Brazil
TOMÁ' MAGNA1,2 AND CLIVE R. NEAL3
Universität Münster, Germany
([email protected])
2
Czech Geological Survey, Prague, Czech Republic
3
University of Notre Dame, USA
C. MAGNIER1, V. ROUCHON1, C. BANDEIRA2,
R. GONÇALVES2, D. MILLER2 AND R. DINO2
1
Lunar crust consists of ferroan anorthosites (~80%) and
Mg-rich suite lithologies (~20%). It represents products from
the most ancient lunar magmatic events (>4.1 Gyr [1]) and is
accepted to have formed through plagioclase flotation on the
lunar magma ocean (LMO) [2], from which significant
amounts of incompatible elements (e.g. K, Th and U) were
concentrated in the residual LMO melt (KREEP). Lithium has
received little attention [3–6] despite its utility in tracking the
history of the terrestrial crust [7–9].
New Li data show that anorthosites are the most Li-depleted lunar material known to date with <1 ppm in pristine samples. This is consistent with [6] and opposite to Earth's continental crust [7, 8] and may in part be explained by limited Li
partitioning into plagioclase (Kdplg-melt ~0.2, [10]) from progressively crystallizing LMO for which ~3–4 ppm Li would
thus be estimated. This appears higher than Li content of the
Earth's mantle [3, 4]; the nature of such a difference is currently unclear but it could perhaps reflect a lack of net Li depletion before the accretion of the Moon [11]. Anorthosites show
uniformly high "7Li>5.7‰ (up to 9.4‰), distinct from mare
basalts [3–5] as well as the Earth's continental crust [7, 8].
"7Li of norite 77215 with a KREEP affinity is resolved from
other KREEP-rich lithologies [5]. The tight positive
correlation of "7Li with Na across the whole suite may reflect
fractional crystallization of clinopyroxene appearing on the
liquidus shortly after plagioclase during LMO crystallization.
Overall, the Li data suggest (i) rapid plagioclase segregation
without further re-equilibration with remaining LMO (through
equilibrium Li isotope fractionation) and (ii) little subsequent
modification of the lunar crust without an influence from
younger magmatic events.
[1] Wieczorek et al. (2006) RiMG 60, 221–364. [2] Taylor &
Jake! (1974) LPSC V, 1287–1305. [3] Magna et al. (2006)
EPSL 243, 336–353. [4] Seitz et al. (2006) EPSL 245, 6–18.
[5] Magna et al. (2009) GCA 73, A816. [6] Steele et al. (1980)
LPSC XI, 571–590. [7] Teng et al. (2004) GCA 68, 4167–
4178. [8] Magna et al. (2010) ChG 274, 94–107. [9] Ushikubo
et al. (2008) EPSL 272, 666–676. [10] Bindeman et al. (1998)
GCA 62, 1175–1193. [11] Magna et al. (2011) GCA 75, 2137–
2158
Mineralogical Magazine
1385
IFP Énergies nouvelles,1-4 avenue du bois Préau, 92852
Rueil Malmaison, France ([email protected])
2
PETROBRAS-CENPES/PDEXP Rua Horácio Macedo n.950,
Cidade Universitária, Ilha do Fundão, Rio de Janeiro,
Brasil, 21941-915
1
We present a surface and subsurface geochemical survey
of the Buracica EOR-CO2 field on-shore Brazil. A
methodology coupling the stable isotopes of carbon with the
noble gases was adopted to investigate the adequacy of a
geochemical monitoring to track deep fluid leakage at the
surface, with a scope of future application in the developping
CCS industry. Three campaigns of CO2 flux and concentration
in soils were performed to understand the CO2 variability
across the field. The distribution of the CO2 soil contents
between 0.8 to 14 % is correlated with the proprieties of the
soil, with a first order topographic control. These results,
together with a "13CCO2 between -15 and -23 ‰, suggest that
the bulk of the soil CO2 flux at Buracica is biological.
The gas injected and produced at numerous wells across
the field showed a great spatial and somewhat temporal
heterogeneity with respect to molecular, "13CCO2 and noble gas
compositions. The injected CO2 is characterized by "13CCO2
near -31 ‰ and a peculiar noble gas composition enriched in
Kr with respect to atmospheric values, while being depleted in
the lighter noble gases. The heterogeneity of the gas produced
from the reservoir is a consequence of the EOR-induced
sweeping of the indigenous fluids by the injected CO2,
producing a heterogeneous mixing controlled by 1) the
production scheme and 2) the distribution in reservoir
permeability. In the light of the "13CCO2 found in the reservoir
(from -36 to +6 ‰), the stable isotopic composition of carbon
revealed insufficient to track CO2 leaks at the surface. We
demonstrate how noble gases may be powerful leak
discriminators, even for CO2 abundances in soils in the bottom
range of the biological baseline (~1 %). The results presented
in this study show the potentiality of geochemical monitoring
techniques, involving stable isotopes and noble gases at the
reservoir and soil levels, for tracing CO2 in CCS and EOR
projects.
www.minersoc.org
Goldschmidt Conference Abstracts
1386
Geology and mineralogy of
Bidakhavid indusrial soil
A. MAHDAVI AND B. TAGHIPOUR
Department of earth sciences, student of sciences, shiraz
university, shiraz, Iran ([email protected],
[email protected])
Bidakhavid industrial soil is located 70 km southwester of
ayzd city, central Iran. this area is a part of Cenozoeic
magmatic belt. According the geological map of geology
survey of Iran (1:250000 map of Yazd, Iran).
Bidakhavide feldspar mine is near the Shir-Kuh massive
intrusion and Jamal limestone formation with Jurassic age,
Darreh-Zereshk is the main fault in this area.
Petrologicaly, predominant rock is sandstone in this area.
with attention the Folk classification this sandstones are
including: litarenite, arkosic arenite, arenite and sublitarenite.
Quartz, alkali-feldspar and jarosite are the main minerals and
biotite, muscovite and hematite are minor minerals.
X-ray diffractometery results show, quartz, albite, orthoclase,
jarosite and clay minerals are the main minerals in the
Biakhavid sandstones (Fig. 1).
Figure 1: sample figures of XRD diagram
Because of weak roundness structure and poorly sorted of
sandstones grain it is obvious that, parent rock is near the
Biakhavid mine. According to fild evidence, petrography and
mineralogy studies sandstones composition is similar to the
Shir-Kuh granite. So we can conclude that Shi-kuh intrusion
has an important role for the providing of primary material for
the industrial soil in the Biakhavid area. Also it must be noted
that Darreh-Zereshk fault movements may have supported
fluids for alteration of Shir-Kuh granite.
The role of fluid residence times in
controlling the chemical fluxes and
isotopic compositions of rivers
K. MAHER*, A. SCHNEIDER-MOR AND J.L. OSTER
Dept. of Geological and Environmental Sciences, Stanford
University, Stanford, CA, 94305, USA
(*correspondence: [email protected])
The role of fluid residence times and catchment length
scales in controlling the chemical composition of rivers is
evaluated by comparing numerical simulations and scaling
arguments to concentration-discharge data from small
catchments and global rivers. The analysis suggests that the
actual residence time of fluid relative to the residence time
required to approach chemical equilibrium is likely a
dominant control on solute fluxes. Catchments that show little
variability in concentration with discharge (or ‘chemostatic
behavior’) likely have average fluid residence times that
exceed the time required to reach chemical equilibrium.
Conversely, decreases in concentration with increasing
discharge are explained by average residence times shorter
than required to approach equilibrium, resulting in dilution.
Increases in runoff associated with climate change can result
in either a proportional increase in weathering fluxes, or a
plateau in weathering fluxes if the fluid residence times
become shorter than the time required for equilibrium. The
same theoretical considerations can be applied to interpret the
behavior of Sr and U isotopes in rivers. The extent of isotopic
equilibrium and the final isotopic composition reflected by
river waters will also depend on the ratio of the fluid residence
time to the time required to reach isotopic equilibrium, where
the later varies widely across isotopic systems and weathering
environments.
This framework also has implications for weathering rates
in the past. As a consequence of the thermodynamic and
hydrologic restrictions on the amount of weathering outlined
above, global solute fluxes may depend more strongly on the
geometry, relief, runoff and permeability of basins then on
temperature and rates of erosion. If fluid residence times and
catchment length scales are a dominant control on weathering
fluxes, the chemistry and isotopic composition of different
rivers could vary entirely as a function of the nature
subsurface flow paths and the composition of the system at
chemical equilibrium, which is complex to predict and
strongly coupled to biological processes.
[1] 1:250000 map of Yazd, Iran. [2] Folk R.L. (1965)
Petrology of Sedimentary Rocks, Hemphill.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Latitudinal changes in sea surface
temperature and salinity over the
Eastern Arabian Sea during the Last
Glacial Maximum through Holocene
B.S. MAHESH* AND V.K. BANAKAR
National Institute of Oceanography (CSIR), Goa, India.
(*correspondence: [email protected])
Three sediment cores dated by radiocarbon spanning the
last ~35 kyr have been utilized to reconstruct the past
hydrography in the Eastern Arabian Sea (EAS). These three
sediment cores were collected in a North-South transect where
significant hydrographic differences occur between their
locations. The EAS receives significant amount of overhead
precipitation as it borders the orographic barrier all along the
western margin of peninsular India due to Deccan Mountains.
As a result the sea surface temperature (SST) and surface
salinity (salinity) in the EAS respond to subtle changes in the
intensity of the monsoons. Here we reconstruct the SST and
salinity from by the paired measurement of "18O and SST
utilizing Globigerinoides sacculifer, an upper mixed layer
dwelling foraminifera. The last glacial maximum (LGM)
could be defined as the heaviest "18OG.sacculifer (-0.07±0.08‰)
and is evident between 23 – 15 ka BP. The "18OG.sacculifer shift
between the LGM and Holocene in all the three sediment
cores is ~ 2‰. The SSTs show an overall warming of 2°C
from the LGM to Holocene (28°C to 30°C). However, coldest
SSTs are observed prior to LGM (~27 ka BP) in all the three
records. The salinity is higher (~ 38 psu) throughout most of
the last glacial period (32.5 – 15 ka BP) compared to the
salinity during the Holocene (~36 psu). During the LGM, the
North-South salinity gradient was higher than that of modern
gradient. The increased North-South salinity gradient during
LGM may suggest not only reduced summer monsoons but
also relatively intensified winter monsoons. The higher
salinity together with generally lower SSTs indicates sustained
weaker summer or stronger winter monsoons. The deglacial
warming is associated with rapid reorganization of monsoons
and is reflected in decreased salinity to a modern level of
~ 36.5 psu within a period of ~ 5 kyr, which indicates process
of intensification of summer monsoons during cold to warm
climate transition.
Adsorption behaviour of copper in
natural composite sedimentary
materials
FLÁVIA MAIA* AND MÁRIO A. GONÇALVES
Dep. Geologia and CREMINER/LA-ISR, Fac. Ciências da
Universidade de Lisboa, Campo Grande, 1749-016,
Lisboa, Portugal,
(*correspondence: [email protected])
The understanding of adsorption processes is important
both to evaluate the potential hazard related to contaminants as
well as to minimize their impact on the environment. The aim
of this work is to carry out comprehensive adsorption
experiments using composite natural materials corresponding
to matrices of continental alluvial deposits (so called raña
deposits) from Macedo de Cavaleiros in the NE of Portugal.
These materials were considered to evaluate their capacity for
the attenuation of metal dispersion, as well as for the retention
of low to intermediate level radioactive waste. The main
minerals present in the matrices include quartz,
montmorillonite, illite and kaolinite, with abundant poorly
crystallized iron oxyhydroxides. The matrices also contain
substantial amounts of organic matter.
A protocol was developed to characterise the adsorption
behaviour of copper onto the main constituents of the natural
matrices (clay minerals, organic matter, and iron
oxyhydroxides). They were designed as to reflect the removal
efficiency of copper by the various constituents while
maintaining the structural integrity of the clay minerals.
The adsorption behaviour of copper has been evaluated by
carrying out batch experiments with Cu2+! on a series of
samples without previous treatment, removal of organic
matter, removal of Fe oxyhydroxides, and removal of both
organic matter and Fe oxyhydroxides in a range of pH
between 4 and 6.
The results show that the adsorption capacity of these
materials is rather limitted but slightly enhanced as the pH
gets higher. However, the pre-treatments had some influence
on the enhancement of the adsorption results, especially Fe
oxyhydroxides and organic matter. The low equilibrium pH of
these samples was shown to be derived from the presence of
organic matter which on itself is also likely to alter the
adsorption capacity of these matrices.
Contribution of Project KADRWaste
GEX/82678/2006 funded by FCT (Portugal)
Mineralogical Magazine
1387
www.minersoc.org
PTDC/CTE-
1388
Goldschmidt Conference Abstracts
Ptychography: A powerful X-ray
imaging tool
A.M. MAIDEN1*, G.R. MORRISON2, B. KAULICH3,
A. GIANONCELLI3, G. KAKONYI1 AND J.M. RODENBURG1
Kroto Research Institute, University of Sheffield,
Broad Lane, Sheffield, S3 7HQ, UK
(*correspondence: [email protected])
2
King’s College London, Dept. of Physics, Strand, London,
WC2R 2LS, UK ([email protected])
3
ELETTRA, S.S. 14, km 163.5 in Area Science Park, I-34012
Trieste, Italy (burkhard.kaulich /
[email protected])
1
Ptychography is a form of diffractive imaging in which
overlapping regions of a specimen are illuminated by coherent
radiation, the resulting scatter patterns recorded, and an image
formed using iterative algorithms [1, 2]. The method is
currently undergoing a renaissance as a tool for X-ray imaging
[3, 4], since its genesis as an electron microscopy technique in
the late 1960s.
The principal benefit of ptychography is its experimental
simplicity: no focussing optics are required in a ptychographic
experiment, with resolution being limited only by the angular
width of the recorded scatter patterns. Despite being
successfully demonstrated only recently in the X-ray regime,
ptychographic imaging has advanced to a stage where sub
50nm resolution is obtainable using hard X-rays [5].
Ptychography also produces quantitative phase images that in
the x-ray regime can be used to measure electron densities
accurately. By varying the beam energy ptychography can
provide chemical contrast and it can be combined very
effectively with tomography to produce three-dimensional
images [6].
Here we will introduce the ptychographic method and
describe how it works. We will discuss the merits and
drawbacks of the technique relative to more established
methods such as Scanning Transmission X-ray Microscopy
(STXM), and we will present results from recent soft X-ray
experiments at the ELETTRA synchrotron in Trieste, where
ptychography was used to image iron nanoparticles within
cells.
[1] Rodenburg (2008) Advances in Imaging & Electron
Physics 150, 87–182. [2] Maiden (2009) Ultramicroscopy
109, 1256–1262. [3] Thibault (2008) Science 321 378–382.
[4] Giewekemeyer (2011) Optics Express 19, 1037–1050.
[5] Schropp (2011) J. of Microsc. 241, 9-12. [6] Dierolf
(2010) Nature 467, 436-439.
Mineralogical Magazine
Detailed field relations of pre-3.85 Ga
zircon bearing metasediments from
southern Montana (USA)
A.C. MAIER*, N.L. CATES AND S.J. MOJZSIS
University of Colorado, Department of Geological Sciences,
2200 Colorado Avenue, Boulder, CO 80309-0399 USA
(*correspondence: [email protected])
Paleoarchean fuchsitic detrital quartzites in the
Bearthtooth Mountains (Wyoming craton, southern Montana,
USA) are one of the few documented localities that host
Hadean (>3.85 Ga) detrital zircons [1]. Our high-resolution
mapping (1:250) revealed several other rock-types in the area
that include intrusive granitoids and mafic dikes, banded ironformation (BIF), paragneisses, and a possible metaconglomerate. Zircon geochronology from quartzites and
paragneisses [1; this study] reveals several age populations:
>3.6-4.0 Ga; 3.4-3.6 Ga; 3.2-3.3 Ga; 3.0-3.1 Ga; and 2.7-2.8
Ga. Some of these are coincident with known metamorphic
events [2] responsible for discordant ages seen in much of the
data. We find that there is no obvious correlation between
degree of discordance and zircon-bearing lithology.
Zirconiferous quartzites are Cr- (40-360 ppm) and SiO2(93-95 wt.%) rich with low Zr (37-81 ppm). Paragneisses
resemble the quartzites (Cr: 230 ppm), but with less SiO2 (75
wt.%) and more Al2O3 (14 wt.%) and high Zr (348 ppm);
paragneisses and quartzites follow expected weathering trends
for a mixed granitoid + mafic source [3]. A candidate
conglomerate (SiO2 77 wt.%; Al2O3 14 wt.%) and (intrusive)
granitoids (SiO2 73 wt.%; Al2O3 15 wt.%) resemble the
paragneisses, but the conglomerate has 70 ppm Cr and 49 ppm
Zr, whereas the intrusive felsite body is Cr-poor (<D.L.), with
typical orthogneissic Zr (167 ppm). The BIF is Fe2O3-rich (51
wt.%) with low SiO2 (44 wt.%) and minor Al2O3 (3 wt.%), Cr
(50 ppm) and Zr (26 ppm) pointing to a detrital component;
multi-element plots compared to other BIFs and normalized to
NASC shows a similar positive slope, but with no Eu anomaly
and low (but still superchondritic) Y/Ho (28.7). In PMnormalized spider diagrams, detrital and igneous ‘felsic’
lithologies show enriched LILE, negative Nb anomalies, with
depletions in Sr and Ti.
Ancient detrital/xenocrystic zircons confirm that older
crustal components existed in the area, suggestive of a genetic
link between the Beartooth quartzites and the geology of the
Western Slave Province [1] and perhaps the Thelon Basin in
Nunavut [3] and the Assean Lake Complex (Manitoba; [4]).
[1] Mueller et al. (1992) Geology 20, 327–330. [2] Mueller et
al. (1998) Precamb. Res. 91, 295–307 [3] Palmer et al. (2004)
Precamb. Res. 129, 115–140. [4] Böhm et al. (2000) Geology
28, 75–78.
www.minersoc.org
Goldschmidt Conference Abstracts
Gold contents of the cratonic subcontinental lithospheric mantle:
Implications for orogenic gold
deposits
W.D. MAIER1*, A KONTINEN2 AND I. MCDONALD3
University of Oulu, Oulu, 90014, Finland
(*correspondence: [email protected])
2
Geological Survey of Finland, Kuopio, 70211, Finland
3
Cardiff University, Cardiff, CF10 3YE, Uk
1
The occurence of many orogenic gold deposits within
Archaean cratons suggests that the gold could be sourced from
the sub-cratonic lithospheric mantle. The model has been
difficult to test because the available cratonic mantle samples
consist almost entirely of kimberlite-borne xenoliths, few of
which have been analysed for Au. Furthermore, Au levels in
mantle rocks tend to be close to the detection limit of current
analytical methods. In the present study we have determined
Au contents in 81 kimberlite borne peridotite and MARID
mantle samples from the southern Africa, using ICP-MS after
Ni-sulfide fire assay and Te co-precipitation at Cardiff
University. The blank contained 0.11±0.03Au, resulting in a
procedural detection limit of 0.1 ppb Au and a quantification
limit of 0.33 ppb Au. On average, the Kaapvaal xenoliths
contain 1.09 ppb Au, broadly in the range of primitive upper
mantle estimates. In order to exclude the possibility that the
xenoliths could be non-representative of the SCLM we have
also analysed Au in 24 samples of the Jormua massif in
Finland, interpreted to represent Archean cratonic SCLM that
was obducted onto the Karelian craton margin at ca 1.95 Ga.
The average Au content of 23 Jormua samples is 1.01 ppb,
with one additional highly talc-carbonate replaced sample
containing more than 100 ppb Au.
Our samples, as well as many other samples from noncratonic lithospheric mantle, show high primitive-mantle
normalized Au/Pd ratios, due to pervasive Pd depletion.
We infer that introduction of Au during contamination
with host kimberlite is unlikely to account for the observed
positive anomalies. One could alternatively suggest that Au is
stabilized in refractory alloys during mantle melting, based on
the observation that Au does not enter into mantle sulfides.
However, the Au enrichment in magmatic sulfide ores clearly
indicates that Au behaves incompatible during mantle melting,
consistent with the high D values of Au with regard to
sulphide liquid (D ~ 1000, Barnes and Lightfoot, 2005). The
formation of distinct Au-rich phases associated with sulfides
can be explained by the fact that the ionic radius of Au is too
large to fit into the structure of mss or iss. As the solubility of
Au in basaltic magmas is >10 ppm, Au will be released to the
magma during partial melting of the mantle. In conclusion, our
preferred model is that the relative Au enrichment in the
cratonic SCLM formed through metasomatic introduction of
Au, implying mobility of Au in the mantle. This is consistent
with derivation of at least some orogenic gold from the
SCLM.
Mineralogical Magazine
1389
Local structure of poorly ordered
nanosized iron oxides. Implications
for contaminants scavenging
F. MAILLOT1, G. MORIN1, C. CASIOT2, Y. WANG1,
D. BONNIN3, C. CHANEAC4 AND G. CALAS1
IMPMC, CNRS – UPMC, Paris, France
Hydrosciences, CNRS-Universités Montpellier I and II-IRD,
Montpellier, France
3
Laboratoire de Physique et d’Etude des Matériaux, ESPCI
ParisTech, Paris, France
4
CMCP, CNRS – UPMC, Paris, France
1
2
Iron (oxyhydr)oxides nanoparticles are ubiquitous in
natural environments (soils, rivers, sediments…), as well as in
impacted systems such as acid mine drainage, where they
strongly impact the mobility of most trace elements. Among
these (oxyhydr)oxides, the poorly crystalline minerals
ferrihydrite and schwertmannite are the most efficient in the
scavenging of toxic solutes such as arsenic, either via sorption
or coprecipitation mechanisms. The knowledge of the
structure of these compounds is a prerequisite to the
understanding of their surface reactivity. However, due to
their nanoparticulate nature and to the lack of well-crystallized
isomorph compounds, their structure remains poorly
constrained. Recent X-ray scattering studies [1, 2] have yield
unique information on the medium-range order in these
materials. However, for such disordered nanomaterials,
scattering techniques that yield average periodic structural
models may fail at accurately describing the local coordination
sphere of cations. To overcome this difficulty, we have used
Extended X-ray absorption fine structure (EXAFS)
spectroscopy to determine the local coordination and
arrangement of cations in these poorly ordered solids. Using
EXAFS data recorded at liquid helium temperature over a
wide energy range, we will particularly discuss the presence of
tetrahedral iron in ferrihydrite [3], and the structural
specificities of natural and synthetic schwertmannites
coprecipitated in the presence of arsenic. The structural
information derived from these data will be compared with
existing structural models, and yield clues for better
understanding the reactivity of these materials.
[1] F.M. Michel et al. (2007) Science 316, 1726–172.
[2] A. Fernandez-Martinez et al. (2010) Am. Mineral. 95,
1312–1322. [3] F. Maillot et al. (2011) Geochim. Cosmochim.
Acta 75 2708- 2720!
www.minersoc.org
Goldschmidt Conference Abstracts
1390
Inverse estimates of the air-sea flux of
carbon using surface pCO2
measurements
Using discrimination analysis for
anomaly separation and distinguish
the mineralized factors
JOSEPH MAJKUT AND JORGE L. SARMIENTO
Princeton University, Princeton, NJ, USA 08544
(*correspondence: [email protected])
A new method of estimating the historical pCO2 at the seasurface is used to estimate the air-sea CO2 flux and the time
rate of change of #pCO2 from 1980 through 2010. Using a
large surface pCO2 measurement database [1], which despite
its size sparsely represents much of the ocean over the past 40
years, we find optimal estimates of the pCO2 using
information from global circulation models and a simplified
model of pCO2 in the surface water. The simplified model
describes the time evolution of surface pCO2 on a 5x4 ° grid
according to
The third term, pCO2' (t), represents the interannuallyvarying seasonal cycle and other interannual variations in
pCO2 diagnosed from a series of simulations using the GFDL
MOM4.1 ocean general circulation model and the BLING
biogeochemistry model (OGCM). For each grid box, we
estimate the model parameters A, B and C by evaluating
likelihood against the data using a bayesian markov chain
monte carlo technique (MCMC) [2].
The resulting pCO2 trends and diagnosed fluxes are
provocative. The method indicates an ocean sink for
anthropogenic carbon of 2.7 +.15 Pg C for the year 2000. The
estimated annual rate of change of the #pCO2, used as an
indicator of flux trends, shows where the ocean is changing at
a rate significantly different than the atmosphere. The implied
air-sea carbon flux is increasing over much of the ocean, with
exceptions in the Northern Atlantic and Pacific basins.
Projections and hindcasts of the ocean carbon sink that are
based on OGCM simulations rely on the response of the
OGCM to climate change. The framework proposed here
allows us to evaluate that modeled response, of the carbon
cycle to climate change, against the observations. We present
regional analysis indicating whether or not modeled trends and
feedbacks are occuring in the real earth system.
[1] Takahashi et al. (2010) ORNL/CDIAC-152, NDP 088
[2] Hastings, W. K. (1970) Biometrika 57(1), 97–109.
Mineralogical Magazine
M.J. MAJLESI1*, M. MEMARZADEH1,
R. GHAVAMI- RIABI1 AND H. ASADI-HARONI2
Mining, Petrolum and Geophysics Faculty, Shahrood Univ. of
Tech, 7 Tir square, Danshgh Bolv
(*correspondence: [email protected])
2
Mining Engineering Dept., Isfahan Univ. of Tech., Khomani
shahr Bolv
1
Distinguish the mineralized factors in anomaly data
In the current research, the abilities of the discriminant
analysis in distinguishing anomaly from background [1, 2, 3]
for soil lithogeochemical samples in porphyry Cu-Au- Dalli
area (Iran) was shown. A group of 163 samples with sample
space of 50*50 m2 were used. According to the results (Fig. 1),
three populations were separated in data set (Fig. 1a). The
second group (code 2) is related to the anomalous subpopulation, the first group (code 1) is considered as mixture of
background and anomalous sub-population and the zero group
(code 0) is shown the background sub-population. In the
anomalous sub-population, the elements of Au and Cu (Fig.
1b) are introduced as mineralized factors, the elements of V,
Fe, P, Y, Ba, and Sc are important in the mixed subpopulation.
a
b
Figure 1: Discrimination analysis, anomly separation (a) and
mineralized factor (b).
Conclusion
One of the charactristic of the discrimination analysis as
anomaly separation method in compare with the other
methods is the identification of the mineralized factors or
elements.
!
[1] Davis, J.C. (2002) John Wiley & Sons, 646 pp. [2] Peh, Z.
& Halami(, J (2010) J. Geo. Expl. 107, 30–38.
[3] www.statsoft.com/textbook/stathome.html.
www.minersoc.org
Goldschmidt Conference Abstracts
Thermodynamics of crystalline
iron(III) arsenates scorodite, ka!kite,
and bukovsk"ite
Sr and Nd isotope disequilibrium in
migmatites and leucogranites, the
Higo metamorphic terrane, Japan
J. MAJZLAN1, P. DRAHOTA2, M. FILIPPI3, M. NOVÁK4,
J. LOUN4 AND K.-D. GREVEL1
Institute of Geosciences, Friedrich-Schiller University, Jena,
Germany (*correspondence: [email protected])
2
Institute of Geochemistry, Mineralogy and Mineral
Resources, Charles University, Prague, Czech Republic
3
Institute of Geology AS CR, Prague, Czech Republic
4
Department of Geological Sciences, Masaryk University,
Brno, Czech Republic
1
The crystalline ferric arsenates are candidates for arsenic
storage at sites contaminated by this metalloid. The
remediation technologies today usually involve precipitation
of poorly crystalline hydrous ferric oxide which is capable of
adsorbing As(V) or crystalline scorodite (FeAsO4·2H2O). We
seek alternatives which could be used for such processes, if
found to be advantageous. To this end, we study the
mineralogy and geochemistry of various sites polluted with
arsenic and measure the solubility of the arsenate minerals by
calorimetric techniques.
In this work, we present the formation enthalpies (#fHo) of
three arsenates, scorodite, ka)kite (FeAsO4·3.5H2O), and
bukovsk*ite (Fe2 (AsO4)(SO4)(OH)·9H2O). The #fHo values
were determined by acid-solution calorimetry at T = 298 K in
5 N HCl as the solvent, using HCl·9.96H2O, $-FeOOH, %MgSO4, MgO, KCl, and KH2AsO4 as the reference
compounds. The resulting values for scorodite, ka)kite, and
bukovsk*ite are –1508.9±2.9, –1940.2±2.8, and –4742.2±3.8
kJ/mol, respectively. We have also determined the #fHo value
for anhydrous FeAsO4 (not known as a mineral) as –899.0
±3.0 kJ/mol.
Scorodite served as a test of our approach as many studies
have been conducted on this phase (e.g. [1]). Using our #fHo
value and a Kopp rule estimate of entropy of 180.3 J/mol·K,
we arrive at a solubility product of –25.4, in good agreement
with –25.8 in [1] or –25.4 in [2]. Our data also predict ka)kite
to be unstable with respect to scorodite, in line with the rare
occurrence of ka)kite in nature.
The results presented here will be soon complemented by
heat capacity measurements and entropy calculations. Once
these data are secured, calculations of phase diagrams for the
title and related phases will be done and presented.
[1] Langmuir, D. Mahoney, J. Rowson, J. (2006) Geochim.
Cosmochim. Acta 70, 2942–2956. [2] Bluteau, M.-C.
Demopoulos, G.P. (2007) Hydrometallurgy 87, 163–177.
Mineralogical Magazine
1391
K. MAKI1,2*, J.G. SHELLNUTT2, T.W. WU3, Y. MORI4,
K. MIYAZAKI5, T.F. YUI2 AND B.M. JAHN2,6
Kyoto University, Kyoto 606-8502, Japan
(*correspondence: [email protected])
2
Academia Sinica, Taipei 11529, Taiwan
3
University of Western Ontario, Ontario N6A 5B7, Canada
4
Kitakyushu Museum of Natural History and Human History,
Kitakyushu 805-0071, Japan
5
Geological Survey of Japan, AIST, Tsukuba 305-8567, Japan
6
National Taiwan University, Taipei 106, Taiwan
1
Sr and Nd isotope compositions of migmatites and
leucogranites in the highest grade zone of the Higo low-P
/high-T (andalusite-sillimanite type) metamorphic terrane,
central Kyushu, Japan, suggest that the nebulitic migmatites
(diatexite) formed due to melt infiltration into the pelitic
gneisses, and the stromatic migmatites (metatexite) due to in
situ partial melting of the pelitic gneisses. The nebulitic
migmatites occur as a 3 m-thick layer and is sandwiched
between 2 m-thick layers of storomatic migmatites within
pelitic gneisses. Both types of migmatites are parallel to the
foliation of the gneisses. The leucogranites occur as a few to
ten cm-thick layer or lens within the gneisses. The nebulitic
migmatites preserve a record of large magnitude Sr and Nd
isotope disequilibrium with the pelitic gneisses, which show
the isotope equilibrium with the stromatic migmatites. The
nebulitic migmatites have higher epsilon Nd (T) values of -0.6
and P2O5 contents of 0.42 wt.% than those of the pelitic
gneisses (-2.1 and 0.18 wt.%) and stromatic migmatites (-3.1
and 0.10 wt.%). The initial 87Sr/86Sr ratio, ISr, of the nubulitic
migmatite, 0.70572, is lower than that of the pelitic gneisses
and stromatic migmatites ranging from 0.70792 to 0.70857.
Some leucogranites with high P2O5 contens of 0.91 wt.% have
the higher epsilon Nd (T) values of +3.4 than, and similar ISr
value of 0.70800 to that of the pelitic gneiss and stromatic
migmatites. Based on the Sr and Nd isotope characteristics
and P2O5 contents, in situ partial melting of the pelitic gneisses
could form the stromatic migmatites, but could not produce
the nebulitic migmatites with the higher epsilon Nd (T) value
and P2O5 contents. The higher epsilon Nd (T) value and P2O5
contents may imply the participation of externally derived
melt during the formation of nebulitic migmatites. Dissolution
of apatite into the melt under dry and high-temperature
conditions might produce such a high degree of Nd isotope
disequilibrium and high P2O5 contents.
www.minersoc.org
1392
Goldschmidt Conference Abstracts
Adsorption of organophosphorous
compounds on well-characterized
iron mineral nanoparticles
Microbiological investigation of the
Iron-containing floculent mats in
various deep sea environments
PETER MÄKIE1, PER PERSSON1 AND LARS ÖSTERLUND2,3
Dep. of Chemistry, Umeå Univ., SE-901 87 Umeå, Sweden
([email protected], [email protected])
2
FOI CBRN Defence and Security, SE-901 82 Umeå, Sweden
([email protected])
3
Dep. of Engineering Sciences, The Ångström Laboratory,
Uppsala Univ. SE-751 21 Uppsala, Sweden
([email protected])
H. MAKITA1*, S. KIKUCHI2, S. MITSUNOBU3,
K. NAKAMURA1, T. TOKI4, S. KAWAGUCCI1,
T. NOGUCHI5, M. ABE1, J. MIYAZAKI1, T. YAMANAKA6,
S. TSUCHIDA1, H. NOMAKI1, Y. TAKAHASHI2
1
AND K. TAKAI
1
Particles of iron (hydr)oxides in the eartht’s crust are
highly reactive towards phosphates, and sorption of
organophosphorous (OP) compounds constitutes an important
part of the anthropogenic phosphor cycle [1]. In this study,
three different polymorphs of well-characterized nanoparticles
were chosen as model systems for iron minerals, i.e. hematite
(+-Fe2O3), maghemite (,-Fe2O3) and and goethite (+-FeOOH).
Comparative studies of structure-specific sorption processes
were performed using three OP compounds, namely trimethyl
phosphate (TMP), triethyl phosphate (TEP) and dimethylmethyl phosphonate (DMMP). Using in situ infrared
vibrational spectroscopy, calibrated OP adsorption
measurements were performed in a temperature controlled
system under different conditions: Dry sorption with and
without irradiation by simulated sunlight, and sorption under
controlled humidity with and without sunlight.
The surface reactivity was shown to be strongly dependent
on detailed bonding coordination of the central P atom, the
structre of iron mineral surface, and environmental parameters
(humidity and sunlight). All OPs were found to adsorb
through the phosphoryl O atom on unsaturated iron cation
surface sites (Lewis acids) on hematite and maghemite. In
contrast, on goethite hydrogen bonding to surface OH
(Brønstedt acid sites) dominates. On the iron oxides
dissociative adsorption is facile yielding predominantly
methoxy and formate reaction intermediates (oxidative
pathway), and predominantly methoxy and phosphoric acid on
the hydroxide (hydrolysis). The reactivity increases in the
order goethite < maghemite < hematite. Addition of water
blocks reactive adsorption sites, whereas sunlight strongly
promotes OP dissociation on all minerals. Absence of water
favours oxidation on hematite and maghemite, whereas
presence of water during sunlight irradiation yields a
combined oxidation/hydrolysis pathway.
[1] Schnurer, Y. et al. (2006) Env. Sci. & Technol. 40, 4145–
4150.
Mineralogical Magazine
Japan Agency for Marine-Earth Science and Technology
(JAMSTEC), Kanagawa 237-0061, Japan
(*corrspondence: [email protected])
2
Hiroshima University, Hiroshima 739-8526, Japan
3
University of Shizuoka, Shizuoka 422-8526, Japan
4
University of the Ryukyus, Okinawa 903-0213, Japan
5
Kochi University, Kochi, 783-8502, Japan
6
Okayama University, Okayama, 700-8530, Japan
1
It is believed that most important energy source in ocean
crust or subseafloor is vastly abundant iron. Therefore, it is
suggested that the iron-oxidizing chemolithoautotrophic
microbe is a key player for the microbial ecosystem. However,
there were no direct evidences because cultivation of iron
oxidizer was difficult.
Recently, ‘Mariprofundus ferrooxidans’ belong to the (zeta)-proteobacteria [1] was isolated. This microbe can
oxidize ferrous iron as the elctron donor and can be widely
observed in various deep-sea low-temperature hydrothermal
fields [2].
However, the diversity, distribution and role of these ironoxidizing --proteobacteria are still unknown. In addition, it is
still unclear how these microbes cope with iron predominantly
from oceanic basalts.
Therefore, to clarify these questions, we have investigated
several iron-containing flocculent mats from deep-sea
hydrothermal fields in the Mariana Vocanic Arc and the
Okinawa Trough. Culture independent analysis of these mats
demostrated that --proteobacteria was the most dominant
phylotypes. The X-ray analysis (XANES and EXAFS)
revealed that the abundance of potentially biogenic Fe-oxidesspecies would be relevant with the abundance of -proteobacteria population in the iron-containing flocculent
mats. These results strongly supported that iron-oxidizing
chemolithoautotrophs have significant ecological roles for iron
and carbon cycles in deep-sea low-temperature hydrothermal
systems.
[1] Emerson D. et al. (2007) PLoS ONE 2, e667. [2] Emerson
D. & C. L. Moyer (2010) Oceanography 23, 148-163.
www.minersoc.org
Goldschmidt Conference Abstracts
Recycled crust in the source of
Deccan flood basalts
Serpentinite channel and the role of
serpentinite buoyancy for
exhumation of HP rocks (Voltri
Massif, Western Alps)
K. MALAMOUD1*, A.V. SOBOLEV1,2, D.V.KUZMIN2,
S. VILADKAR3 AND A.W. HOFMANN2
ISTerre, University J. Fourier BP 53, 38041 Grenoble Cedex
9, France
(*correspondence: [email protected])
2
Max Planck Institute for Chemistry, Postfach 3060, 55020
Mainz, Germany
3
Carbonatite Research Centre, Amba Dongar, Kadipani,
District Vadodara 390117, India
1
The Deccan Flood Basalts (DFB), Seychelles plateau and
Mascarene Islands (e.g. Réunion) are thought to trace the
evolution of a single mantle plume from its initial stage under
thick continental lithosphere to a hot-spot stage under thinner
oceanic lithosphere. DFB may also have contributed to the
Cretaceous-Tertiary-boundary mass extinction [1].
We intend to reconstruct the source compositions of lavas
from the DFB and the Mascarene Islands using the
compositions of melt inclusions and host olivine phenocrysts
following [2]. Preliminary results on samples from the Kutch
district (Gujarat state, India) indicate significant Ni excess and
Mn deficiency in the composition of olivine phenocrysts
similar to Hawaiian magmas (see Fig). This suggests a large
contribution of pyroxenite-derived melt (recycled oceanic
crust). Furthermore, this component appears compatible with
that of lavas from the Réunion Island.
Figure 1: Proportion of pyroxenite derived melt from Ni
excess and Mn deficiency in averaged (per sample) olivine
compositions [2].
C. MALATESTA1, T. GERYA2, M. SCAMBELLURI1,
L. FEDERICO1, L. CRISPINI1, G. CAPPONI1
Dipartimento per lo studio del territorio e delle sue Risorse,
Università di Genova, Corso Europa 26, Genova - Italy
2
Institute of Geophysics, ETH Zentrum, Sonneggstrasse 5,
8092 Zürich (Switzerland)
1
The high-pressure (HP) Voltri Massif (at the eastern end
of the Western Alps) consists of meta-ophiolites and
metasediments recording peak blueschist (Palmaro-Caffarella
Unit) to eclogite (Voltri Unit) facies. Eclogite and blueschist
metagabbro lenses within highly sheared serpentinite or
metasediments reveal strain heterogeneity within the lenses
and between lenses and host-rocks. P-T pseudosections of
these rocks indicate clockwise P-T paths for subduction and
exhumation. Peak conditions range from 10-15 kbar and 450500°C (Palmaro-Caffarella), to 21 kbar and 450-490°C, and to
22-28 kbar, 460-500°C (Voltri). To constrain exhumation of
these rocks, we performed 2D numerical models simulating
intraoceanic subduction in a basin surrounded by continental
margins, same as the Mesozoic Ligurian Tethys. We
reproduced a non-layered lithosphere typical of slow and
ultra-slow spreading ridges, where serpentinized lithospheric
mantle hosts discrete gabbro intrusions and is discontinuously
covered by basalts. As the result of slab dehydration, a viscous
serpentinite channel forms in the mantle wedge, whose
evolution is strongly controlled by rheology of serpentine.
Ductile deformation of serpentine within the channel enhances
mixing of parts of the overriding plate with slab-derived
sediments, oceanic crust and mantle. The simulations show
that serpentinites decreased the bulk density of HP terrains
below the mantle value, causing exhumation of part of the
serpentinite channel. They also provide P-T paths of selected
rock volumes with close correspondence with the P-T paths of
the Voltri gabbroic lenses. The dominance of highly sheared
serpentinite, the strong strain-partitioning, the metamorphic
peaks attained by the various rock volumes within the Massif,
and the similarity of natural and simulated P-T paths, suggest
that the Voltri Massif may represent a ‘fossil’ serpentinite
channel.
[1] Courtillot, V. et al. (1988) Nature 333, 843–846.
[2] Sobolev, A.V. et al. (2008) Science 321, 536.
Mineralogical Magazine
1393
www.minersoc.org
Goldschmidt Conference Abstracts
1394
Sr and Nd isotope studies on
sediment core samples from Cauvery
delta, South India: Evidence for
monsoon induced changes in
provenance
MALIK ZUBAIR AHMAD, S. BALAKRISHNAN AND
P. SINGH*
Department of Earth Sciences, Pondicherry University,
Pondicherry 605014, India
(*correspondence: [email protected])
Sr and Nd isotope composition of sediments are useful to
trace their provenance and past changes in climate [1]. Here,
we present 87Sr/86Sr ratios of four different leachate fractions
and Sr and Nd isotopic composition of the residual detrital
phase of the sediments from a 25 m core obtained from the
distal part of the Cauvery River delta. The 87Sr/86Sr ratios of
exchangeable, carbonate, Fe-Mn and organic phases of the
sediments exhibit similar trends falling between seawater and
river water values (Fig.1). All these phases exhibit a sharp
positive excursion at 3.8 m depth. This could be due to
stabilization of vadoze zone for a long period, permitting
greater microbial assisted weathering of minerals to release
more radiogenic Sr.
Figure 1.
Redox conditions of formation of
osmium-rich alloys from dunite and
chromitite of the Guli massif
(Maimecha-Kotui Province, Russia)
K.N. MALITCH1*, A.A. KADIK2, BADANINA I.YU.1
2
AND E.V. ZHARKOVA
Russian Geological Research Institute, St. Petersburg,
199106, Russia (*correspondence: [email protected])
2
Institute of Geochemistry and Analytical Chemistry, Russian
Academy of Sciences, Moscow, 119991, Russia
([email protected])
1
This study presents the new data on mineral composition
and physico-chemical conditions of formation of Os-rich alloy
grains derived from dunite and chromitite of the Guli
clinopyroxenite-dunite massif (Maimecha-Kotui Province,
Russia). The study employed a multitechnique approach that
utilized electron microprobe analysis and experimental
determination of the intrinsic oxygen fugacity (fO2) of Os-rich
alloys using solid electromechanical cells.
Measured fO2 values of native osmium (Os84Ir11Ru5) and
iridian osmium (Os66Ir28Ru5) are plotted (Fig. 1) between
standard equilibrium buffers of wustite – magnetite (WM) and
quartz – fayalite – iron (QFI). The similarity of fO2 for Osrich alloys from dunite and chromitite indicates that formation
of these minerals occurred in compatible redox conditions,
characteristic of the region of generation of mantle peridotites.
Figure 2.
Comparison of trends of !Ndo and 87Sr/86Sr ratios in the
detrital phase of the sediments shows five excursions (Fig. 2).
Comparing the isotope ratios of rocks exposed from the
catchment of Cauvery river suggest that the dominant source
of sediments varied from (1) granitic gneisses and basalts of
Dharwar craton exposed along northern westcoast, receiving
rains during southwest monsoon (2) enderbites and granulites
of Nilgiri mountains that receive rainfall during both
southwest and northeast monsoon and (3) gneisses and
granulites found along Moyar, Bhavani and Cauvery shear
zones and Southern Granulite Terrain receiving rains during
NE monsoon. Evidence for intensification of SW monsoon is
observed at a depth of 4 m upward (~7800 years B.P.) to
1.85m (upto ~5990 years B.P.).
Figure 1: Plot log fO2 - 104/T (.) for the measured samples of
native osmium from dunite and iridium osmium from
chromitite.
The study was supported by Russian Foundation for Basic
Research (grant / 09-05-01242).
[1] Goodbred (2003) Sedimentary Geology 162, 83–104.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Late metasomatic addition of garnet
to the SCLM: Os-isotope evidence
V.G. MALKOVETS1*, W.L. GRIFFIN2, N.J. PEARSON2,
D.I. REZVUKHIN1, S.Y. O’REILLY2, N.P. POKHILENKO1,
V.K. GARANIN3, Z.V. SPETSIUS4 AND K.D. LITASOV1
V.S. Sobolev Institute of Geology and Mineralogy,
Novosibirsk, 630090, Russia
(*correspondence: [email protected])
2
GEMOC National Key Centre, Macquarie University,
Sydney, 2109, Australia ([email protected])
3
Moscow State University, Moscow, Russia
4
ALROSA Ltd., Mirny, Russia
1
Archean cratons are underlain by highly depleted
subcontinental lithospheric mantle (SCLM). However,
xenolith and xenocryst data [1; references therein] suggest that
Archean SCLM has been extensively refertilized by
metasomatic processes, with the addition of Fe, Ca, and Al to
depleted protoliths. The distribution of sub-calcic garnets in
the SCLM beneath the Siberian craton suggests (1) sub-calcic
garnets and diamonds are metasomatic phases in the cratonic
SCLM; (2) the distribution of both phases is laterally
heterogeneous on relatively small scales and related to ancient
structural controls [2].
Re-Os isotopic compositions of sulfide inclusions in
lherzolitic Cr-pyropes from four Siberian middle Paleozoic
diamond mines have been determined by laser ablation MCICP-MS: Mir (n=17) and Internationalnaya (n=109),
Malobotuobiya field, Udachnaya (n=17), Daldyn field, and
Nyurbinskaya (n=12), Nakyn field.
Most analysed sulfides (~84%) have very low Re/Os ratios
(<0.07), and their Re-depletion ages (TRD) fall between 2.2 and
3.0 Ga (±0.03 Ga, mean 2s analytical uncertainty). 10 to 15%
of the sulfides give younger TRD down to 600 Ma.
Our previous study [3] of sulfide inclusions in megacrystic
olivines from the Udachnaya pipe suggests that most of the
SCLM beneath the Daldyn kimberlite field formed at 3-3.5
Ga, and that lithosphere formation culminated at ca 2.9 Ga.
Our new data suggest that refertilization of the highly depleted
SCLM and the introduction of Cr-pyrope garnet occurred
between 2.2 and 3.0 Ga; little garnet was present before 3 Ga.
Pyropes with young sulfides (between ~1.9 and ~2.2 Ga) may
have crystallised during the amalgamation of the Siberian
craton in Paleoproterozoic time.
[1] Griffin et al. (2009) Jour. of Petrol. 50, 1185–1204.
[2] Malkovets et al. (2007) Geology 35, 339–342. [3] Griffin
et al. (2002) Geochem. Geophys. Geosyst. 3, 1069.
Mineralogical Magazine
1395
On dating of groundwater with a
high 234U/238U and Eh> 100mV
A.I. MALOV
Institute of the Ecologic Problems of the Northern Region,
Naberezhnaya Severnoi Dviny, Arkhangelsk, 163061,
Russia ([email protected])
In this report, on the basis of geological dating and
developed PI Chalov method for determining the age of
surface water for non-equilibrium uranium, attempted to
assess the possibility of using isotopes U to determine the age
of groundwater. In alpha-decay of 238U atoms in an unbroken
part of the mineral species appears disorders (disordered)
region (d. r.) formed by atom recoil 234Th. Among disordered
may be the atom itself and the impact that formed this region.
The probability of this event, p: 0 <p <1. If the groundwater is
constantly supplied nonequilibrium uranium 234U/238U>1 (!d. r.)
within a certain time t, then the following expression:
" d .r. = (" t.water #1)
$2 t
+1.
1 # ?# $2t
Therefore, asking a few randomly chosen values of t, we
can define the corresponding values !d. r.. Then get some
corresponding values N1rocks / p:
N1rocks
"2
=
.,
?
"1 (# dr $ # rocks )
where N1rocks - the number of atoms of 238U, "1 = 1.55 • 10years-1 and "2 = 2.75 • 10-6 years-1 - decay constant of 238U
and 234U. Knowing the number of atoms of 238U, located in the
water contained in a unit volume of rock Vunit is currently
N1unit.. water, and the activity of 238U of the mineral species in the
same volume #1unit. rocks, you can roughly estimate the average
number of atoms N1rocks goes into the water from a disordered
region:
10
N1rocks "
N1unit.water
.
?1unit.rocks # t
Having obtained the values N1rocks/p and N1rocks, we define
p. As a result, for each of several arbitrarily chosen values of t
we obtain the corresponding value of probability p. The values
of t and p are related by a power dependence. Therefore,
defining p, for several values of t, we can derive an equation
of type t = ap-0.971, where a - the age of groundwater at $=1%,
and construct the corresponding diagram. The key point of the
proposed method is the choice for charting the calculated
value of p, on which is t, age-appropriate groundwater. On the
example of North Dvina basin (northwest Russia) have shown
that for aquifers with a high 234U/238U and Eh> 100 mV in
increments homogeneous sandy rocks, p value is 0.35%. It is
important to note that the chemical dissolution of equilibrium
uranium contained in areas of undisturbed radioactive decay
of rocks, as well as sorption to the results of calculations by
the proposed method is not influenced.
www.minersoc.org
1396
Goldschmidt Conference Abstracts
Progress in understanding of sulfur
in subduction zone magmas
C. MANDEVILLE1*, N. SHIMIZU2, K. KELLEY3,
N. METRICH4, A. FIEGE5 AND H. BEHRENS5
US Geological Survey ([email protected])
2
Woods Hole Oceanographic Institution ([email protected])
3
University of Rhode Island ([email protected])
4
Institut de Physique du Globe de Paris ([email protected])
5
Univ. of Hannover ([email protected])
1
Progress in developing a better understanding of sulfur’s
behavior and origin in subduction zone magmas has now been
facilitated through new in situ analytical techniques and recent
conduction of high pressure and temperature (P-T) partitioning
and isotopic fractionation experiments. Development of an in
situ secondary ionization mass spectrometry (SIMS) technique
for measurement of 34S/32S ratios in silicate glasses now allows
for direct measurements of experimental glasses and melt
inclusions from mafic arc magmas. Complementary SIMS
calibrations for sulfur isotope ratio measurements of pyrrhotite
and anhydrite now allow for investigation of S isotopic
fractionation between sulfur-bearing melt and condensed
sulfur phases at magmatic temperatures. Conventional and
SIMS analysis of run products from high (P-T) decompression
experiments investigating S partitioning between vapor and
melt (Fiege et al. [1]) provide direct measurement of isotopic
fractionations that can now be compared to estimates derived
from previous extrapolations of data from lower temperature
experiments, analogue materials and/or theoretical models [2].
Advances in S and Fe micro-X-ray Absorption Near Edge
Structure Spectroscopy (XANES) has allowed for
determination of the oxidation state of S and Fe in both natural
and experimental samples.
Measured 34S/32S ratios via SIMS in olivine-hosted
basaltic melt inclusions (MI’s) from Krakatau and
Galunggung volcanoes in Indonesia and Augustine volcano,
Alaska yield "34S values from -2.8‰ to 17.2‰. Highest "34S
values of 9.6‰ to 17.2‰ were measured in MI’s from a
Pleistocene basalt from Augustine volcano that have high
disolved volatiles of 8.0 wt.% H2O, 2624 to 5100 ppm S, 3900
ppm Cl, and sulfur XANES spectra with prominent peaks at
2482 eV indicating 100% SO42- species in melt. Melt
inclusions from the 1982 eruption of Galunggung yield "34S of
-2.8‰ to 9.6‰. Melt inclusions from Krakatau pre-1883
basaltic scoria yield "34S values of 1.6‰ to 8.7‰. A34Senriched material is present in these magma source regions.
Mn-crusts record deep ocean
ventilation changes
AUGUSTO MANGINI
Heidelberger Akademie der Wissenschaften, INF 229,
D-69120 Heidelberg ([email protected])
The end of glacial stages is accompanied by an increase of
atmospheric CO2. During the last Termination this increase
goes along with a drastic drop of atmospheric 14C by about
190‰. The probable explanation assumes the release of old
carbon stored from a poorly ventilated glacial Ocean. This
period was addressed by Broecker as the ‘Mystery Interval’
due to lacking higher glacial Benthic-Planktic foraminifera
ages. However, the mystery could be an artefact of the tool
applied, as benthic foraminifera cannot survive in an anoxic
ocean.
More than 20 years ago we had measured profiles of 230Th
in the top mm of two Mn-crusts from the Central Pacific, from
4, 400 m and 1, 500 m water depth at a resolution of 20µm. In
both samples growth rates during the past 300, 000 years were
faster in Interglacials than in Glacials. We attributed the
extremely slow growth rate during stage 2, and, especially,
stops of growth during glacial stages 6 and 8 to periods of
anoxia of the deep ocean, impeding formation of Mn-oxides.
However, these conclusions were ignored, arguing that the
occurrence of benthic forams and the lack of peaks of uranium
in sediments contradicted periods of anoxia. In the meantime,
however, there are a number of indications that the deep
glacial Pacific Ocean was less ventilated than at present and
that the shut down of N. Atlantic deep water formation during
Heinrich 1 could have led to a short anoxic period in the deep
Pacific. Reconsidering the data from the Mn crusts may help
to solve the mystery.
[1] Fiege et al. (2011) MinMag, this volume. [2] Mandeville et
al. (2009) GCA 73, 2978–3012.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Geochemical implications of iodine
distribution in Indian soils
DEVLEENA MANI*, D.J. PATIL AND A.M. DAYAL
Petroleum Geochemistry Group, National Geophysical
Research Institute(CSIR), Hyderabad-500007
(*correspondence: [email protected])
Iodine plays a pivotal role in many of the geological,
chemical and biological processes because of its litho-, bio-,
atmo-, hydro- and chalco-philic nature. Speciation of iodine as
inorganic iodine (iodides and iodates), molecular iodine and
organically bound iodine provides its chemical signature in
diverse forms in the earth crust. Contrasting distributions of
iodine are observed in the Indian soils; wherein iodine lows
below the permissible limits of WHO are observed in several
parts of India, especially in the northern region [1], and on the
other side, elevated iodine concentrations in hydrocarbon
prospective/petroliferous sedimentary basins of India have
been documented [2].
Soil iodine studies have been carried out in Saurashtra and
Deccan Syneclise basins, which are potentially prospective
hydrocarbon realms in the western and west central India,
respectively. Results show the concentration (in mg/kg) of
iodine to be in the range of 1.5-68.5 and 1.1-19.3 in the
surficial soils of Saurashtra and Deccan Syneclise,
respectively. The values are quite high compared to average
distribution of iodine in soils (0.01-6mg/kg) [3]. The iodine
highs in these regions appear to be associated with the
hydrocarbon prone organic matter of the sedimentary basins.
The geological and geophysical variations occurring in
different regions and sedimentary basins of India corroborate
the concentration distribution pattern of iodine in the soils and
the related geochemical anomalies.
[1] Ghose, et al. (2003) Journal of Geol. Soc. of India 62, 91–
98. [2] Mani et al. (2011) Natural Resources Research 20, 1,
75–88. [3] Kebata-Pendias & Pendias, (1984) Trace elements
in soils & plants, CRC Press.
Mineralogical Magazine
1397
HIMU-EMI type OIBs from the
Neoarchean Penakacherla greenstone
belt, Dharwar craton, India:
Implications on Recycling of
Mesoarchean crust
C. MANIKYAMBA1 AND R. KERRICH2
National Geophysical Research Institute (CSIR), Hyderabad606, India; ([email protected])
2
Univeristy of Saskatchewan, Skatoon, Canada S7N 5E2,
([email protected])
1
Alkaline basalts, having relict aegirine, leucite and
nepheline mineralogy, are associated with high-Mg and island
arc basalts in the Neoarchean Penakacherla greenstone belt,
eastern Dharwar craton, India. These are compositionally
uniform, where SiO2 = 43 to 46 wt%, Mg# = 0.70 to 0.58, and
Ni = 183-85 ppm, enriched in alkalies (K2O+Na2O ~7 wt.%),
TiO2 (2.3-2.1 wt.%), and exhibit fractionated REE patterns
with (La/Yb)N ranging from 23 to 29. On the Ni-Zr diagram,
alkaline basalts plot with counterparts from the ocean island of
Tubuai, Cook-Austral volcanic chain. On paired REE and
primitive mantle normalized multi-element diagrams these
basalts are characterized by coherent patterns: (1) smoothly
fractionated REE [(La/Sm)N 4.08-5.00, (Gd/Yb)N 3.09-4.27];
(2) uniform Th/U ratios (4.1-5.4); (3) no Ce or Eu anomalies;
(4) depletions of Th relative to Nb and La, yielding small
negative anomalies of Nb relative to La (Nb/La = 0.78-1.01
vs.1.04 the primitive mantle ratio, in common with
compositional characteristics of Phanerozoic alkaline ocean
island basalts (OIB). These basalts plot with Recent
counterparts from Aitutaki and Heard OIB on SiO2 vs Nb/Y
plot. High-µ, EM1 and EM2 OIB have distinct to overlapping
trace element characteristics, of which HIMU OIB alone are
characterized by positive Nb-anomalies. Comparison of PTalkaline basalts with average trace elements ratios of OIB end
members of Greenough et al. (2005) exhibit resemblance with
some features of HIMU and EM1. Ratios of Zr/Nb (2.7-3.61),
and La/Yb (32 - 41) compared to respective values in HIMU
(3.4, 30), EM1 (5.4, 36), and EM2 (6.3, 21). Ti/Y (559) and
Y/Yb (14) compare to respective values in HIMU (598, 13),
EM1 (680, 15) and EM2 (638, 16). Consequently, PT alkaline
basalts have trace element ratios intermediate between HIMU
and EM endmembers. This occurrence of alkaline basalts
indicates subduction, recycling, and incubation of
Mesoarchaean oceanic and continental crust in the mantle, and
generation of a mantle plume at 2.7 Ga.
www.minersoc.org
1398
Goldschmidt Conference Abstracts
Nutrient uptake at the fungi-mineral
interface
UTRA MANKASINGH1*, SALVATORE A. GAZZE2,
LOREDANA SACCONE2, ADELE L. DURAN3,
JONATHAN R. LEAKE3
1
AND KRISTIN VALA RAGNARSDOTTIR
Faculty of Earth Sciences, School of Engineering and Natural
Sciences, University of Iceland, Askja, Sturlugata 7,
Reykjavik 107, Iceland (*correspondence: [email protected])
2
H.H. Wills Physics Laboratory, University of Bristol, Tyndall
Avenue., Bristol, BS8 1TL, UK
3
Department of Animal and Plant Sciences, University of
Sheffield, Western Bank, Sheffield, S10 2TN, UK
1
This study focuses on the central role of soil fungi to
acquire mineral nutrients from rocks and minerals, and thus
participate in the weathering of bedrock to soil. We investigate
fungal uptake of nutrient elements from minerals via direct
contact and transport across the organism membrane.
Plant seedlings (Pinus sylvestris) in symbiosis with
ectomycorhyzal fungi were grown directly on mineral surfaces
in a controlled microcosm environment with regulated light,
nutrients, moisture and carbon dioxide. The seedlings were
grown in mixed mineral microcosms that were starved of a
single essential nutrient. Initial chemical analysis of foliage
and roots from microcosms starved of the major nutrients K
and Mg showed lower concentrations of these elements in
plant tissue compared to plants from microcosms that were not
starved of these elements. However, despite systems being
starved of K, an appreciably greater K concentration was
observed in the shoots vs roots, suggestive of K storage in the
foliage. Ca was also higher in shoots than roots. This trend is
perhaps indicative of water efflux in the plants. Similarly, the
essential nutrients P, Mg, Mn and Zn were higher in the
foliage than in the roots,
Conversely, Fe and Al concentrations are higher in the
roots than the shoots. Similar trends have been observed in the
literature, suggesting low mobility of Al and Fe in plants [1].
Al, which is a non-essential element to plants, is toxic to fungi
and they excrete it. The ready supply of Al to the roots system
and the selective uptake to the shoots could imply that fungi
may act as a filter for Al uptake by the seedlings. Fe uptake
needs to be further investigated through comparison of
systems with varying Fe nutrient supply.
[1] Hobbie et al. (2009) Comm Soil Sci Plan 40, 3503–3523.
Mineralogical Magazine
The role of North Atlantic
asthenosphere in the genesis of
Icelandic lavas: Evidence from
Heimaey
C.J. MANNING* AND M.F. THIRLWALL
Royal Holloway University of London, Egham Hill, Egham
Surrey TW20 0EX
(*correspondence: [email protected])
Recent work on Iceland has indicated minimal
involvement of North Atlantic asthenosphere (NAA) in the
genesis of Icelandic lavas [1, 2]. Whilst the variation in
isotopic and trace element compositions of Icelandic lavas
requires several distinct mantle sources, these are all suggested
to be derived from the Iceland plume rather than the
surrounding asthenosphere [2, 3, 4]. It follows that areas
remote from the current plume position are more likely to
exhibit evidence for interation with NAA. We present new
high-precision isotopic and elemental data for samples from
the island of Heimaey which is proposed to be the tip of the
propagating Eastern Rift Zone in South East Iceland.
In contrast to the incompatible element enrichment
expected in the small degree melts produced at off-rift zones,
the Heimaey samples exhibit lower concentrations (up to
21%) at a given MgO% than the South Iceland central
volcanoes. Despite this the Heimaey lavas still plot in the
alkali field on a TAS diagram which is a consequence of
enrichment in Na that is not coupled with enrichment in other
incompatible elements.
Relationships between K/Nb, Na2O/TiO2, and radiogenic
isotopes indicate mixing between an enriched component with
an ‘Icelandic’ signature and a depleted component similar to
NAA. Na2O/TiO2 has been shown to vary as a function of
melting depth [5] and polybaric melting models for Na2O/TiO2
indicate that the high values seen within the Heimaey samples
can be generated by mixing between <40% of an ‘Icelandic’
source melting in the garnet facies (~45kbar) and <72% of a
North Atlantic MORB source melting in the spinel facies
(~10kbar).
[1] Fitton et al. (1997) EPSL 153, 197–208. [2] Thirlwall et
al. (2004) GCA 68, 361–386. [3] Chauvel & Hemond (2000)
G3 1. [4] Kokfelt et al. (2006) J.Pet. 47, 1705–1749.
[5] Putirka (1999) JGR 104(B2) 2817–2829
www.minersoc.org
Goldschmidt Conference Abstracts
New roles for rutile in tracing
petrogenetic processes
C.E. MANNING
1399
Aqueous complexing and element
recycling by subduction-zone fluids
C.E. MANNING
Department of Earth and Space Sciences, University of
California Los Angeles, Los Angeles, CA 90095-1567
([email protected])
Department of Earth and Space Sciences, University of
California Los Angeles, Los Angeles, CA 90095-1567
([email protected])
Rutile is common in a wide range of igneous and
metamorphic systems. Its wide stability and mechanical
durability make it an important addition to the petrologist’s
accessory-phase toolkit. And, for at least two jobs, it may be a
better tool than its more commonly deployed partner, zircon.
First, rutile is nominally anhydrous but can contain up to 3000
ppm H2O, significantly more than zircon [1]. Thus, OH in
rutile can help evaluate the role of hydrous components during
petrogenesis. Colasanti et al. [2] determined OH solubility in
pure synthetic rutile at 0.5-2.0 GPa, 500-900 °C and four ƒO2
buffers using FTIR spectroscopy. OH solubility increases with
decreasing ƒO2 at fixed P-T, and with T or P at isobarically or
isothermally buffered ƒO2. Data support OH substitution via
Ti4+O2 + 1/2H2O = Ti3+O (OH) + 1/4O2, and yield nearly ideal,
multi-site mixing of the TiO2-TiOOH solid solution along with
!Vr°, !Hr° and !Sr° of 1.90±0.48 cm3/mol, 219.3±1.3 kJ/mol,
and 19.9±1.4 J/molK (1&). OH in rutile can be deployed as a
thermobarometer and/or oxybarometer. Elevated OH in rutile
may imply unexpectedly high Ti3+ in some terrestrial settings.
A second role for rutile arises from its participation in nettransfer reactions, which is rare for zircon [3]. This makes it
especially useful in thermobarometry [4]. Kapp et al. [5]
showed that solid solution in titanite leads to titanite-rutile
coexistence over a range of P and T, in turn permitting
titanite-rutile barometry. Evaluation of 2 zoisite/clinozoisite +
rutile + quartz = 3 anorthite + titanite + water (TZARS) and
anorthite + 2 titanite = grossular + 2 rutile + quartz (GRATiS)
reveals that using appropriate solution models both return P
within 0.5 kbar of independent constraints for a range of
lithologies and cotexts. Moreover, crustal rocks possess nearly
constant titanite activity, so accurate P is recorded even if only
one Ti-phase is present, greatly expanding the range of
assemblages on which TZARS and GRATiS can be deployed.
These two examples show that rutile may provide key insights
into conditions attending igneous and metamorphic processes.
Mineral solubility in pure H2O is a poor guide to assessing
minor-element transfer by subduction-zone fluids. This is
because all such fluids exist in a soluble rock matrix, and it is
the interactions with the major solutes derived from host
lithologies that exert the dominant controls on element
mobility. This can be seen with three examples. First, low
rutile solubility in pure H2O at subduction zone conditions [1]
fails to explain occurrence of this phase in veins in high P
rocks. However, TiO2 solubility is greatly enhanced dissolved
Na-Al silicates, via incorporation in Na-Ti complexes or NaAl-Si oligomers [1, 2]. Experimentally constrained solubility
data indicate that at 600 °C along model slab geotherms, rutile
solubility in H2O is 2 ppm Ti, whereas in H2O equilibrated
with cpx+mica+quartz the high dissolved Na-Al-Si [3] yield
88 ppm Ti. If albite-H2O fluids are supercritical, even greater
Ti transport is possible [4]. Alkali halides are also important
complexing agents. Tropper et al. [5] showed that at 800°C, 1
GPa, CePO4 monazite and YPO4 xenotime solubilities are very
low in pure H2O but are significantly enhanced by NaCl via
REE/Y-chloride and Na-phosphate complexing. This may
promote REE mobility; for example, H2O/Ce inferred for
subduction-zone melts and silicate-rich fluids [6] can also be
produced by a CePO4-saturated fluid with XNaCl = 0.1. Finally,
mineral-solute interactions fix pH in a given lithology and set
of conditions. The pH controls the solubility of amphoteric
metal oxides. It also governs volatile transfers, e.g. carbon.
Molecular CO2 from carbonate minerals is low along slab
geotherms. Most carbon is dissolved instead as carbonate. The
strong dependence of aragonite solubility on pH translates to
important controls by buffering mineral assemblages. Changes
in pH with P, T and bulk composition must be the primary
factors governing loss of carbon from slabs before they reach
sub-arc depths. In general, the strong influence of aqueous
complexing on element solubility highlights that the role of
fluids in element recycling can vary widely.
[1] Johnson (2006) Rev. Mineral. Geochem. 62, 117–154.
[2] Colasanti et al. (2011) Am. Min. in press. [3] Ferry et al.
(2002) Am. Mineral. 87, 1342–1350. [4] Manning & Bohlen
(1991) Contrib. Mineral. Petrol. 109, 1–9. [5] Kapp et al.
(2009) J. Metamorphic Geol. 27, 509–521.
[1] Antignano & Manning (2008) Chem. Geol. 255, 283–293.
[2] Manning et al. (2008) Earth Planet. Sci. Lett. 272, 730–
737. [3] Wohlers et al. (2011) Geochim. Cosmochim. Acta in
press. [4] Hayden & Manning (2011) Chem. Geol. 284, 74–81.
[5] Tropper et al. (2011) Chem. Geol. 282, 58–66. [6] Plank et
al. (2009) Nature Geosci. 2, 611–615.
Mineralogical Magazine
www.minersoc.org
1400
Goldschmidt Conference Abstracts
Chemical fractionation of Pb and Zn
and determination of Pb isotopes in
deposited blast-furnace sludge
TIM MANSFELDT, HENNING SCHIEDUNG
AND STEPHAN SCHUTH
Department of Geosciences, Soil Geography/Soil Science,
University of Köln, Germany
([email protected])
Blast-furnace sludge is a waste of pig iron production and
was deposited in large surface landfills. Since it contains high
amounts of Zn and Pb it is of environmental concern. The first
aim of this study was to investigate the solubility and binding
forms of Zn and Pb in this industrial waste.
We performed a five step sequential chemical
fractionation on 32 samples: (A) 1 M NH4NO3; (B) 1 M
NH4OAc, buffered at pH 5.4; (C) 0.2 M NH4-oxalate-buffer,
pH 3.25; (D) 0.1 M ascorbic acid + 0.2 M NH4-oxalate-buffer,
pH 3.25; (E) aqua regia.
The second aim was to determine the Pb isotope ratios of
representative bulk samples (n = 10) and related fractions (n =
3) with MC-ICP-MS.
Total contents of Zn ranged from 15, 720 to 86, 400 mg
kg-1 (median 30, 360 mg kg-1) and from 1, 420 to 19, 510 mg
kg-1 (median 9, 835 mg kg-1) for Pb. The proportion of the
mobile fraction (A) ranged from 0.09 to 2.11% (median
0.26%) for Zn and from 0 to 0.3% (median 0.04%) for Pb. For
the easily mobilized fraction (B) we obtained a range from 2
to 23% (median 7%) for Zn and from 5 to 68% (median 19%)
for Pb. In contrast to Zn, which is largely associated (63 to
96%, median 85%) to fraction C, i.e. poorly crystalline iron
oxides, Pb is much more distributed over the fractions D (4 to
26%, median 18%), i.e. crystalline iron oxides, and E (9 to
64%, median 39%). Sequential fractionation indicates that Zn
and Pb are bonded differently in blast-furnace sludge,
resulting in a contrasting mobility of these two elements.
The Pb isotope ratios of the bulk samples are clearly
distinguishable and ranged from 18.088 to 18.634
(206Pb/204Pb), 15.595 to 15.670 (Pb207/204Pb) and 37.709 to
38.402 (208Pb/204Pb). In contrast, the isotope ratios of the
different fractions show little variation, especially the 207Pb204
Pb ratios overlap within analytical uncertainty. No massdependent fractionation was observed between the different
fractions, because variation is higher for 207Pb/204Pb and
206
Pb/204Pb than for 208Pb/204Pb.
Mineralogical Magazine
Seasonal variation in the clay mineral
and Sr-Nd isotopic compositions of
the suspended sediments of the lower
Changjiang River at Nanjing, China
CHANGPING MAO1,2*, JUN CHEN1 AND JUNFENG JI1
Institute of Surficial Geochemistry, School of Earth Sciences
and Engineering, Nanjing University
2
State Key Laboratory of Pollution Control and Resource
Reuse, School of Environment, Nanjing University,
Nanjing 210093, China
(*correspondence: [email protected])
1
The clay minerals and Sr-Nd isotope signatures have been
extensively used to characterise the provenance of detrital
sediments and wheathering processes. The Changjiang (CR)
River is one of the largest rivers in the world. The CR
originates on the Tibetan Plateau and enters the East China
Sea. A large part of the CR Basin has a subtropical monsoon
climate. To examine seasonal changes in clay minerals and SrNd isotopic compositions of the CR, suspended sediment (SS)
samples were collected monthly for two hydrological cycles in
Nanjing city.
The results indicate that the concentration of CR SS
ranges from 11.3 to 152 mg/L and is highly correlated to the
rate of water discharge with a higher concentration in flood
season. Illite dominates the clay minerals of the CR SS,
followed by chlorite, kaolinite and smectite. Illite and
kaolinite show distinctly seasonal variations; SS has more
illite and less kaolinite contents during flood season than the
dry seasons. The illite chemistry index and crystallinity as
well as kaolinite/illite ratio all indicate intense physical
erosion in the upper CR basin during the flood season.
The Sr-Nd isotopic compositions (silicate fraction) also
show distinctly seasonal variations. The results indicate that
the 87Sr/86Sr ratios of CR SS ranges from 0.725352 to
0.738128, and the 0Nd (0) values ranges from 110.55 to
112.29. The relative decrease in 87Sr/86Sr ratios and increase in
0Nd (0) values during the flood season can be interpreted to
reflect an increasing in the mechanical erosion rate in the
upper basin and contribution of more radiogenic Nd and nonradiogenic Sr to the suspended load in flood season.
The Sr-Nd isotopic compositions correlate well with the
clay mineral associations, indicating that the seasonal
variations primarily reflect the controls of provenance rocks
and erosion between different sub-catchments. Furthermore,
these signatures can be now used to decipher past discharge
and flow regimes of the rivers from sediment cores offshore.
www.minersoc.org
Goldschmidt Conference Abstracts
Th inventories in new sediment
cores from the eastern equatorial
Pacific: Constraints on the 230Th
constant-flux proxy
230
FRANCO MARCANTONIO1, RAMI IBRAHIM1,
AJAY K. SINGH1 AND MITCHELL LYLE2
Department of Geology & Geophysics, Texas A&M
University, College Station, TX 77843, USA
(*correspondence: [email protected])
2
Department of Oceanography, Texas A&M University,
College Station, TX 77843, USA
1
We have conducted an oceanographic survey in the
eastern equatorial Pacific Ocean to assess the water and
sedimentary budget of 230Th along water flow paths into the
Panama Basin. Our survey, along ~85!W, included
bathymetric mapping, sub-bottom profiling, seismic reflection
data acquisition, and collection of water and new sediment
cores. Our goal is to address the controversy concerning the
use of 230Th activities as a constant-flux proxy in the Pacific
Ocean. Proponents of the 230Th technique maintain that
sediment redistribution is widespread in the eastern equatorial
Pacific and that the flux of laterally advected sediment can
surpass the vertically rained flux by up to 2-4 times. Others
suggest that there may be a discrepancy between the 230Th flux
and its rate of production which, in turn, causes accumulation
rates to be underestimated due to potential lateral transport of
230
Th in the water column. The crux of the disagreement
amounts to how one explains the larger-than-expected
inventories of sedimentary 230Th along the equator in the
Pacific, inventories above those expected from a constant
water column production rate.
The Carnegie gap region, bounding the southern border of
the Panama Basin, is the main deep water flow path into the
basin, and provides an ideal testing ground for investigating
sediment advection. Our seismic and sub-bottom profiling
surveys determined ‘end-member’ areas within this region
with both thick and thin sediment cover, and several of these
sites were multi- and piston-cored. The cores have been dated
via radiocarbon and XRF-major-element correlation, which
has enabled us to construct common stratigraphies in each
survey region. A high-resolution assessment of a 230Th deficit
or excess from each end-member region (bathymetric highs
versus lows; thin versus thick sediment piles) will be
presented. The processes that control this distribution will be
assessed in relation to the present-day 230Th water column
systematics, which we present elsewhere at this conference
(Singh et al.).
Mineralogical Magazine
1401
Geochemistry of antigorite
serpentinite and chlorite harzburgite
from the Cerro del Almirez
(S. Spain): Compositional constraints
on fluids released by dehydration
of mantle serpentinites
C. MARCHESI1*, C.J. GARRIDO1,
J.A. PADRÓN-NAVARTA2, M.T. GÓMEZ-PUGNAIRE2
3
AND V. LÓPEZ SÁNCHEZ-VIZCAÍNO
1
Instituto Andaluz de Ciencias de la Tierra, Granada, Spain
(*correspondence: [email protected])
([email protected])
2
Dpt. of Mineralogy and Petrology, UGR, Granada, Spain
([email protected], [email protected])
3
Dpt. of Geology, University of Jaén, Jaén, Spain
([email protected])
In the Cerro del Almirez massif (Betic cordillera, S.
Spain) hydrous antigorite (Atg)- serpentinite exceptionally
records prograde dehydration to chlorite (Chl)- harzburgite
under eclogite facies conditions (680-710°C and 1.6-1.9 GPa).
Al2O3 contents of Atg-serpentinites and Chl-harzburgites
match those of variable fertile mantle peridotites. SiO2 is
rather higher in some Atg-serpentinites than the values usually
reported for oceanic peridotites, probably owing to
normalization of the whole rock compositions after partial
MgO loss during seafloor weathering.
The REE patterns of Atg-serpentinites are flat or LREEdepleted and show a negative anomaly in Eu. On the other
hand, Chl-harzburgites have ‘U-shaped’ patterns enriched in
LREE and HREE relative to MREE, or are depleted in LREE.
Chl-harzburgites also show negative anomalies in Eu and their
REE concentrations generally coincide with those of Atgserpentinites except for lower abundances in MREE. The
concentrations of lithophile trace elements are usually above
0.1 the values of the primitive mantle and well overlap those
of abyssal peridotites from ocean ridges.
Chl-harzburgites have significantly higher Nb/La, Ta/La,
Zr/Sm and Hf/Sm than precursor Atg-serpentinites. This
indicates that fluids released during the formation of prograde
Chl-harzburgites had complementary low Nb-Ta/LREE and
Zr-Hf/MREE ratios. Zr and HREE concentrations of most
Chl-harzburgites are similar to those of Atg-serpentinites, and
these elements were hence effectively immobile during
deserpentinization. The high Zr/Sm and Hf/Sm ratios of Chlharzburgites are therefore due primarily to the preferential
mobility of MREE into fluids. Additionally, Chl-harzburgites
have also lower Ba/Th than Atg-serpentinites, consistently
with the higher solubility of Ba in fluids compared to Th.
www.minersoc.org
1402
Goldschmidt Conference Abstracts
Low latitude surface ocean
contribution to the deglacial
atmospheric radiocarbon decline
T.M. MARCHITTO1*, S.J. LEHMAN1, C. LINDSAY1,
S.P. BRYAN2, J.D. ORTIZ3 AND A. VAN GEEN4
University of Colorado, Boulder, CO 80309, USA
(*correspondence: [email protected])
([email protected], [email protected])
2
Woods Hole Oceanographic Institution, Woods Hole, MA
02543, USA ([email protected])
3
Kent State University, Kent, OH 44242, USA
([email protected])
4
Lamont-Doherty Earth Observatory of Columbia University,
Palisades, NY 10964, USA
([email protected])
1
The bulk of the atmospheric radiocarbon decline across
the last deglaciation was likely driven by a release of
14
C-depleted CO2 from the deep ocean. Renewed deep mixing
in the Southern Ocean is most often cited as the main
mechanism of that release. However, observations from the
intermediate-depth Indo-Pacific suggest that 14C-depleted
waters were also present at low latitudes during deglaciation.
If those waters impacted the sea surface via upwelling, then
part of the atmospheric #14C drop might be attributable to
radiocarbon isofluxes across the air-sea interface in the tropics
and subtropics.
Here we present new radiocarbon results from two species
of shallow-dwelling planktonic foraminifera in Baja California
core MV99-PC08 (23.5°N, 111.6°W, 705 m water depth).
Calendar ages are estimated by stratigraphic correlation to the
GISP2 ice core in Greenland, allowing us to calculate
seawater #14C through time. We find that the two deglacial
#14C minima previously seen in intermediate waters at this site
are also reflected in the planktonic foraminifera, but in
attenuated form. The rate of decline in Globigerinoides ruber
#14C across Heinrich Stadial 1 was slower than in intermediate
waters, but faster than in the atmosphere. These observations
are consistent with partial upwelling of the #14C minima to the
sea surface. Additional constraint on the vertical transfer is
provided by new benthic #14C data from nearby Soledad Basin
(290 m sill depth). We diagnose the potential impact of low
latitude 14C exchange on the atmosphere using a simple
numerical model of the atmospheric radiocarbon balance.
Mineralogical Magazine
Phases and phase transitions of
tropospheric aerosols
C. MARCOLLI1*, M. SONG1, V.G. CIOBANU1, A. ZUEND2,
G. GANBAVALE1, B. ZOBRIST1, B.P. LUO1, V. SOONSIN1,
U.K. KRIEGER1 AND T. PETER1
ETH Zurich, Institute for Atmospheric and Climate Science,
Switzerland
(*correspondence: [email protected])
2
Department of Chemical Engineering, California Institute of
Technology, Pasadena, California, United States
1
Submicron aerosol particles exert a potentially large but
not well constrained effect on the radiative balance of Earth’s
atmosphere by direct interaction with solar radiation and
indirectly by modifying cloud properties. They typically
consist of a high variety of organic substances, sulfate and
other inorganic ions such as ammonium and nitrate.
Knowledge of the physical state and morphology of these
particles is needed to predict hygroscopicity and gas/particle
partitioning of semivolatile species, to improve knowledge of
heterogeneous and multiphase chemistry, and to quantify light
scattering and absorption.
However, it is difficult to infer the physical state of
atmospheric aerosol particles directly from field measurements. Laboratory experiments on model mixtures and
thermodynamic models are thus required to gain insight into
the phases and phase transitions of aerosols. The high variety
of organic substances impedes crystallization and the organic
fraction remains as a liquid or glass even at low relative
humidty (RH) and cold temperatures. The way this organic
phase interacts with inorganic salts depends on its
hydrophilicity. We use Raman microscopy to investigate the
phase transitions of micrometer-sized particles during
humidity cycles and a high-speed video camera to observe the
efflorescence process. For particles consisting of dicarboxylic
acids and ammonium sulfate, liquid-liquid phase separation
into an organic-rich and an aqueous electrolyte phase occurs
for O:C ratios of 0.7 or lower. Using the thermodynamic
model AIOMFAC (Aerosol Inorganic-Organic Mixtures
Functional groups Activity Coefficients) we can also model
liquid-liquid equilibria and gas/particle partitioning of such
particles. While crystal growth occurs within milliseconds in
the aqueous electrolyte phase, it is drastically slowed in the
highly viscous organic-rich phase. Slow diffusion in glassy
aerosol particles indeed keeps particles off thermodynamic
equilibrium during humidity cycles, as we have shown for
sucrose particles levitated in an electrodynamic balance. This
highlights the need to also consider deviations from
thermodynamic equilibria caused by diffusion limitations
especially at cold and dry conditions.
www.minersoc.org
Goldschmidt Conference Abstracts
Geoneutrino observations and the
Earth energy budget
JEAN-CLAUDE MARESCHAL1, CATHERINE PHANEUF1,
CLAIRE PERRY1 AND CLAUDE JAUPART2
GEOTOP, Université du Québec à Montréal, PO8888, Station
Downtown, Montréal, H3C 3P8, Canada
2
Institut de Physique du Globe de Paris, 1, rue Jussieu, 75238,
Paris Cedex 5, France
1
The total energy loss of the Earth has been calculated to be
46+/-2TW. The heat loss is balanced by the radio-activity of
the Earth’s crust and mantle, the core heat flow and the mantle
secular cooling. The crustal radioactivity is relatively well
constrained (6.5+/1TW), but the uncertainty on all the other
components is very large. Estimates of core heat flow vary
between 5 and 14TW. Mantle cooling could provide between
6 and 18TW. Bulk silicate earth models predict about 13TW
for the heat generation in the mantle, but proposed values of
mantle heat production vary between 9 and 20TW.
Underground neutrino observatories now have the
capability of detecting geo-neutrinos, anti-neutrinos produced
by " decay in radio-elements U and Th series.
It is thus hoped that geoneutrino observations will put
constraints on the abundance and distribution of U and Th in
the mantle and their contribution to the earth’s energy budget.
A small error on the crustal heat generation has a large
impact on the estimates of the abundance of U and Th in the
mantle, because the contribution of the crust to the
geoneutrino flux is 4 to 5 times larger than that of the mantle,.
Combining heat flux and heat production data is the most
robust method to determine with high precision the crustal
radio-activity and to predict the crustal geo-neutrino’s
contribition.
Mineralogical Magazine
1403
Rare earth element (REE)
quantification in geochemical
samples: Can we trust commercially
available ICP-MS calibration
solutions?
E. MARILLO SIALER AND T. MEISEL*
General and Analytical Chemistry, Montanuniversitaet, 8700
Leoben, Austria
(*correspondence: [email protected])
The ICP-MS technique allows the analyses of individual
REE concentrations in a wide range of matrices relevant for
geochemists. However, the quantification of concentrations
via in the mass spectrum still faces complications due to the
vast potential chemical and spectral interferences, arising from
complex sample matrices, when quantification is needed. To
overcome these interferences, a number of measures including
internal standardization, matrix separation, isotope-dilution,
the standard addition method, algebraic correction, among
others, are employed.
In this work we report the results from the isotopic
analysis of fourteen REE in geological materials by ICP-MS.
Three different analytical approaches were studied: 1) ICP-MS
using matrix matched reference materials (RM) for calibration
and 2) HPLC-ICP-MS after Tm addition 3) Isotope Dilution
ICP-MS with and without chemical separation. All approaches
involve sample dissolution by sodium peroxide sintering to
assure complete dissolutions of refractory minerals. The first
analytical procedure for determination by ICP-MS uses
external calibration curves generated from certified and well
characterized, matrix matched geological RM (CRM, provided
and certified by the International Association of Geoanalysts,
IAG) which were prepared in the same way as the studied
samples. The determination by HPLC-ICP-MS comprises
spiking with Tm before sample dissolution and a
straightforward chromatographic matrix separation procedure.
Oxalic and diglycolic acid were used as complexing agents on
a Dionex Ionpac CS5A analytical column. Synthetic standard
solutions obtained from Inorganic ventures, High Purity
Standards and Spex were used for calibration of the HPLCICP-MS.
The findings of this study, and the advantages and
disadvantages of all methodologies used are discussed.
Significant differences between the three calibration strategies
were observed for some of the ICP-MS solutions. Thus the
traceability of the so called certified ICP-MS standard
solutions is questioned and the reliability of the new CRM is
highlighted.
www.minersoc.org
1404
Goldschmidt Conference Abstracts
The diagenesis effect on paleotemperature reconstruction from
Precambrian cherts
JOHANNA MARIN-CARBONNE1,2*,
MARC CHAUSSIDON1 AND FRANCOIS ROBERT3
Universite de Lorraine, CRPG-CNRS 54500 Vandoeuvre les
Nancy, France ([email protected])
2
Department of Earth and Space Sciences, UCLA, CA 90095
USA (*correspondence: [email protected])
3
Laboratoire de Mineralogie et Cosmochimie du Museum,
Museum d’Histoire Naturelle Paris, France
([email protected])
1
Cherts are considered as possible proxies of paleoenvironmental conditions of the Early Earth. Variations in
"18O and "30Si in Precambrian cherts have been used to
reconstruct oceanic temperature [1, 2], and to try to address
the Faint Young Sun Paradox. However, these reconstructions
did not calculate the diagenesis effect, assumed small, on the
isotopic compositions. The in situ ion microprobe study "18O
and "30Si of microquartz in cherts of different ages, from 3.50
Ga to 1.88 Ga, allowed better understanding of the origin and
the formation of these rocks. These results impact the paleotemperatures reconstruction for Precambrian seawater [3].
The correlation between Al2O3 content and "30Si can
discriminate diagenetic cherts from hydrothermal or silicified
cherts. The diagenetic cherts are from the Gunflint Iron
formation (1.88 Ga). These cherts show a typical 2-14 ‰
range for "18O and 2-5 ‰ range for "30Si at the scale of
microquartz grains (~ 2 µm). We interpret this heterogeneity
as inherited from the diagenesis. Hence, these variations could
be explained by a simple model of dissolution-precipitation of
an amorphous silica precursor.
The calculated temperatures from this model ranges from
+37° to +52 °C, suggesting an hot ocean during the
Precambrian Era if Gunflint cherts are representative of global
environment conditions [3]. Taking the diagenesis account
decrease the seawater temperatures found by bulk analysis
previously.
[1] Knauth L.P. Lowe R.D. (1978) Earth & Planetary Science
Letters. 41, 209–222. [2] Robert F. Chaussidon M. (2006)
Nature 443, 969–971. [3] Marin-Carbonne et al. (2010) GCA
74, 116–130.
Mineralogical Magazine
The Manicouagan impact crater:
A site for testing the accuracy of
revisions to the K-Ar system
DARREN F. MARK1 AND LEAH E. MORGAN2
Scottish Universities Environmental Research Centre, East
Kilbride, Scotland, G75 0QF, UK
2
Dept. of Petrology, Vrije Universitiet, De Bolelaan 1085,
1081HV Amsterdam, Netherlands
1
Compared with the U-Pb geochronometer the K-Ar
system still retains relatively large systematic uncertainties.
Recent studies have attempted to improve the accuracy of the
Ar/Ar method by determination of an accurate age for Fish
Canyon sanidine (FCs) [2, 4] and the K-Ar decay constants
[3]. The results vary by 1%, beyond what is expected from
analytical precision. Although the magnitude of this
uncertainty is difficult to assess in single experiments, one can
examine whether the amount of dispersion in the three latest
revisions represent true external reproducibility and thus
reflect geological uncertainties?
Inter-comparison of one Ar/Ar (sanidine) age with one UPb (zircon) age is problematic (e.g. zircon magma residence
time). Sanidine and zircon have markedly different closure
temperatures for the retention of daughter products so we are
commonly faced with the question: what are these minerals
dating and at what level can we assume equivalence?
Melt rocks from large terrestrial impact events are an ideal
target for an Ar/Ar – U-Pb inter-comparison study as they
have a somewhat simple crystallization and cooling history
and do not suffer the protracted crystallization histories that
typify magma-chamber process. Ramezani et al. [1]
determined a high-precision ID-TIMS 206U-238Pb age for
zircon from the Manicouagan impact crater. Here we present a
high-precision Ar/Ar age for the coeval sanidine. We will
discuss revisions to the age of FCs and the K-Ar decay
constants, and show that the latest proposed age for FCs
(Channell et al. 2010) is not consistent with our data. The
approach allows us to get beyond the question of ‘what are we
dating?’ and assess the inter-calibration of the Ar/Ar and U-Pb
chronometers at a level approaching analytical precision.
[1] Ramezani et al. (2005) 19th Goldschmidt Conference
abstract, 321. [2] Kuiper et al. (2008) Science 320, 500–504.
[3] Renne et al. (2010) GCA 74, 5349–5367. [4] Channell et
al. 2010, G-Cubed 11, 1–21.
www.minersoc.org
Goldschmidt Conference Abstracts
Mineralizations monitor depth and
composition variations of
paleohydrothermal fluid systems
Volatile elements in apatite:
An integrated analytical approach
with special focus on bromine
G. MARKL* AND S. STAUDE
Eberhard Karls Universität Tübingen, Wilhelmstrasse 56,
72072 Tübingen, Germany
(*correspondence: [email protected])
More than 1000 hydrothermal mineralizations in the
Schwarzwald ore district of SW Germany formed
discontinuously over the last 300 Ma [1]. Fluid inclusions,
structural and mineralogical specifics allow to distinguish six
different mineralizing fluid systems [2]. Most mineralizations
formed by mixing of a deep-seated and a near-surface fluid.
Interestingly, ore mineral compositions (especially fahlore [3])
and fluid inclusion systematics appear to reflect the relative
importance of the deep and the shallow fluid systems, while
e.g. Sr or Pb isotope systematics allow to quantify their
contributions more precisely in some cases. Stable sulfur,
oxygen and carbon isotope systematics allow to draw
conclusions regarding the source of these (and geochemically
similar) elements.
Combination of these various methods allows to
characterize paleofluid systems with respect to their
composition, their timing and their ore-forming potential in
great detail on a district-wide scale and thereby help to
understand the communication of deep and shallow aquifers
over time in a typical crustal block of 100x50 km size.
[1] Pfaff et al. (2009) Eur. J. Min. 21, 817. [2] Staude et al.
(2009) EPSL 286, 387. [2] Staude et al. (2010) Min. Mag. 74,
309.
Mineralogical Magazine
1405
M.A.W. MARKS1*, M. WHITEHOUSE2, T. WENZEL1,
H. STOSNACH3AND G. MARKL1
Universität Tübingen, 72074 Tübingen, Germany
(*correspondence: [email protected])
2
Swedish Museum of Natural History, Stockholm, Sweden
3
Bruker Nano GmbH, Schwarzschildstrasse 12, D-12489
Berlin, Germany
1
We analyzed a Durango apatite crystal and apatites from
five plutonic samples from the alkaline Mt. Saint Hilaire
Complex (Canada) by means of Electron Microprobe Analysis
(EPMA), Laser Ablation ICP-MS (LA-ICP-MS), Secondary
Ion Mass Spectrometry (SIMS), pyrohydrolysis combined
with ion chromatography, Fourier Transformed Infrared
Spectroscopy (FTIR), Instrumental Neutron Activation
Analysis (INAA) and Total Reflection X-ray Fluorescence
Analysis (TXRF).
The focus of our study are volatile elements (F, Cl, Br, S,
C) with a special emphasis on Br, since the analytical
possibilities for this element are especially in the low- to subµg/g range restricted and thus, reliable concentration data for
Br in rock-forming minerals are scarce. We demonstrate here
that TXRF, which is barely used in geosciences so far, is
suitable for analyzing the bulk content of Br and Cl as well as
of a range of important minor and trace elements (e.g. Sr, Ce,
Fe, Mn, As) in apatite simultaneously. The TXRF method
combines the advantages of low to very low detection limits
(µg/g- to sub-µg/g range), small sample amounts needed (mg
range) and a relatively fast and inexpensive analytical
procedure. In the case of apatite, reliable concentration data
for Br can be produced with detection limits in the sub-µg/g
range. The analysis of Cl is also possible, if a suitable
correction method, which accounts for the observed
systematic underestimation, is applied. For investigations,
where space-resolved data are needed, a large geometry SIMS
machine offers the possibility to analyze F, Cl, Br and S if
reliable data for suitable reference materials exist.
Based on our data, we propose an average Br
concentration of around 0.1 µg/g as a preliminary reference
value for the Durango apatite. However, more data on the Br
content of the Durango apatite are needed in order to validate
this value.
www.minersoc.org
1406
Goldschmidt Conference Abstracts
Endolithic anaerobic methane
oxidation at cold seeps
Elastic properties of nano-crystalline
MgO to high pressures by Brillouin
scattering
JEFFREY J. MARLOW*, JOSHUA STEELE
AND VICTORIA J. ORPHAN
HAUKE MARQUARDT1, ARIANNA GLEASON2,
KATHARINA MARQUARDT1, SERGIO SPEZIALE1,
LOWELL MIYAGI3, GREGOR NEUSSER4,
HANS-RUDOLF WENK2 AND RAYMOND JEANLOZ2
California Institute of Technology, MC 100-23, 1200 E.
California Blvd., Pasadena, CA 91125
(*correspondence: [email protected])
The anaerobic oxidation of methane (AOM) at deep sea
cold seeps has been the target of much work over the last
decade, as researchers have sought to characterize complicated
syntrophic relationships [1], identify metabolically relevant
chemical species [2], and understand the role of AOM in the
broader carbon cycle [3]. However, much of this work has
focused on cold seep sediments, and comparatively little is
known about the associated authigenic carbonates that are
formed as a product of AOM. If biologically active, these
rocks would contribute significantly to AOM processes in the
global deep ocean environment.
Here we describe a unique microscopy and molecular
study of cold seep endolithic environments that compares
sediments, protolithic carbonate nodules, carbonate rocks
associated with active methane seepage (‘active’), and
carbonate rocks from dormant seep areas (‘inactive’). Image
analysis and cell staining with DAPI and domain-specific
CARD-FISH probes showed abundant cell aggregates in all
environments including the interiors of the ‘inactive’
carbonates. Carbonate rocks from active seep habitats
contained the largest and most abundant cell aggregates, with
average diameters around 10 um. 16s rRNA gene sequences
and T-RFLP analyses revealed syntrophic methane oxidizing
archaea and sulfate reducing bacteria, in keeping with
previous studies. X-ray diffraction exposed mineralogical
differences between samples; a relative abundance of metalbased minerals in rock interiors could expose cells to
additional electron acceptors and accommodate larger, more
abundant aggregates.
A quantitative model of methane uptake based on
aggregate density, theoretical enzyme kinetics, measured
methane concentrations, and carbonate rock porosity will be
presented to demonstrate the role of carbonate pavements in
overall methane consumption. The finding of active endolithic
AOM consortia expands our understanding of where and how
AOM occurs, suggesting that a significant – possibly
dominant – component of AOM activity in cold seep habitats
may occur within lithified carbonates at and within the seabed.
[1] Orphan et al. (2002) PNAS 99, 7663–7668. [2] Beal, E.J.
et al. (2009) Science 325, 184–187. [3] Reeburgh, W.S. (2007)
Chemical Reviews 107, 486–513.
Mineralogical Magazine
German Research Center for Geosciences (GFZ),
Telegrafenberg, 14473 Potsdam, ([email protected])
2
Department of Earth and Planetary Science, University of
California, Berkeley, CA 94720
3
Geology and Geophysics Department, Yale University, P.O.
Box 208109, New Haven, CT 06520
4
Institute for Geological Sciences, Freie Universität Berlin,
12249 Berlin, Germany
1
Recent Brillouin scattering results on the sound wave
velocities of MgO powder compressed under non-hydrostatic
conditions show velocities that are around 20% lower than
expected from single-crystal data [1]. These results question
the reliability of Brillouin scattering of polycrystalline
materials and they illustrate that several poorly understood
processes might affect the derived sound wave velocities,
including a preferred orientation of the crystallites (texturing),
non-hydrostatic conditions in the diamond-anvil cell, and
grain size effects.
Here, we report the elastic properties of nano-crystalline
MgO powder determined by Brillouin scattering to pressures
above 30 GPa. We find the acoustic velocities to be
significantly lower than reported data on single-crystal MgO.
A careful characterization of the crystallite sizes in our sample
material by synchrotron x-ray diffraction and high-resolution
scanning and transmission electron microscopy shows that the
average crystallite size stabilizes at about 7 nm at high
pressures. The small crystallite size has a profound effect on
the elastic properties and is responsible for the observed low
velocities in MgO. We show that this effect prevails at high
pressures.
Based on our first data analysis, zero-pressure bulk and
shear moduli of the intercrystalline material (mostly grain
boundaries) are reduced by about 70 % and 80 %,
respectively, as compared to the crystalline material. The
effect of grain size on the measured velocities is by far
exceeding any effects of non-hydrostaticity and texturing. Our
findings imply that a thorough characterisation of the
crystallite size distribution is crucial for the interpretation of
Brillouin scattering results from polycrystalline materials.
[1] Gleason et al. (2011) GRL 38, L03304.
www.minersoc.org
Goldschmidt Conference Abstracts
Synchrotron X-ray diffraction of
nano-crystalline MgO Powder to
65 GPa
HAUKE MARQUARDT , SERGIO SPEZIALE ,
HANS JOSEF REICHMANN1
2
AND HANNS-PETER LIERMANN
1
1
German Research Center for Geosciences (GFZ),
Telegrafenberg, 14473 Potsdam ([email protected])
2
DESY, PETRA III, Notkestr. 85, 22607 Hamburg
1
The compression behavior of nano-crystalline materials
(crystallite sizes smaller than 100 nm) might significantly
differ from the behavior of larger grained materials.
We compressed MgO powder with an average crystallite
size of about 20 nm in a diamond-anvil cell. The sample
material was loaded either with or without a pressuretransmitting medium. Our results indicate that the crystallite
size is preserved in the quasi-hydrostatic experimental run,
whereas it reduced to below 10 nm in the non-hydrostatic
experiment.
High-pressure synchrotron x-ray diffraction was
performed at DESY/PETRA III beamline P02.2 using an
energy of about 42.8 keV, a focusing spot of ~2 x 2 µm2, and a
collection time of 30-60 seconds. Up to nine diffraction lines
could be detected at high-pressures.
Our results that were collected in hydrostatic conditions
indicate that the zero-pressure bulk modulus is slightly
decreased as compared to large-grained MgO [1], but both
zero-pressure volume and zero-pressure derivative of the bulk
modulus are unaffected within the experimental uncertainties.
The material that was non-hydrostatically compressed appears
to be less compressible compared to the same (starting)
material that was quasi-hydrostatically pressurized. The
compression behaviour in this run is, however, likely also
influenced by a continuous crystallite size reduction and the
consequent increase of the volume fraction of intercrystalline
material in the sample, that occurs upon compression in nonhydrostatic conditions.
1407
Focused ion beam cutting of large
samples for Brillouin spectroscopy
KATHARINA MARQUARDT AND HAUKE MARQUARDT
German Research Center for Geosciences (GFZ),
Telegrafenberg, 14473 Potsdam ([email protected])
Brillouin spectroscopy is a major technique for the
determination of elastic properties of single-crystals at highpressures and high-temperatures. Brillouin scattering at
extreme conditions is usually carried out in symmetric platelet
forward scattering geometry, which allows for a
straightforward evaluation of shear and compressional
velocities. However, well-polished platelet samples with
parallel faces are required. Mechanical polishing is restricted
to materials of sufficient size and mechanical stability. This
precludes the preparation of a number of compounds with
significant geophysical relevance, including both natural
samples and candidate Earth materials that are synthesised at
high-pressure/high-temperature conditions (for instance
ferropericlase, perovskite).
Here, we show that ion cutting and polishing is a very
elegant approach to prepare µm-sized samples of well-defined
thickness with high surface quality. It does not expose the
samples to mechanical forces, thus allows for preparing
materials that are brittle, meta-stable, or show a strong
cleavage. In addition, it offers the chance to cut more than one
sample from a piece of material, for instance two platelets
with different orientation from one single-crystal (fig. 1). A
transmission electron microscopy (TEM) foil can be produced
simultaneously. This allows for a detailed characterization,
including chemical composition, crystallographic orientation,
defect structure and secondary phases, of the same sample
material, i.e. the same single-crystal, that is later used for
optical spectroscopy.
We successfully tested this method on different
geomaterials, including perovskite, ferropericlase, spinel, and
antigorite.
[1] Speziale et al. (2001) JGR 106, 515–528.
#
#
Figure 1: Secondary electron images of a perovskite singlecrystal platelet that was cut from an aggregate made up of
several single-crystals. The platelet, with approximate
dimensions of 180 x 180 x 30 µm3, was double-side polished
(left). The platelet was manually flipped by 90° and again
inserted into the dual beam machine (right). Several samples
were cut for Brillouin spectroscopy, single-crystal x-ray
diffraction and TEM analysis.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
1408
Geochemistry and mineralogy of
volcanic ash red paleosol from Fogo
island (Cape Verde)
R. MARQUES1,3, M.I. PRUDÊNCIO1,3,
J.C. WAERENBORGH1, F. ROCHA2,3,
M.I. DIAS1,3 AND E. FERREIRA DA SILVA2
Instituto Tecnológico e Nuclear, EN 10, Sacavém, Portugal
2
Dep. Geociências, Univ. Aveiro, Aveiro, Portugal
3
GeoBioTec, Univ. Aveiro, Aveiro, Portugal
1
Introduction
Red paleosols developed on volcanic ashes occur in Fogo
island (Cape Verde, semi-arid climate). Four samples were
collected in a vertical profile (70 cm depth) of paleoweathered
volcanic ashes (Monte Almada, western Fogo) with
decreasing grain size upwards and varying in colour: P1-1dark gray + dark reddish brown; P1-2 – dark yellowish brown
+ yellowish brown; P1-3 – red; and P-4 – weak red at the top.
The paleosol is underlayed by carbonatite and covered by
nephelinite lavas. Chemical and mineralogical analyses were
done by INAA, Mössbauer spectroscopy and XRD.
Figure 1: Chemical variations with depth.
Discussion of Results
A general decrease of the analysed chemical elements
(rare earth elements included) occur in the upper levels (Fig.1,
where sample P1-1, collected at the bottom, was used as
reference). Exceptions were found for Cr and Zn. Na is
enriched at the top level. Quartz, augite and phyllosilicates are
ubiquitous. Magnetite is present in the lower P1-1 and P1-2
levels and gradually oxidizes towards maghemite in P1-3 and
P1-4. Hematite is observed in all samples, its content
increasing upwards. Fe2+ is incorporated in phyllosilicates and
augite throughout the profile. The Fe2+/Fe3+ ratio is slightly
lower in the surface level.
Mineralogical Magazine
Horozontial and vertical water mass
tracing of the SW Pacific Ocean
during the last deglaciation
J.P. MARR1, J.A. BAKER1, L. CARTER1, A. ALLAN1,
K. CHRISTENSEN1 AND H.C. BOSTOCK2
Victoria University of Wellington, Wellington, New Zealand
(*correspondence: [email protected])
2
National Institute of Water and Atmospheric Research,
Wellington, New Zealand
1
We have measured Mg, Al, Mn, Zn, Sr and Ba/Ca ratios
for Globigerina bulloides by LA-ICPMS, in a high-resolution
marine
sediment
core
(MD97-2121,
40°22.935"S;
177°59.68"E; 25 ka to present) from the SW Pacific Ocean at
centennial scale resolution. The core site resides beneath two
major, interacting surface water masses (Subtropical Water
[STW], Sub-Antarctic Water [SAW]). Mg/Ca ratios record a
change in mean ocean temperature of 6°C from the last glacial
period to the Holocene, with a maximum regional temperature
difference of 11°C. Alkenone paleo-ocean temperatures from
the same core record significant differences with an earlier (2
kyr) onset of deglaciation, subdued short-term temperature
variability and do not define the Antarctic Cold Reversal,
which is clearly visible in the Mg/Ca record. Mg/Ca ratios in
the final (f) and antepenultimate (f-2) chamber of G. bulloides
appear to reflect its migration through the water column at
differing stages of its life cycle. Holocene Mg/Ca values have
a 20% difference between chambers f and f-2 compared to
10% during the last glacial period, suggesting a reduction in
the glacial surface ocean thermal stratification. Measurement
of Mn, Ba and Zn in G. bulloides from a regional suite of
core-tops potentially discriminates STW and SAW. The
down-core results demonstrate a dominance of SAW during
the last glaciation when enhanced winds forced northward
transport of surface waters, accompanied by increased
upwelling, and a prominence of STW during the Holocene.
www.minersoc.org
Goldschmidt Conference Abstracts
Controls on modern and paleo-shell
weights of G. bulloides in the SW
Pacific Ocean
JULENE MARR, ANNETTE BOLTON,
KYLIE CHRISTIANSEN,
JOEL BAKER* AND LIONEL CARTER
Victoria University of Wellington, P.O. Box 600, Wellington,
New Zealand (*correspondence: [email protected])
Shell weights of the planktic foraminfera G. bulloides
have been used to track changes in near-surface ocean
carbonate ion concentrations over the past 50 kyr in the
Atlantic Ocean [1], and to hypothesize that anthropogenic
atmospheric CO2 increases and ocean acidification resulted in
decreases in modern G. bulloides shell weights as compared to
mean Holocene weights in the Southern Ocean [2]. We have
carried out a study of the test sizes and weights, and trace
element chemistry of ‘modern’ G. bulloides in sediment coretops from the SW Pacific Ocean (latitudes 33-53°S; T=719°C). Mean size-normalized shell weights (SNW) correlate
negatively with near-surface ocean temperature in the SW
Pacific Ocean (T = 31.8 x e -30.5 x SNW) and, unlike the study of
[1], shell weights are heaviest in southernmost sites of lowest
temperatures and lowest carbonate ion concentrations. Similar
suites of data have been obtained for G. bulloides from sites
offshore of eastern New Zealand for the past 25 kyr covering
the last deglaciaton, and MIS-33 to MIS-29 encompassing the
warm MIS-31 interglacial when collapse of the Ross Ice Shelf
and substantive ice loss from West Antarctica may have
occurred [3]. Hypothetical G. bulloides SNW can be
calculated for these paleo-records using the modern
relationship between ocean temperature and SNW, Mg/Ca
paleo-ocean temperatures, and then compared with measured
SNW. In the current interglacial (<10 kyr) and the MIS-29
interglacial, measured SNW are in good agreement (within
10%) of predicted values. However, during the last and MIS30 glacial periods, measured SNW are often more different
(up to 30%) than predicted SNW, although the modern ocean
temperature-SNW relationship is still the prominent control on
SNW. During and prior to MIS-31, measured SNW deviate
significantly (up to 100%) from predicted vaues and, in fact,
correlate positively with Mg/Ca paleo-ocean temperatures and,
presumably, are largely controlled by carbonate ion
concentrations. These results demonstrate the complexity in
attributing changes in G. bulloides SNW to one process both
in different ocean settings and also back in time at a single site
in the SW Pacific Ocean.
Water dynamics in clay as a function
of temperature: Coupling Neutron
Spin Echo and molecular dynamics
V. MARRY1*, E. DUBOIS1, N. MALIKOVA2, M. SALANNE1,
S. LONGEVILLE2, W. HAUSSLER3 AND J. BREU4
Univ Pierre et Marie Curie – Paris 6, UMR-UPMC-CNRSESPCI 7195, Case 51, 4 Place Jussieu, 75252 Paris,
France (*correspondence: [email protected])
2
Laboratoire Léon Brillouin, UMR CEA-CNRS 12, CEA
Saclay, 91191 Gif-sur-Yvette, France
3
FRM-II & E21, Technishe Universität München,
Lichtenbergstrasse 1, 85747 Garching, Germany
3
Institut für Anorganische Chemie, Universität Regensburg,
93040 Regensburg, Germany
1
In the context of underground storage of radioactive
waste, investigating water molecules dynamics in swelling
clays considered in engineered barriers is of prime importance.
In the vicinity of the canisters containing the nuclear waste,
the temperature can reach more than 350K. Swelling clay
minerals are lamellar alumino-silicates with permanent
negative charge compensated by exchangeable cations situated
between clay layers. In contact with water, the cations hydrate,
leading to the formation of one, two or more layers of water
confined between clay surfaces.
We study the translational dynamics of water in clays in
low hydrated states by coupling quasi-elastic neutron
scattering experiments (Neutron Spin Echo or NSE) and
molecular dynamics (MD) on a large scale of temperature
range where water remains liquid. As the natural
montmorillonite clay of interest is complex to analyze because
of interstratification, we chose to model it by a synthetic clay
with well-defined states of hydration [1]. The activation
energies of the diffusion processes determined by NSE are
around 6 kJ/mol higher than for bulk water, for both the
hydration states studied. The simulations are found to be in
good agreement with experiments for relevant set of
conditions [2] and they allow more insight into the origin of
the observed dynamics, like the influence of hydrogen
bonding and specific interactions with the surfaces.
[1] Malikova,N. et al. (2007) J. Phys. Chem. C 111, 17603–
17611. [2] Marry,V. et al. (2011) Environ. Sci. Technol. 45,
2850–2855.
[1] Barker & Elderfield (2002) Science 297, 833–836. [2] Moy
et al. (2009) Nature Geoscience 2, 276–280. [3] Pollard &
deConto (2009) Nature 458, 329–332.
Mineralogical Magazine
1409
www.minersoc.org
1410
Goldschmidt Conference Abstracts
Competition between lanthanides and
Al for humic acid binding
Recycling agents in subduction zones:
Fluids, melts and solids!
Geosciences Rennes, Rennes 1 Univ., UMR 6118 CNRS,
France (*correspondence: [email protected])
1
R. MARSAC*, M. DAVRANCHE, G. GRUAU AND A. DIA
Lanthanides or rare earth elements (REE) are commonly
studied as analogues of actinides. This group of 14 elements
present a unique feature related to their similar and coherent
chemical properties. In natural waters, REE aqueous
concentrations and transport is strongly affected by dissolved
organic matter such as humic acids (HA). However, in
organic-rich waters, different REE concentration patterns are
observed. A first explanation is the heterogeneity of HA
binding sites: REE-HA pattern is the fingerprint of the
dominant REE binding HA sites. Previous study showed that
light REE (LREE) are more bound to HA carboxylic sites
whereas heavy REE (HREE) are more bound to HA phenolic
sites. Secondly, in natural waters, various cations are also
bound to HA and might therefore affect REE-HA binding and
subsequent pattern. Al is one of the major competitor cation
for REE regards to its high affinity for HA and it strong
concentration in natural waters.
Al-REE competition experiments for HA binding were
performed between pH 3 and 6. Results were modelled with
Model VI, a specific humic-ion binding model. It appeared
that Al3+ and Al(OH)2+ present the same affinity for HA sites
as already assumed in Model VI. However, Al3+ and Al(OH)2+
are stronger competitors for HREE than LREE, which is not
expected in the model and was attributed to Al strong affinity
for HA phenolic groups. From pH 5 to 6, Al competitive effect
decreases because of Al(OH)3 precipitation. However, Al
becomes more competitive for LREE than HREE regards to
the Al(OH)2+ binding to HA carboxylic groups. Model VI
parameters were re-evaluated and, for the first time, Al(OH)2+
was also considered to bind to HA. The new set of Al
parameters improved model accuracy for both our REE-Al
competitive experiments and Al-HA data from literature.
REE-Al competitive study for HA shows a new Al-HA
binding mechanisms which was not observed before. These
results highlight the strong impact of competitor cations on the
REE-HA binding behaviour in natural organic-rich waters.
This study provides a more accurate description of Al-HA
binding and, therefore, will indirectly improve REE and
actinides speciation modelling in environmental systems.
Mineralogical Magazine
HORST R. MARSCHALL1 AND JOHN C. SCHUMACHER2
Dep. of Geology & Geophysics, WHOI, Woods Hole, MA
02543, USA, ([email protected])
2
Dep. of Earth Sciences, University of Bristol, Bristol BS8
1RJ, UK, ([email protected])
Sediment melts and hydrous fluids loaded with solutes
generated in the subducting slab at elevated P-T conditions are
thought to transport differing amounts of trace elements and
variable isotopic signatures from the subducting slab into the
overlying mantle, where they ultimately contribute to the
source region of magmas produced at convergent plate
margins. Conventional geochemical models of subduction
zones consider trace elements to be derived from two distinct
sources: hydrous fluids derived from altered oceanic crust
during subduction and partial melts derived from the thin
sedimentary veneer. However, the physical processes of
transport and mixing of these contributors within the
subduction factory are largely enigmatic.
Studies on exhumed subduction mélanges suggest that
hybrid rocks with newly grown minerals concentrate,
sequester and redistribute water and key trace elements [1, 2].
The strong petrologic and chemical contrast at the slab-mantle
interface, produces these hybrid rock compositions by
metasomatic reactions, diffusion and mechanical mixing: the
Al-, Si- and alkali-rich slab that carries crustal isotopic
signatures and trace-element abundances is juxtaposed with
the Mg-rich ultramafic rocks of the harzburgitic mantle.
Mechanical mixing of crustal and mantle rocks will propagate
the formation of hybrid rocks, and fluxing by hydrous fluids
derived from the dehydrating slab will enhance reactivity and
lead to fluid saturation of the newly formed rocks.
The identification of cold plumes in high-resolution
numerical experiments [3] provides a mechanism to transport
buoyant hybrid rocks from the slab-mantle interface towards
the source region of arc magmas. Mélange rocks travelling
into the mantle wedge in ‘wet’ diapirs would be subjected to
P-T conditions dramatically different from those at the slab
surface. Partial melting of hybrid rocks may produce the large
range of major and trace-element compositions found in
modern island arc volcanic rocks.
[1] Bebout & Barton (2002) Chem. Geol. 187, 79–106.
[2] Miller et al. (2009) Lithos 107, 53–67. [3] Zhu et al.
(2009) G-cubed 10, Q11006.
www.minersoc.org
Goldschmidt Conference Abstracts
Erosion monitored by riverine
sediment Ti-in-quartz, Southern
Alps, New Zealand
Contribution of groundwater to
chemical weathering fluxes in the
Pingtung Plain, Taiwan
C.E. MARTIN*, K.B. MCKERCHER AND J.M. PALIN
CAROLINE MARTIN1*, ALBERT GALY1, NIELS HOVIUS1,
MIKE BICKLE1, IN-TIAN LIN2, MING-JAME HORNG3,
DAMIEN CALMELS4, HAZEL CHAPMAN1 AND
HONGEY CHEN5
Dept. of Geology, Univ. of Otago, P.O. Box 56, Dunedin 9054
NZ (*correspondence: [email protected])
Quartz is an abundant mineral in the surface environment,
and can have as its source a variety of primary and recycled
sources. Recent developments have shown that Ti
incorporation into quartz is proportional to crystallization
temperature, pressure, and a (TiO2) [1, 2]. We have explored
the use of Ti and other trace elements as a fingerprint of the
source of quartz sediment in rivers draining the actively
uplifting and eroding Southern Alps of New Zealand.
The Haast River drains the western side of the Southern
Alps and experiences very high rainfall and erosion rates. The
bedrock schist within the catchment exhibits a metamorphic
field gradient from chlorite through garnet-oligoclase zone.
Quartz in these rocks have Ti concentrations that reflect
prograde re-equilibration of detrital grains and crystallization
of new quartz in the presence of ilmenite or titanite at
appropriate pressures [3].
Sediment was collected along the length of the river
system and sieved to obtain grain size fractions. Quartz grains
from each size fraction were mounted in epoxy, polished and
analyzed by LA-ICP-MS. Raw intensity data were normalized
via analyses of the NIST 610 standard to obtain trace element
concentrations. Ti-in-quartz temperatures [1, 2] were
calculated using estimated pressure and a (TiO2) for the schist
bedrock.
Quartz sediment shows changes in trace element
concentrations and Ti-temperature with location that reflect
the metamorphic grade of the upstream bedrock. Several
samples exhibit smooth variations with grain size. Bulk
chemistry and mineralogy of bedload sediment have
previously shown that physical erosion dominates over
chemical weathering processes in the Haast River catchment
but were unable to discriminate the bedrock sources [4]. Our
results for the Haast River indicate that Ti-in-quartz can be a
sensitive provenance tracer for sand; we are currently
analyzing quartz sediment from other active river systems and
sedimentary basins on the South Island in order to assess the
robustness of the method.
[1] Wark & Watson (2006) Contrib. Min. Petrol. 152, 743–
754. [2] Thomas et al. (2010) Contrib. Min. Petrol. 160, 743–
759. [3] Palin et al. (2011) MinMag, this volume. [4] Kautz &
Martin (2007) Appl. Geochem. 22, 1715–1735.
Mineralogical Magazine
1411
Dept. Earth Sciences, University of Cambridge
(*correspondence: [email protected])
2
Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan
3
Water Resources Agency, Ministry of Economic Affairs,
Hsin-Yi Road, Taipei, Taiwan
4
Institute de Physique du Globe, Paris, France
5
Dept. of Geosciences, National Taiwan University
1
The concentration of dissolved cations in flowing
groundwaters of the Pingtung Plain gravel, sand and clay
aquifer systems in southwest Taiwan demonstrates that
underground circulation is a significant source of major and
trace ions to the ocean for Taiwan, comparable in magnitude
to the weathering flux measured in the surface runoff of the
Pingtung Plain in the Kaoping River. The waters from 33
wells at varying depths through a 280 m window in the plain
were analysed for cations: Ca2+, Mg2+, Na+, K+, Sr2+, Fe2+ and
Ba2+, and anions: Cl-, SO42- and NO3-, and compared with a 5year bi-weekly time series from the Kaoping River. Multi-year
hydrological head data gives the direction of groundwater
flow through the drilled depth of the basin, and indicates that
pumping of the aquifer for irrigation and fish farming has had
a limited effect on the hydrological stability of the system.
Hydraulic conductivities for each well location show that
hydrological connectivity exists throughout the drilled depth
of the basin whereas chemical gradients suggest that stratified
flow is in operation. At the proximal position of the
groundwater flow paths, the concentration of dissolved species
in the groundwater ranges from 1.1 to 3.3 times that of the
Kaoping River; increasing to 2.3 to 8.5 times the Kaoping
River values at the coastal region of the aquifer, indicating that
net chemical weathering occurs along subsurface flow
pathways. When compared to the 5-year time series for the
Kaoping River, the relative contribution of subsurface fluxes
is between 40 to 50% for Na, K, Sr, Ca and around 30% for
Mg and SO4. The results suggest submarine groundwater
discharges in the Taiwan strait and that the impacts of
groundwater from active margins on global ocean
geochemcial budgets need to be much better constrained.
www.minersoc.org
Goldschmidt Conference Abstracts
1412
Nd and Hf model ages in the Western
Gneiss Region, Norway: A new way
to better understand mantle-crust
evolution
CÉLINE MARTIN1,2, STÉPHANIE DUCHÊNE1,3,
BÉATRICE LUAIS1 AND ETIENNE DELOULE1
CRPG, Nancy-Université, CNRS, 15 rue Notre Dame des
Pauvres 54501 Vandoeuvre les Nancy cedex
2
present adress: DGLG – WE - Vrije Universiteit Brussel,
Pleinlaan, 2 B-1050 Brussels
3
present adress: LMTG, UMR 5563, CNRS - UPS Toulouse
III - IRD, 14 rue Edouard Belin, 31400 Toulouse
1
The signification of Hf model ages is revisited through the
study of metabasites and their gneissic host-rock of
Vårdalsneset (Western Gneiss Region, Norway), with the
comparison of Nd and Hf model ages, that are assumed to be
similar for a given sample.
Three different mantle-crust differentiation models
currently exist on the basis of Nd and Hf isotope systematics:
(i) the canonical model with chondritic Earth and an unique
early step of differentiation, (ii) a model with chondritic Earth
and a continual growing crust since 3 Ga and (iii) a model
with sub-chondritic Earth and a continual growing crust since
4.56 Ga, and they remain to debate. It is therefore expected
that Nd and Hf model ages calculations could allow the
validation of one of these models.
Rock protoliths as well as trace-element mobility are
characterized by a petrological and geochemical study.
Metabasic samples likely came from cumulates and MORBtype basalt whereas gneiss could represent paragneiss and not
orthogneiss as usually accepted in the WGR of Norway.
As the trace elements appear slightly mobile, the Nd and
Hf isotopic data enable to calculate model ages.
Interestingly, whatever the crust-mantle differentiation
model used, Nd model ages are equal within error contrarily to
Hf model ages (Table 1).
min
max
Nd (i)
1.44±0.35
1.87±0.02
Hf (i)
2.18±0.39
3.21±0.52
Nd (ii)
1.16±0.30
1.44±0.06
Hf (ii)
1.44±0.38
1.97±0.78
Nd (iii)
1.09±0.34
1.31±0.04
Hf (iii)
1.22±0.39
1.56±0.38
Table 1: Nd and Hf model ages in Ga calculated on
metabasites for the three mantle-crust differentiation model.
We assume that both Nd and Hf model ages should be in
agreement with metabasites zircon U-Pb age (1.15 ± 0.20 Ga).
Thus, we show that only the third model with sub-chondritic
Earth and a continual growing crust since 4.56 Ga allows to
obtain significant model ages with both Nd and Hf isotopic
systems ranging from 1.09 ± 0.34 to 1.56 ± 0.38 Ga.
Mineralogical Magazine
Pb isotopic history of weathering on
Antarctica during the EoceneOligocene transition
ELLEN E. MARTIN1 AND CHANDRANATH BASAK
Dept. of Geological Sciences, Univ. of Florida, Gainesville,
Fl 32611, USA ([email protected], [email protected])
The initiation of Antarctic continental glaciation at the end
of the Eocene is one of the most dramatic climate events in the
Cenozoic. Drawdown of atmospheric CO2 below a threshold
value is considered one of the prerequisites for this glacial
transition, suggesting a possible role for silicate weathering. In
this study we compare Pb isotopes recorded in Hydroxylamine
Hydrochloride extractions (seawater) and residual terrigenous
material from two intermediate water, circum-Antarctic sites
(ODP Sites 689 and 738) to evaluate the extent of chemical
weathering and the composition of weathered material during
the Eocene/Oligocene transition (EOT). Prior to the EOT,
seawater and residues record similar 206Pb/204Pb, 207Pb/204Pb
and 208Pb/204Pb values. At the EOT, both sites record
increasing seawater and residue 207Pb/204Pb and 208Pb/204Pb
values, with some structure apparent in the higher resolution
record of Site 738 that matches the two-step glacial transition
defined by "18O. In contrast, 206Pb/204Pb values for seawater
become more radiogenic at both sites, while values for
residues become less radiogenic.
The similarity between seawater and residue values for all
three Pb isotopic systems suggest extensive, congruent
chemical weathering that may have started during the warm
Eocene, an interpretation supported by other proxies.
Variations in residue Pb isotopes starting at the EOT imply
intensified mechanical weathering that incorporated multiple
silicate source rocks with different chemical compositions.
This interpretation is consistent with the idea that the glaciers
weathered rocks from a broader region as they grew. The fact
that seawater Pb isotopic values track residue values argues
that the silicate mechanical weathering products from the
glaciers were exposed to active chemical weathering and
controlled the local seawater Pb isotopic signal. This silicate
weathering could have contributed to the drawdown of
atmospheric CO2. The correlation with the "18O two-step also
implies that intervals of cooling and ice growth were
associated with weathering pulses. The pattern for 206Pb/204Pb
values is distinct from the other two isotopic systems after the
EOT and is interpreted to represent weathering of Phanerozoic
carbonates that contribute uranogenic, but not thorogenic, Pb.
Weathering inputs from these carbonate source rocks may
have contributed to deepening of the carbonate compensation
depth.
www.minersoc.org
Goldschmidt Conference Abstracts
1413
Experimental determination of
CO2/H2O in subduction zone fluids by
GC-TCD analysis
Influence of different sources on
cloud condensation nuclei numbers in
the high Arctic
Research School of Earth Sciences, The Australian National
University, 0200 Canberra ([email protected])
2
Research School of Earth Sciences, The Australian National
University, 0200 Canberra ([email protected])
1
LAURE A.J. MARTIN1 AND JOERG HERMANN2
1
Carbon recycling in subduction zones plays an important
role in the evolution of climate through geological time and in
the formation of diamonds in the deep mantle. Carbonates
formed during seafloor alteration of the oceanic crust are
buried into the deep Earth along subduction zones.
Experimental studies on the phase stability in H2O-CO2bearing basaltic compositions indicate that the fluid at sub-arc
depth is dominated by H2O [1]. However, experimental studies
are hampered by the difficulty to estimate accurately the
H2O/CO2 of the fluid in the experimental products.
We conducted experiments with a starting material made
of a synthetic K2O, CO2 and H2O-bearing basaltic composition
between 3.0 and 3.5 GPa, 700 - 775°C in a piston-cylinder
apparatus. The experimental results indicate that the solidus
occurs between 700 and 750°C at both 3.0 and 3.5 GPa. At
T'750°C, dolomite and magnesite coexist with garnet,
omphacite, phengite, epidote, coesite, rutile ± kyanite. At
T%750°C, Mg-calcite±dolomite coexist with melt, garnet,
omphacite, epidote, rutile ± coesite and phengite.
The experimental capsules have been pierced under
vacuum and the experimental gas, mixed with pure He, has
then been directly analysed with an Agilent Technologies
6850 gas chromatograph equipped with a thermal conductivity
detector (GC-TCD). The accurate determination (±5%) of
small quantities of CO2 and H2O in a He mixture by GC-TCD
method has been validated in using pure standards of these gas
and the elaboration of the calibration lines between their
partial pressures in a He mixture versus the peak area read in
the chromatograms. PCO2/PH2O of the gas mixture in
equilibrium with the sub-solidus assemblages decreases with
pressure from 6.3 to 4.0, confirming the previous estimations
of low CO2 contents in such aqueous fluids [1]. The gas
mixture released from experiments above the solidus is
characterised by PCO2/PH2O ranging from 6.1 to 3.6. This
indicates that some H2O and CO2 are released from the glass
during quenching. Therefore, analyses of the glass and the
quench fluid are needed in order to quantify the CO2 release
during partial melting of altered oceanic crust.
[1] Poli et al. (2009) EPSL 278, 350–360.
Mineralogical Magazine
M. MARTIN1*, B. SIERAU1, C. LECK2 AND U. LOHMANN1
ETH Zurich, Institute for Atmospheric and Climate Science,
Universitätsstr. 16, 8092 Zurich, Switzerland
(*correspondence: [email protected])
2
Department of Meteorology, Stockholm University,
Stockholm, Sweden
Introduction
A thin cloud layer is often observed in the high Arctic in
summer. The sources of particles in this region that act as
cloud condensation nuclei (CCN) can be long-range transport
from continental sources, but also primary particles emitted
from the Central Arctic Ocean including the pack ice area, and
secondary formed from local sources or transported precursors
might contribute.
The ASCOS (Arctic Summer Cloud Ocean Study)
campaign on board an icebreaker was undertaken into the high
Arctic in summer 2008 to investigate aerosol properties.
Measurements from two CCN counters are presented.
Results and Discussion
CCN properties were analysed and classified based on
different meteorological conditions, and CCN number
concentrations were correlated with different air mass source
regions. The CCN concentration and the activated fraction was
very variable throughout the campaign.
Figure 1. Measured CCN concentration at 0.10 and 0.73%
supersaturation as a function of the number of days the air
spent over the ice.
The data was also investigated using the time, which the
air masses spent over the pack ice before reaching the ship
(see Fig. 1). High concentrations after a few days over the ice
can be taken as a hint for local particle sources.
www.minersoc.org
Goldschmidt Conference Abstracts
1414
Which is more ionic?
UO2 or PuO2
RICHARD L. MARTIN
Theoretical Division, Los Alamos National Labnoratory, Los
Alamos, NM ([email protected])
The electronic structure of many of the oxides containing
d- and f-elements has long been a challenge for theory. For
example, the traditional workhorses of density functional
theory, the local density approximation (LDA) and the
generalized gradient approximations (GGA), predict most of
these systems to be metallic, when in fact they are insulators
with band gaps of several eV. These problems reflect the
localization/delocalization dilemma faced in systems with
weak overlap and seem to be largely overcome by the new
generation of hybrid density functionals developed for
molecular studies. Only fairly recently has it been possible to
apply these functionals to solids but in the cases studied thus
far we find a distinct improvement when comparing with
experiment. Hybrid functionals have also made a
counterintuitive prediction: that of significant covalency in
PuO2, as opposed to UO2; a prediction that has now been
addressed by experiment. I will review predictions of the
theory and recent experimental work on the first single-crystal
quality samples of PuO2.
Mineralogical Magazine
Covalency in the actinides probed
with ligand K-edge X-ray absorption
spectroscopy
RICHARD L. MARTIN AND ENRIQUE R. BATISTA
Theoretical Division, Los Alamos National Laboratory, Los
Alamos, NM 87544 ([email protected], [email protected])
I will discuss experimental and theoretical investigations
of ligand K-edge X-ray absorption spectroscopy for a number
of actinide complexes and solids. Evidence for f-orbital –
ligand bonding interactions will be presented, and the
ramifications of this for actinide electronic structure discussed.
www.minersoc.org
Goldschmidt Conference Abstracts
Corals constrain CaCO3 chemistry at
the Triassic–Jurassic boundary, a
potential ocean acidification event
ROWAN C. MARTINDALE, WILLIAM M. BERELSON,
FRANK A. CORSETTI, DAVID J. BOTTJER
AND A. JOSHUA WEST
University of Southern California, Los Angeles, USA
([email protected], [email protected], [email protected],
[email protected], [email protected])
Ocean acidification associated with emplacement of the
Central Atlantic Magmatic Province (CAMP) has been
suggested as a kill mechanism for the Triassic–Jurassic (T–J)
mass extinction (~200Ma), but few direct proxies for ocean
acidity are available in the Mesozoic. In this work, we show
that the presence of corals and reefs in the fossil record can
provide a proxy for saturation state, and we use this proxy to
determine the plausibility of an acidification event at the T-J.
The new proxy for surface aragonite saturation (4Arag)
proposed here uses the physiological constraints of modern
corals to determine minimum 4Arag during the intervals when
coral are preserved in the fossil record. Corals lose the ability
to biomineralise below aragonite saturation (4Arag) of 2 and
coral reefs are restricted to 4Arag > 3, so when scleractinians
are preserved in the rock record, surface ocean 4Arag was > 2,
and when coral reefs are preserved, 4Arag > 3. Coral reefs are
preserved throughout the latest Triassic but disappear from the
fossil record at the T–J boundary, reappearing in the mid
Hettangian (~370 kyr coral gap).
We use atmospheric pCO2 reconstructions from the
literature in conjunction with these 4Arag limitations to
calculate the total dissolved inorganic carbon (TCO2) in the TJ ocean. Our results suggest that the T-J pCO2 increases
recorded by stomatal and pedogenic carbonate proxies would
depress saturation state to the point where it would be
extremely difficult for corals to biomineralise (4Arag < 2),
resulting in a coral and reef gap in the fossil record. However,
the Jurassic elevation of pCO2 observed in the proxies does
not produce complete carbonate undersaturation in the surface
ocean. Models suggest that higher pCO2 values (between 3000
ppm and 7000 ppm) could be possible, and at these levels, the
saturation state would have been low enough for aragonite
undersaturation in the surface ocean. This short but extreme
acidification in an ocean with low TCO2 would explain the
significant extinction of calcareous organisms and the Early
Hettangian coral gap.
Mineralogical Magazine
1415
Surface #11B-pH reconstructions and
insights into the dynamics of the
oceanic carbonate system during the
last deglaciation
M.A. MARTÍNEZ-BOTÍ1*, G.L. FOSTER1 AND D. VANCE2
School of Ocean and Earth Science, National Oceanography
Centre Southampton, University of Southampton,
Southampton SO14 3ZH, UK
(*correspondence: [email protected])
2
Bristol Isotope Group, Department of Earth Sciences,
University of Bristol, Bristol SO8 1RJ, UK
1
There is a long-standing debate about the role of an
isolated deep-ocean carbon-rich reservoir in the rise of
atmospheric CO2 during the last deglaciation. One of the most
commonly invoked hypotheses implies that CO2 is ‘stored’ in
the deep ocean during glacial periods, and that recommunication of this reservoir with the surface ocean and
atmosphere at deglaciations (mainly via upwelling in the
Southern Ocean) increases atmospheric pCO2. While several
studies in the Southern Ocean, Eastern Equatorial Pacific and
Indian Ocean have confirmed the validity of this hypothesis,
others have cast doubt on the existence and even the feasibility
of such 14C-depleted reservoir [1-5].
Boron isotopes in planktic foraminifera are a proven proxy
for surface oceanic pH [6, 7], which has been shown to
provide valuable insights into past changes in the ocean
carbonate system and ultimately into past atmospheric pCO2.
Here we will present novel results from sediment cores
retrieved from the equatorial regions of several ocean basins
that provide valuable insights into the causes and mechanisms
of deglacial pCO2 rise.
[1] Marchitto, Lehman, Ortiz, Fluckiger & van Geen (2007)
Science 316, 1456–1459. [2] Anderson, Ali, Bradtmiller,
Nielsen, Fleisher, Anderson & Burckle (2009) Science 323,
1443–1448. [3] Bryan, Marchitto & Lehman (2010) Earth
Planet. Sci. Lett. 298, 244–254. [4] Rose, Sikes, Guilderson,
Shane, Hill, Zahn & Spero (2010) Nature 466, 1093–1097.
[5] Hain, Sigman & Haug (2011) Geophys. Res. Lett. 38,
L04604. [6] Sanyal, Bijma, Spero & Lea (2001)
Paleoceanography 16, 515–519. [7] Foster (2008) Earth
Planet. Sci. Lett. 271, 254–266.
www.minersoc.org
1416
Goldschmidt Conference Abstracts
Preliminary estimation of scavenging
rates in the Guadalete estuary (Bay of
Cádiz, Spain) based on U-Th
disequilibrium series
C. MARTÍNEZ-RAMOS1, E. CUESTA2,
M. CASAS-RUIZ1, J.P. BOLÍVAR2, E.G. SAN MIGUEL2,
L. BARBERO3, AND M. BASKARAN4
Departamento de Física Aplicada, Universidad de Cádiz
([email protected])
2
Departamento de Física Aplicada, Universidad de Huelva,
Spain ([email protected])
3
Departamento de Ciencias de la Tierra, Universidad de Cádiz,
Spain
4
Department of Geology, Wayne State University, Detroit,
USA
1
Several samples were taken along salinity gradient in the
Guadalete River estuary (SW Spain), with the aim of
estimating the scavenging rates and residence times of U and
Th. Scavenging processes can be quantified from the
measurements of members of the U-Th series, such as 234Th
and 238U, based on the differences in the geochemical
behaviour with respect to sorption on to particulate matter. We
analyzed the dissolved and particulate 234Th in a suite of water
samples. Our results show that the dissolved U is conserved in
the estuarine mixing zone. Using a simple box model for the
particulate and dissolved 234Th, the calculated scavenging rate
constant k and the residence time 5 in the lower salinity
samples are 0.96±0.28 d-1 and 1.01±0.28 d, respectively. At
intermediate salinity, these values are 0.74±0.11 d-1 and
1.30±0.11 d, respectively. Scavenging rates and residence
times from samples in the surrounding Bay of Cádiz, are
0.56±0.08 d-1 and 1.69±0.08 d, respectively. A comparison of
these values indicate that there is active scavenging (lower
residence time) at low salinity region compared to high
salinity region towards the sea. Furthermore, these results
imply high scavenging rates in the Guadalete River estuary as
well as short residence times, as is normally the case in
estuarine areas.
Mineralogical Magazine
Biogeochemistry of Devonian shale
gas resources of the Midwest USA:
Antrim and New Albany Shales
A.M. MARTINI1, S.T. PETSCH2*, J.C. MCINTOSH3,
M. SCHLEGEL3, J. DAMASHEK4, S.E. MILLER5
6
AND M. KIRK
Dept. of Geology, Amherst College, Amherst, MA 01002
([email protected])
2
Dept. of Geosciences, University of Massachusetts Amherst,
Amherst, MA 01003
(*correspondence: [email protected])
3
Dept. of Hydrology and Water Resources, University of
Arizona, Tucson, AZ 85721
4
Dept. of Environmental Earth System Science, Stanford
University, Stanford, CA 94305
5
Dept. of Geophysical Sciences, University of Chicago,
Chicago, IL 60637
6
Sandia National Laboratory, Albuquerque, NM 87185
1
To better understand the role of subsurface microbial
communities in natural gas generation in shales, we have
pursued comparison of the aqueous geochemistry, gas isotope
geochemistry, organic geochemistry, and microbial ecology in
two US gas shale formations. Both formations exhibit key
geochemical/isotopic indicators of methanogenesis, including
high concentrations of HCO3-; "13C values of HCO3- between
10-33 "; low concentrations of SO42- and CH3COO-; and a
strong co-variance of H2O and CH4 "D values. These
indicators reach more extreme values in the Antrim compared
to the New Albany, suggesting greater overall microbial gas
generation and/or a more active microbial community in the
Antrim. Analysis of extractable hydrocarbons from shale core
samples also reveal that biodegradation is much less severe in
the New Albany compared to the Antrim. 16S rRNA partial
gene sequences from production waters of both formations
include both Archaea and Bacteria. Phylogenetic analyses
suggest different microbial communities occur both between
and within the two formations, yet all exhibit broadly similar
functions of bacterial fermentation of hydrocarbons
accompanied
by
predominantly
hydrogenotrophic
methanogenesis.
www.minersoc.org
Goldschmidt Conference Abstracts
Assessment of trace element
concentration related to the K-Pg
event by the use of PXRF
Zircon typologies and internal
structures as petrogenetic indicators
in contrasting Variscan biotite-rich
granite plutons from Northern
Portugal
FRANCISCO J. MARTÍN-PEINADO1*
2
AND FRANCISCO J. RODRÍGUEZ-TOVAR
Department of Soil Science, University of Granada, Spain
(*correspondence: [email protected])
2
Department of Stratigraphy and Paleontology, University of
Granada, Spain
1
The field portable X-ray fluorescence (PXRF) analyser is
a useful tool for screening and assessing contaminated areas.
This equipment allows in situ trace-element concentrations to
be determined both rapidly and easily. According to its
advantages, the method reveals especially appropriate when
sampling is difficult or even forbidden (e.g. scarce sample,
difficult access to sampling or protected areas), as is the case
of the K-Pg boundary layer in some sections. To check its
potential applicability, the K-Pg boundary layer at the
Caravaca section (Murcia province, SE Spain), has been
analyzed. In this section, the 2-3 mm thick K-Pg rust-red
boundary layer has been previously characterized by the
presence of Ir and other geochemical anomalies that, together
with other evidences, where related to a extraterrestrial origin.
Samples were taken to analyse in situ the element
concentrations in the sediments of the K-Pg boundary interval,
from the uppermost Maastrichtian to the lowermost Danian,
including the boundary layer, as well as in the infilling
material of trace fossils registered at the K-Pg boundary
interval. The results indicated statistical significant differences
between the different samples analysed for the following
elements: Zn, As, Ti, Fe, Sr, Ca and K. Maximum values of
these elements (up to 1480 ppm of As, 1272 ppm of Zn and
166 g/kg of Fe) were detected in the K-Pg boundary layer.
Cretaceous sediments were characterized by the lowest
concentration of these elements but the maximum values of
calcium. Tertiary materials statistically differ from the
Cretaceous sediments, with significant increase in Sr, Fe, and
Ti and strong decrease in Ca content. Finally, trace fossils
registered at the K-Pg boundary interval show variable
concentrations according to the type of infilling material.
In this study, PXRF has proved to be a useful tool for
screening and assessing particular fossil examples as that from
the K-Pg boundary for quick and easy in situ determination of
trace-element concentrations related to this type of events.
Mineralogical Magazine
1417
H.C.B. MARTINS1 AND P.P. SIMÕES2
Centro de Geologia, Faculdade de Ciências, Universidade do
Porto, Rua do Campo Alegre, 4169-007 ([email protected])
2
Centro de Geologia da Universidade do Porto/ Universidade
do Minho, Campus de Gualtar ([email protected])
1
The aim of the present morphological zircon study is to
characterize the sources reservoirs involved in the generation
of the different type of granites, testing the classic ‘Pupin
method’ and zircon geochemistry against the petrogenetic
indications given by geochemical and isotopic data. In
northern Portugal large volumes of granitoids were emplaced
during the last stage (D3) of the Variscan orogeny and display
a wide range of petrological signatures. We studied the
morphologies, internal structures and geochemistry of zircons
from (1) Syn-D3 biotite granitoids: Ucanha–Vilar, Lamego,
Felgueiras, Sameiro and Refoios do Lima plutons (2) Late- D3
biotite-dominant granitoids: Vieira do Minho pluton and (3)
post- D3 biotite granitoids: Vila Pouca de Aguiar pluton. The
typological evolutionary trends suggest a crustal or
dominantly crustal origin for the syn-D3 Refois do Lima
granite and for the late- D3 pluton whereas an hibridisation
process is proposed for the Ucanha-Vilar, Lamego and
Sameiro granites. The zircon population from the post- D3
granites define a typological evolutionary trend betweeen calcalkaline and subalkaline granites suggesting a under crustal or
mantle source. The petrogenetic model proposed by zircon
typological and geochemical study in all plutons is in
accordance with geochemical and isotopic data. In fact the
Syn-D3 biotite granitoids display Sri ratios and 0Nd values
varying in the range 0.7072-0.7116 and - 4.4 to - 6.3,
respectively; the late- D3 pluton present Sri= 0.7089-0.7090
and 0Nd = # 5.6 to - 5.7 and finally post- D3 biotite granitoids
present weakly evolved isotopic compositions, Sri=0.7044–
0.7077 and 0Nd=12.0 to 12.6.
www.minersoc.org
Goldschmidt Conference Abstracts
1418
Radon risk and their geological
controle in the region of Amarante
(Northern Portugal)
L. MARTINS , M.E.P. GOMES , L. NEVES
2
AND A. PEREIRA
1
1
2
Dep. of Geology, UTAD, 5001-801 Vila Real, Centro de
Geociências, Portugal
2
IMAR, Dep. of Earth Sciences, 3000-272 Coimbra, Portugal
1
Amarante is located in the border of an extensive tarditectonic massif, formed by Hercynian granites. Around
Amarante city, two types of the granitic rocks occur: AT1 is a
coarse-grained, porphyritic, bi>mu (biotite>muscovite) and
AT2 is granite with medium-grained, bi>mu, porphyritic.
Other units are metamorphic rocks of Silurian and Devonian
in Aboim village. Representative samples of granitic rocks
unaltered and with different degrees of alteration were studied.
The variations of SiO2, TiO2, Fe2O3t, MgO, V, Zr, Sr, Ba, U,
Fe/(Fe+Mg), their subparallel REE of two unaltered granites
suggest a relation by crystal fractionation; and AT2 is the most
differentiated granite. The average uranium content of the
AT2 granite was found to be 18 ppm, higher than the crustal
average, subsequently showing a high radon potential.
Accessory minerals from granites were studied through SEM
suggesting that, U and Th are mainly concentrated in zircon,
monazite, uraninite, thorite and thorianite. In three geological
units was evaluated a radioactive background with gamma-ray
portable spectrometers and in the granitic rock a gamma ray
flux of 289 6Gy/h measured in direct contact with the rock
was observed; a lower flux of 155 6Gy/h was observed for
metamorphic rocks that also outcrop in the area. An important
measured system of fractures with tardi-hercynian directions
affects the studied area. Some fractures that crosscut the
Amarante granite show a moderate degree of uranium
enrichment (26 ppm), with gamma ray fluxes up to 420
6Gy/h.
The indoor radon concentrations, during the winter, were
measured in 73 dwellings with CR39 passive detectors. The
highest radon levels occur in 35 dwellings and built over the
granite AT2 (geometric mean of 430 Bq/m3), which also
shows the highest uranium. Buildings from Aboim village
show the lowest U contents and consequent lowest radon
levels. Fourteen representative samples of groundwater were
analysed for Rn, gross + and 7. Groundwater related with AT2
has the highest radon (up to 2295 Bq/l) and the highest gross +
(up to 0, 83 Bq/l) allowed by Portuguese legislation. Overall,
we can conclude that the area of Amarante city presents a
moderate to high radon risk and the area of Aboim presents
low to moderate radon risk.
Mineralogical Magazine
Nitrogen fixation through early Earth
history
F. JAVIER MARTIN-TORRES*
ALFONSO DELGADO-BONAL
AND
Centro de Astrobiologia (CSIC-INTA), Carretera de Ajalvir,
km.4, 28850, Torrejón de Ardoz, Madrid, Spain
(*correspondence: [email protected])
Nitrogen is an essential part of many of the chemical
compounds, such as proteins and nucleic acids, which are the
basis of all life forms. However, N2 cannot be used directly by
biological systems to build the chemicals required for growth
and reproduction. Before its incorporation into a living
system, N2 must first be combined with hydrogen. This
process of reduction of N2, commonly referred to as nitrogen
fixation may be accomplished chemically or biologically. In
this paper we present a study of the evolution of nitrogen
fixation through Earth history between 3.4 and 0.5 Gyr ago
and its effects on the geophysical Earth system.
www.minersoc.org
Goldschmidt Conference Abstracts
Metal-rich brown layers in Arctic
Ocean sediments: Climate versus
diagenesis
C. MÄRZ1*,2, A. STRATMANN2, S. ECKERT2,
B. SCHNETGER2, S.W. POULTON1 AND H.-J. BRUMSACK2
CEGS, Newcastle University, NE1 7RU Newcastle upon
Tyne, UK (*correspondence: [email protected])
2
ICBM, Universität Oldenburg, 26111 Oldenburg, Germany
1
The sediments of the central Arctic Ocean are a unique
archive for past climate and environmental changes in this
highly sensitive ocean region. Amongst the most prominent
and widespread features of Arctic Quaternary deposits are
marked cm- to dm-thick brown layers. Their origin is unclear,
and might either be related to specific environmental
conditions during either deposition, or to diagenesis. To
understand the genesis and composition of these layers, we
studied sediments cores from the southern Mendeleev Ridge
(RV Polarstern Expedition ARK-XXIII/3) by inorganicgeochemical methods (XRF, ICP-MS, Fe extraction) at high
resolution.
The brown layers are consistently enriched in Mn and Fe
(oxyhydr)oxides, but also in various trace metals (As, Co, Cu,
Mo, Ni) that most probably adsorbed to Mn and Fe phases and
were scavenged from the water column. These metal
enrichments are likely related to enhanced riverine input to the
Arctic Ocean, as Arctic river waters are known to be metalrich. Increased fluvial runoff should be related to a more
intense hydrological cycle under warmer (interglacial-type)
climate conditions.
However, pore water data indicate ongoing Mn (but not
Fe) diagenesis in the recovered sediments, questioning the
primary nature of the observed metal enrichments. We suggest
that relative changes in the enrichment patterns of specific
trace metals (especially of Co and Mo) in individual brown
layers might be used to determine if the composition of the
respective layers was overprinted by diagenetic processes.
In detail, we observe that brown layers currently serving
as pore water Mn sources have Co/Mo ratios above 5, while
those layers acting as pore water Mn sinks have Co/Mo ratios
below 5. This trace metal pattern may be explained by
preferential retention of Co in dissolving Mn (oxyhydr)oxide
layers. In contrast, Mo is preferentially desorbed, diffuses
through the pore space in conjunction with Mn, and re-adsorbs
onto freshly precipitating, authigenic Mn (oxyhydr)oxides.
However, the wider application of trace metal ratios as
‘diagenetic markers’ in Arctic sediments requires further
investigation.
Mineralogical Magazine
1419
Nitrate reduction drives distant
sulfide oxidation
U. MARZOCCHI1*, N. RISGAARD-PETERSEN2,
N.P. REVSBECH1 AND L.P. NIELSEN1
Section for Microbiology, Department of Biological Sciences,
Aarhus University, 8000 Aarhus C, Denmark
(*correspondence: [email protected])
([email protected])
([email protected])
2
Center for Geomicrobiology, Aarhus University, 8000 Aarhus
C, Denmark
([email protected])
1
Recent observations in marine sediments show that
electric currents may couple oxygen reduction at the
sediments surface to sulfide oxidation deep within the
sediment [1]. In this study we tested if electric currents can
couple also nitrate reduction to sulfide oxidation
Sediment collected from Aarhus bay (Denmark) was preincubated for 2 months in two different aquaria: one with oxic
seawater and another where oxygen was replaced with nitrate.
After the pre-incubation, sulfide, oxygen and pH distribution
in the sediment were determined with microsensors whilst a
biomicrosensor was used to measure nitrate & nitrite.
Our concentration profiles showed a 4 mm separation
between nitrate and sulfide in sediments incubated with nitrate
in the water column. In sediments incubated with oxygen in
the water column, oxygen and sulfide were separated by 25
mm. In both types of incubation, the pH signature indicated
the presence of electric currents coupling spatially segregated
biogeochemical processes.
These results provide an important indication of the
capacity of nitrate to sustain sulfide depletion over distances
not coverable by diffusion only. Moreover demonstrating that
oxygen is not the only electron acceptor able to sustain such a
system, implies that this distant coupling can be more spread
in nature than previously expected.
[1] Nielsen et al. (2010) Nature 463, 1071-1074.
www.minersoc.org
1420
Goldschmidt Conference Abstracts
Origin of Cameroon Line basanites
from metasomatized lithosphere
A. MARZOLI1*, F.T AKA2, M. CHIARADIA3,
L. REISBERG4 AND R. MERLE1
University of Padua, Italy ([email protected])
(*correspondence: [email protected])
2
IRGM-ARGV, Ekona, Cameroon ([email protected])
3
Université de Genève, Switzerland
([email protected])
4
CRPG (CNRS UPR2300), Université de Lorraine, France
([email protected])
1
The Cameroon Line is located above a zone where a sharp
gradient in lithospheric thickness occurs north of the Congo
Craton keel [1]. This zone was the site of magmatic activity
since (at least) the beginning of the Cenozoic until the Present.
Here we investigate the Miocene basic-ultrabasic magmatism
of Mt. Bambouto volcano (Western Cameroon). Its 20 to 15
Ma old basanitic flows and alkali-basaltic dykes are
characterized by extreme enrichments in Sr (up to 2200 ppm),
Ba, and P and by generally high TiO2 (up to 4.6 wt%). The
other alkali basaltic flows from Mt. Bambouto lack such
extreme compositions and resemble other typical continetal
and oceanic Cameroon Line basalts. Compared to the alkali
basaltic flows, the Mt. Bambouto basanites yield also slightly
higher initial 87Sr/86Sr (0.7034-0.7036 vs 0.7030-0.7033) and
143
Nd/144Nd (0.51290-0.51285 vs 0.51285-0.51283) and lower
206
Pb/204Pb (19.4-19.6 vs 19.6-19.9). Moreover, basanites are
characterized by higher initial 187Os/188Os (0.191-0.220) than
the only analyzed alkali basalt (187Os/188Os = 0.127). The high
Os isotopic compositions of basanites would seem to suggest a
significant amount of crustal assimilation (ca. 25 or 35% of
silicic upper or mafic lower crust, respectively). However such
an interpretation is not easy to reconcile with their OIB-like
Sr-Nd-Pb isotopic compositions, their little evolved wholerock compositions (e.g. MgO 9-11 wt%, Cr 350-550 ppm) and
their mineralogy (high-Mg olivines: Fo80-88, high pressure
clinopyroxenes: crystallized at ca. 10 kbar [2]). Alternatvely,
we suggest that basanites derived from mafic material
entrapped within the mantle, which would also be compatible
with their major and trace element compositions. In particular,
we propose that these mafic veins may have metasomatically
pervaded the continental lithosphere during the early stages of
Cameroon Line magmatism and developed relatively high
187
Os/188Os prior to the Mt. Bambouto volcanism.
Magnetic anisotropy of artificial
deposits
A.V. MASHUKOV*, A.E. MASHUKOVA
AND S.A. SIMINCHUK
Siberian Federal Univ., Krashoyarskiy Rabochiy, 95,
Krasnoyarsk, 660025, Russia
(*correspondence: [email protected])
There was studied the influence of the sizes of grains of
Fe3O4 in the artificial deposits, precipitating in the Earth
magnetic field, on magnetic characteristics of the samples. To
obtain most of the information, for the same samples, there
was used a complex of investigations of research of same
samples was used for obtaining more information.
The dependences of uniaxial anisotropy constant (%),
maximum losses from the rotator hysteresis (Wm), the value of
the alternating magnetic field, half reducing residual
magnetization (
) on grain size, are shown in table 1.
Grain size
Fe3O4, mcm
K,
Joule
/m3
Wm ,
Joule
/m3
0<d88
410,0
1020,0
Oe
320,0
Intensi
ty
1,9
8 < d 8 16
305,0
820,0
280,0
1,8
16 < d 8 32
180,0
500,0
200,0
1,5
32 < d 8 44
130,0
410,0
120,0
1,3
44 < d 8 64
115,0
225,0
110,0
1,2
64 < d 8 100
105,0
160,0
105,0
1,1
100 < d 8 150
105,0
160,0
100,0
1,1
Table 1: Dependences of magnetic characteristics on grain
size
The X-ray technique of straight pole figures (intensity in
table 1) shows anisotropic distribution of axes for particles d >
40 mcm.
Thus, the magnetic characteristics of rocks are controlled
by ferrimagnetic particle size as well as its crystallographic
ordering.
[1] Reusch et al. (2010) G-3 11, Q10W07. [2] Putirka (2008)
Rev. Mineral. Geochem. 69, 61–120.
Mineralogical Magazine
,
www.minersoc.org
Goldschmidt Conference Abstracts
Geochemical variation of fracture
carbonates in crystalline bedrock
O. MASKENSKAYA*, H. DRAKE, P. PELTOLA
AND M. ÅSTRÖM
Geochemistry research group, School of Natural Science,
Linnaeus University, SE Sweden
(*correspondence: [email protected])
The current study is focused on trace and rare earth
elements (REE) in carbonates from two fracture mineral
generations formed at separate events at very different
conditions, but in the same granitoid fracture system. Both
generations are well-characterized and separation is based on
paragenesis, &13C, &18O, 87Sr/86Sr and crystal habit [1]. The
oldest generation was formed in the Proterozoic era (~1.4 Ga)
[2] and the youngest in the Paleozoic era (~440-400 Ma) [2,
3].
In total, 41 calcite samples and 1 dolomite sample from 17
drill cores (up to 1 km depth), originating from the Swedish
Nuclear Fuel and Waste Management Co’s investigations in
the Laxemar-Simpevarp area, SE Sweden, were analysed
(with ICP-MS of calcite leachates).
Figure 1: NASC-normalized REE patterns (REEn) of
Proterozoic carbonates (left) and Paleozoic carbonates (right),
NASC according to [4].
Proterozoic carbonate shows two groups (a and b) which
differ both in REEn patterns and trace element compositions,
accordingly: a) positive Eun- and Lan-anomalies, very low
light REE concentrations, gradually enriched in REEn from
Gdn to Lun, relatively high amounts of Sr, Mg and Fe; b) no
Eun- or Lan-anomalies, gradual decrease in REEn from Lan to
Lun, depleted in other trace elements.
Paleozoic calcite shows larger REEn variation including
e.g. both slightly enriched heavy or middle REEn, as well as
gradual depletion from Lan to Lun. All Paleozoic calcite
samples show low trace element concentrations and large Mn
and Y variations. Observed trace element variations in
different generations are predominantly caused by factors that
influenced composition of parental solutions. Intense
hydrothermal wall rock alteration in the Proterozoic, and
microbial activity and descending organic-rich fluids in the
Paleozoic might be these factors.
[1] Drake & Tullborg (2009) Appl. Geochemistry 23, 715-732.
[2] Drake et al. (2009) Lithos 110, 37-49. [3] Alm et al.
(2005) Report SKB-R-05-66. www.skb.se. [4] Haskin et al.
(1968) Pergamon vol.1, 889-911.
Mineralogical Magazine
1421
Microbial sulfur isotope fractionation
in littoral sediments: Interpreting
" 34S variability in Archean rocks
PAUL R.D. MASON1, MARJOLIJN C. STAM1,
ANNIET M. LAVERMAN2, CELINE PALLUD3
1,4
AND PHILIPPE VAN CAPPELLEN
Utrecht University, The Netherlands ([email protected])
Universite Pierre et Marie Curie, Paris, France
3
UC Berkeley, Ca, USA
4
Georgia Institute of Technology, Atlanta, Ga, USA
1
2
Sulfur isotope variations in Archean rocks have been used
to argue for the presence of sulfate reducing mircoorganisms
as one of the earliest forms of life in the early Archean, back
to 3.49 Ga [1-3]. Extensive laboratory pure culture and
incubation studies with modern sediments have been used to
support these interpretations with measured and predicted "34S
values up to 49 ‰ for a single reduction step of sulfate to
sulfide (e.g. [4, 5]). Here we expand the available data for
isotope fractionation by natural communities of
microorganisms, with an extensive laboratory flow through
reactor study, that enables sulfate reduction under close to in
situ conditions. Sediments were collected from a brackish
marine estuary (Sheldt estuary, The Netherlands), a
hypersaline soda lake (Mono Lake, California), a freshwater
river (Scheldt, Belgium) and a shallow marine hydrothermal
system (Vulcano, Italy).
Sulfate reduction rates (SRR) varied between 5 and 180
nmol cm-3 h-1 with corresponding isotope fractionations (!),
calculated as the difference between inflow sulfate and
product sulfide, of 5 to 43 ‰. No overall relationship was
found between SRR and ! , but weak correlations were found
within the individual sites. Isotope fractionation data fall
within the range predicted by standard models with lowest
values at highest rates, but do not fall towards the smallest
values predicted by the Rees model [5]. Our data indicate that
relatively small isotope fractionations (<20 ‰) would be
typical for sulfate reducing communities, under optimum
growth conditions, and in the absence of competition from
other metabolisms. Without an oxidative component in the
sulfur cycle, widespread microbial sulfate reduction would
result in minor "34S variations and may be more widespread in
the Archean than previously envisaged.
[1] Shen et al. (2001) Nature 410, 77–81. [2] Ueno et al.
(2008) GCA 72, 5675–5691. [3] Shen et al. (2009) EPSL 279,
383–391. [4] Detmers et al. (2001) Appl. Env. Microbiol 67,
888–894. [5] Rees (1973) GCA 37, 1141–1162.
www.minersoc.org
1422
Goldschmidt Conference Abstracts
Catching a collapsing solidification
front through thermal gradient
experiments
Promoting As release by aerobic
water infiltration into Holocene
aquifer, Bangladesh
M. MASOTTA1*, C. FREDA2 AND M. GAETA1,2
Sapienza - Università di Roma, Italy
(*correspondence: [email protected])
2
Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
H. MASUDA1*, S. MAEDA1, K. OKABAYASHI1,
A.A. SEDDIQUE2, M. MITAMURA1,
N. MORIKAWA3 AND S. NAKAYA4
1
Large
explosive
eruptions
commonly
emplace
differentiated (i.e. rhyolite, phonolite), crystal-poor juveniles.
This is a well-known paradox in volcanology, considering that
magmatic differentiation implies crystallization and that
crystal-melt separation processes (e.g. crystal settling) are
more efficient in high-temperature, primitive magmas.
Conversely, differentiated, crystal-poor juveniles are usually
associated to shallow, thermally-zoned feeding systems. Here,
the generation of differentiated, crystal-poor magmas may be
explained throughout the development of a ‘solidification
front’ [1] at the roof of the chamber. Although natural
evidences and theoretical models support the solidification
front concept, its capability to originate differentiated, crystalpoor magmas remains unconstrained.
By experimentally investigating the formation of a
solidification front in a thermally zoned environment we
demonstrate its capability to originate glassy belts and pockets
phonolitic in composition (figure 1). We recognize in the
instability and collapse of rigid crystal frame the driving
mechanism producing segregation and upward accumulation
of crystal-poor melts and suggest this model may apply to
thermally zoned magma chambers.
Dep. Geosciences, Osaka City Univ., Osaka 558-8585, Japan
(*correspondence: [email protected])
([email protected], [email protected],
[email protected])
2
Jessore Sci. Tech. Univ., Jessore-7407, Bangladesh
([email protected])
3
GSJ, AIST, Tsukuba, 305-8563, Japan
([email protected])
4
Dep. Eng., Shinshu Univ., Nagano 380-8553, Japan
([email protected])
1
In order to investigate the timing of As release in the
Holocene groundwater aquifer, Sonargaon, Bangradesh, age of
groundwaters were determined using 3He/4He ratio. Among
the ten well waters collected from the active recharging zone
of the Holocene aquifer within 300 m diameters, the lowest
3
He/4He ratio was found in the groundwater containing highest
concentration of As >1000 µg/L. Groundwater giving the
highest 3He/4He ratio contained <1µg/L As. Compared with
the histrical tritium unit in the air of New Delhi, the former
groundwater was recharged after 1980, while, the latter was
before 1970. As concentration of the groundwater increases
decreasing 3He/4He ratio, indicating that the As release started
after 1980.
In this area, the As conmtaninated Holocene aquifer
directly contacts to As-free Pleistocene aquifer due to lack of
the Pleistocene impermeable clay layer. Presumably, the As
release is triggered by increasing infiltration of groundwater
into the Holocene aquifer in association with the increasing
withdrawel of groundwaters from the Pleistocene aquifer to
cause drastic change of the Holocene aquifer condition.
Fe rich chlorite was found to be a primary source of As,
and this mineral was oxidized to precipitate goethite in the
aquifer. Thus, the rapid infiltration of aerobic water into the
Holocene reducing aquifer is the trigger to cause oxidationdecomposition of the As-bearing chlorite.
Figure 1: Solidification front obtained in a thermal gradient
experiment performed at 300 MPa and T ranging 1000-850°C.
The glassy belt (top, cooler zone of the capsule) is phonolitic
in composition.
[1] Marsh (2002) Geochim. Cosmochim. Acta 66, 2211–2229.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Experimental study on As and Cd
releases from anoxic sedimentary
rock under anoxic and aerobic
conditions
The Mesozoic evolution of the West
Iberian Margin as witnessed by
magma geochemistry
J. MATA1, C.F. ALVES1, R. MIRANDA1,2, L. MARTINS1,
J. MADEIRA2, P. TERRINHA2, N. YOUBI1,3,
M.K. BENSALAH1,3 AND M.R. AZEVEDO4
S. MASUDA, Y. OGAWA*, K. SUTO AND C. INOUE
Graduate School of Environmental Studies, Tohoku
University, Miyagi 980-8579, Japan
(*correspondence: [email protected])
The dissolution behaviors of As and Cd from the anoxic
sedimentary rock and subsequent immobilization mechanism
were investigated under anoxic and aerobic conditions.
Under aerobic condition, the decrease in pH and
concomitant Cd release were attributable to oxidative
dissolution of sulfide minerals, and 22 % of Cd in rock sample
was dissolved out for 2 months. On the contrary, Cd
concentration in the solution reacted under anoxic condition
was maintained low level, and the contribution of dissolved
Cd was only 0.14 %.
Arsenic was released as arsenite under both conditions.
The As concentrations in extracts under both conditions was
small, and the maximum contributions of As dissolution were
about 1 %. The XANES spectra reveal that samples before the
extraction contained the sulfide form As and As(V). Under
aerobic condition, the As sulfide completely decomposed
within a month and only As(V) existed in the samples after
extraction.
The chemical state of As in samples oxidized under 100%
humidity was changed to sulphide form to oxide and/or
strongly sorbed ones. This experiment shows the change in
chemical states of As within rock sample before the contact
with water, and the result reveals that the oxidation of As
sulfide did not lead to large amounts of As release. On the
contrary, under anoxic condition, As and Cd concentrations
were maintained low and the sulfate-rich acidic solution was
not produced. Furthermore, the sulfide As were still remained
in samples extracted for 2 months. These results indicate that
the sulfide minerals containing As and Cd in anoxic
sedimentary rock almost remained during extraction
experiment for 2 months.
Mineralogical Magazine
1423
Centro de Geologia da Univ.Lisboa ([email protected])
Lattex/IDL
3
Université Cadi Ayyad Marrakech, Morocco
4
GeoBioTec, University of Aveiro
1
2
The main phases of the onshore West Iberian Margin
(WIM) Mesozoic evolution were marked by the occurrence of
3 magmatic cycles separated by time lags of (50 Ma. The first
cycle (202 - 198Ma) is linked to the initial stages of the
Central Atlantic opening, being considered part of an
important LIP: the Central Atlantic Magmatic Province.
Magmatism produced low-Ti tholeiites characterized by
(La/Yb)n < 4, (87Sr/86Sr)0 > 0.7050 and (143Nd/144Nd)0 down to
0.512268 which post-date the beginning of syn-rift
sedimentation by ( 20-30 Ma. The second cycle (147 141Ma) was coeval of the westward rift axis migration from
the Lusitanian Basin to the location where oceanization was
successfully reached. Preserved rocks are hypabyssal with
transitional affinities (moderately alkaline to subalkaline), 6 <
(La/Yb)n < 12, (87Sr/86Sr)0 = 0.70403 to 0.70456 and
(143Nd/144Nd)0 = 0.512531 to 0.512664. The third cycle (94 to
72 Ma) was synchronous with the opening of the Bay of
Biscay and of the rotation of the Iberia. It was characterized
by the formation of abundant alkaline magmatism presenting
(La/Yb)n up to 21, (87Sr/86Sr)0 down to 0.702870 and
(143Nd/144Nd)0 up to 0.512897. The geochemical evolution
depicted by WIM magmas expresses the diminishing role of
lithospheric sources. They prevailed during the first cycle,
when magmas present fingerprints of supra-subduction
processes probably developed in the lithosphere during the
Upper Paleozoic Variscan orogeny.
www.minersoc.org
1424
Goldschmidt Conference Abstracts
Molybdate sorption from steel slag
eluates by soils
Brackish marine water intrusion in
deep fractured granitic bedrock
K. MATERN1*, T. MANSFELDT.1 AND T. RENNERT2
Department of Geosciences, Soil Geography/Soil Science,
University of Cologne, Albertus-Magnus-Platz, 50923
Cologne, Germany
(*correspondence: [email protected])
2
Institute of Earth Sciences, Friedrich Schiller University of
Jena, Burgweg 11, 07749 Jena, Germany
([email protected])
F.A. MATHURIN1*, B.E. KALINOWSKI2, M. ÅSTRÖM1
3
AND M._LAAKSOHARJU
1
Steel slags are an industrial by-product. The latest statistic
of 2009 show a use which amounted to 4.62 mio. t slag in
Germany [1]. Over 60 % have been used as construction
material (ways, roads, earthworks). Molybdenum is added
during steel processing in order to harden the steel. The
objective of this study was to evaluate the sorption behavior of
molybdate from slag eluates towards different soils to assess
the risk that may arise from contamination of ground water by
leaching of molybdate.
Molybdate sorption batch experiments were carried out
with eluates obtained from (i) steel slag (Linz-Donawitz
operation, LD) and (ii) electric furnace slag (EF).
Six different soils and sediments were chosen to provide a
wide range of chemical properties (pH 4.0 to 7.6; dithionitextractable Fe 0.73 to 14.69 mg kg-1). Molybdate sorption
experiments were carried out at pH of the steel slag eluates
(pH 11 to 12) as well as at pH adjusted to soil pH. The data
were evaluated with the Freundlich equation.
Molybdate sorption exhibited a maximum near pH 4 for
steel slag eluates which were adjusted to soil pH and
decreased rapidly with increasing pH until sorption was
virtually zero at pH > 11. Sorption was greater for soils with
high amounts of dithionite-extractable iron oxides. Molybdate
sorption behavior of both eluates was similar. After reaching
equilibrium, the pH of the EF steel slag eluate was lower than
the pH of the LD steel slag eluate that was caused by different
buffer capacities. Some soils were able to decrease the pH of
the EF steel slag eluates by about four pH units enhancing the
sorption of molybdate.
The Mo-sorption behavior from steel slag eluates is
similar to sorption experiments with commercial Mo standard
solutions. The same factors affect Mo-sorption, but Mosorption from steel slag eluates is more complex as a result of
eluate chemistry.
[1] Merkel (2010) Report des FEhS-Institutes 1, 14.
Mineralogical Magazine
Department of Natural Sciences, Linnaeus Univ., Kalmar,
Sweden (*correspondence: [email protected])
2
Swedish Nuclear Fuel and Waste Management Co,
Stockholm, Sweden
3
Geopoint AB, Stockholm, Sweden
1
Groundwater residing in the fractures of granitic bedrock
in a costal environment can be related to the climate changes
and seawater stages. The purpose of this study is to
hydrogeochemically characterise the different brackish marine
water types present at the Äspö Hard Rock Laboratory, an
underground bedrock laboratory situated at the Baltic Sea
shore, in south-east Sweden [1].
Groundwater samples collected from the different
boreholes along the tunnel at 50-560m depth were classified
according to their Cl content and &18O signature. Groundwater
classified as brackish marine component was used to study the
Mg/Cl and Mg/K ratios in detail.
For samples with Mg/Cl ratio higher than 0.03, two
different trends can be observed both with respect to the Mg
and the Cl concentrations. One group of samples is distributed
along an evolution line from the present Baltic Sea water (Cl =
3380 mg.L-1). The other group, consisting of fewer samples
and higher Cl concentration, appears to gather along an
evolution line from the ancient Baltic Sea, also called the
Littorina Sea (Cl = 6500mg.L-1; [2]). However, the samples of
the second group have lower Mg and Cl concentration than the
original Littorina Sea composition. The brackish marine water
considered to be influenced by Littorina Sea water is located
in relatively shallow fracture sections at 30-180m depth. This
suggests storage of Littorina Sea water as pockets in some
fractures. Nevertheless the high Mg/K ratio, which is more
than four times the ratio of the Littorina Sea water, indicates
that a strong water-rock interaction occurred since the
Littorina sea water intrusion. The alignment of the samples
along different evolution lines of the two different brackish
Sea water types shows that mixing processes with other water
types [3] take place in the fracture network.
[1] Laaksoharju et al. (1999) Appl. Geoch 14, 835–859.
[2] Sjöberg et al. (1984) Chem. Geol. 42, 147–158. [3] Smellie
et al. (1995) Jour Hydro 172, 147–169.
www.minersoc.org
Goldschmidt Conference Abstracts
Depth profile of 129I/127I ratio in
Andisol collected in preserved field of
NIAES, Tsukuba, Japan
H. MATSUZAKI1*, Y. MAEJIMA2, T. OHKURA2,
Y.S. TSUCHIYA1, K. ABE1, Y. MIYAIRI3
4
AND Y. MURAMATSU
The University of Tokyo, Tokyo 113-8656, Japan
(*correspondence: [email protected])
2
NIAES, Tsukuba 305-8604, Japan
3
AORI, The University of Tokyo, Chiba 277-8564, Japan
4
Gakushuin University, Tokyo 171-8588, Japan
1
Depth profile of 129I/127I ratio were measured as well as
iodine concentration, carbon concentration and 14C/12C in
Japanese Andisol collected in the well preserved field of
National Institute for Agro-Environmental Sciences, Tsukuba,
Japan. Today, most of 129I in the surface environment
involving soils is originated in the human nuclear activities:
atmospheric nuclear bomb testing, spent nuclear fuel
reprocessing, and nuclear acceident. To estimate total
deposition of 129I in soil precisely and to investigate iodine
transfer process correctly, the depth profile information is
essential. From the gradient of the profile iodine transfer
model can be constructed. If 14C/12C profile shows the signal
from the bomb testing (110 pMC just below the surface), the
sampling field has been undisturbed at least several decades
[1]. This study was the case.
Resulting 129I/127I depth profile shows steep decreasing
trend above 20cm depth. This part can be fitted simple
diffusion curve (error function). Below this depth 129I/127I
come to be rather constant. This observation suggests that
there are at least two component of iodine: quick diffusion
component (with which most of recent 129I is carried) and
rather static component (maybe as old as the mother material
of the soil).
The maximum 129I/127I ratio in Tsukuba (this study) is 1.67
x 10-8 at 1.5cm deep which is as twice as higher than the
Shimokita soil (7.29 x 10-9) [1]. This should be due to the
influence of a nuclear fuel reprocessing plant at Tokai area
located about 60km northern east of Tsukuba. Total deposition
density of 129I was calculated using 129I/127I ratio profile and
iodine concentration of each depth and soil density. That was
0.036 Bq/m2 corresponding to 2.6 x 1013 atoms/m2. These data
should be a reference for the evaluation of the influence of the
nuclear power plant acceident like the Fukushima dai-ichi
power plant.
Tracking permanent CO2 storage in
basaltic rocks using conservative and
reactive tracers at the CarbFix
injection site, Iceland
J.M. MATTER, M. STUTE AND W. BROECKER
LDEO, Palisades, NY 10964 ([email protected])
Injection of CO2 modifies ambient formation waters,
inducing fluid-rock reactions that may lead to mineral
carbonation of the CO2. In the CarbFix pilot CO2 injection
project in Iceland, we are investigating in situ mineral
carbonation of CO2 in a basaltic aquifer. At the moment, the
pilot test involves the injection of 2, 200 tons of CO2. The CO2
is injected dissolved in water at a rate of 0.07 kg/s of CO2 in 2
kg/s of water at 19°C [1].
The success of mineral carbonation in basaltic rocks
depends on the ability to monitor and understand the behavior
of the injected CO2. The currently existing monitoring
techniques in CO2 capture and storage are insufficient to
characterize mineral carbonation in any storage reservoir.
Most geophysical detection methods require that CO2 is
present as a supercritical phase. Dissolved CO2 and chemically
transformed carbon thus avoid detection.
We are using a multi tracer approach, including
conservative and reactive tracers to track CO2 storage in
basaltic rocks. Trifluormethylsulphur pentafluoride (SF5CF3),
a conservative tracer, is injected in pulses into the CO2 gas
stream at a concentration of 2700 pptv. It is used to
characterize the physical transport processes of advection and
dispersion of the CO2 solution. Furthermore, the injected CO2
is tagged with radiocarbon (14C). Radiocarbon is injected as
dissolved bicarbonate at a concentration of 1.20x101 Bq/kg of
injected water. This results in 5x enrichment compared to the
1850 background. The total 14C activity needed for the 2, 200ton injection is 7.44x108 Bq or 20 mCi. We use 14C as a tracer
to monitor the CO2 reactivity in the storage reservoir. Its ratio
to carbon in the groundwater of the basaltic aquifer will
change as a result of dissolution and precipitation of carbonate
minerals. Thus, by measuring the carbon isotopic ratio in
water samples collected in monitoring wells, we are able to
quantify and verify in situ mineral carbonation and therefore
long term storage.
[1] Gislason et al. (2010) Int. J. Greenh. Gas Con. 4.
[1] H. Matsuzaki et al. (2010) Radiocarbon 52(2–3), 1487–
1497.
Mineralogical Magazine
1425
www.minersoc.org
1426
Goldschmidt Conference Abstracts
Fluid-flow controls of low " 57Fe
hydrothermal iron mineralization
A. MATTHEWS1*, Y. EREL1, D. STERN1, U.RYB1
2
AND Y. AVNI
Institute of Earth Sciences, Hebrew University of Jerusalem,
Israel (*correspondence: [email protected])
2
Geological Survey of Israel, Jerusalem 95501, Israel
1
Low "57Fe values are characteristic of iron isotope
fractionation during bacterial and abiogenic reduction.
However, experiments on the Fe isotopic fractionation during
sorption-desorption of aqueous Fe on quartz [1, 2] indicate
alternative mechanisms for generating isotopically light iron.
We investigate the controls of Fe-isotopic fractionation
during low temperature hydrothermal iron mineralization
along a 70 km section of a fault (Paran Fault) adjacent to the
Dead Sea Transform (DST), which separates the Arabian plate
from the Sinai Sub-plate. The MVT type mineralization
comprises iron oxide lenses in the fault zone and iron oxidebearing dolomites in the adjacent Cretaceous host rock
limestone. The Mg-Fe rich brines were sourced in evaporitebearing sandstones (Nubian) underlying the limestone.
Fe isotopic compositions from two 10 km long segments
in the west (Haspas) and East (Menuha) parts of the fault show
uniformly negative values: Menuha: "57Fe (Fe-ox) =
-1.08±0.4‰ (n=23); (Fe-dol) = -0.87±0.26‰ (n=15); Haspas
"57Fe (Fe-ox) = -0.86±0.26‰ (n=17); (Fe-dol) = -0.61±0.21‰
(n=13). These values represent isotopically light source
solutions formed by the dissolution of clastic iron minerals in
the sandstone with "57Fe = 0.34±0.19‰. (n=8).
Both bacterial and abiotic reduction of the clastic iron
oxides could have provided isotopically light Fe (II) solutions.
However, the highly saline conditions of the sandstone fluids
do not necesssarily favour bacterial intervention. An
alternative fluid flow model is examined whereby the
isotopically light Fe compositions are generated by sorption
on sandstone grain surfaces. The uniformity of the Fe isotope
composition suggests that fluid flow was generally orthogonal
to the E-W trending fault. Northward fluid flow is consistent
with the topographic recharge being to the south (present-day
Suez Rift) at the Oligocene time of the major pulse of
mineralization. Slightly lighter "57Fe values (8 -1.0 ‰) in
dolomites closer to the DST possibly represent Miocene
reactivation related to creation of the transform [3].
Using atomic force microscopy to
probe pore surfaces of oil-bearing
sandstone
J. MATTHIESEN*, T. HASSENKAM,
N. BOVET AND S.L.S. STIPP
Nano-Science Center, Department of Chemistry, University of
Copenhagen, Denmark
(*correspondence: [email protected], [email protected])
Pore surface properties of oil-bearing sandstone control
the oil recovery from sandstone reservoirs. The wettabillity of
the pore surface, i.e. the tendency of the surface to cover itself
with a fluid, plays a key role in recovery. Pore surface wetting
behavior for chalk reservoirs has previously been shown to be
inhomogeneous over scales of 10’s of nanometers [1]. Here
we investigate whether the same applies for sandstone.
Using atomic force microscopy/spectroscopy (AFM/
AFS), we have probed the surface wetting properties at the
nanoscale of natural oil-bearing sandstones. A self-assembled
monolayer of alkane-thiols is formed on the AFM tip surface,
creating a hydrophobic layer. Force curves measuring the
adhesion between the hydrophobic tip and the sandstone
surface were acquired in a 50x50 grid over a 5x5 µm area
thereby forming a map of adhesion. Properties such as
topography and elasticity were also extracted from these
measurements.
We observe that sandstone wettability varies on a submicrometer scale. In some areas, the degree of adhesion of the
hydrophobic tip decreases with number of scans over the area
and the force curves indicate that material is pulled off the
surface. Using X-ray photoelectron spectroscopy (XPS)
measurements, we saw that the initial surfaces were covered
with several layers of carbon containing material. The wetting
behavior of the pore surface is thus controlled by adsorbed
organic material and not by the actual surface of the mineral.
This improved understanding about the wetting behavior of
reservoir minerals will hopefully provide clues for increasing
oil recovery.
[1] Hassenkam et al. (2009) PNAS 106, 6071–6076.
[1] Matthews et al. (2008) GCA 72, 5908–5919. [2] Mikutta et
al. (2009) GCA 73, 1795–1812. [3] Erel et al. (2006) GCA 70,
5552–5570.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
George R. Tilton and the
development of U-Pb geochronology
Fe –metasomatism in upper mantle
beneath SW Poland
J.M. MATTINSON
Department of Earth Science, Univ. of California, Santa
Barbara, CA 93106-9630 USA
([email protected])
In the early decades of U-Pb geochronology, following the
discovery of radioactivity and the recognition of the decay
products of U decay, ages based on U/Pb ratios were
determined using classical chemical methods. As a result, age
determinations were limited to U ore minerals containing large
amounts of U and Pb. The application of mass spectrometry to
U-Pb studies, e.g. Nier [1, 2], was a major advance, but did
not change the sample requirements -- the early mass
spectrometric methods required several milligrams of Pb per
determination.
From the late 1940’s to the mid-1950’s, George Tilton and
his fellow graduate student at the University of Chicago, Clair
‘Pat’
Patterson
completely
revolutionized
U-Pb
geochronology. They developed the clean chemistry, isotope
dilution, and thermal ionization mass spectrometry techniques
to accurately measure the low concentrations and isotopic
compositions of U, Th, and Pb in meteorites [3] and in
virtually every mineral in a sample of ca. 1 Ga granite [4]. The
new techniques reduced the amounts of Pb required for
accurate measurements of concentration and isotopic
composition by ca. three orders of magnitude, allowing
application of 207Pb/206Pb dating to meteorites and the Earth
[3], and of U-Pb dating to small amounts of zircon, sphene
(titanite), apatite [4] and monazite [5], thus setting the stage
for the modern era of U-Pb geochronology.
[1] Nier (1939) Phys. Rev. 55, 150–153. [2] Nier (1939) Phys.
Rev. 55, 153–163. [3] Patterson et al. (1955) Science 121, 69–
75. [4] Tilton et al. (1955) Bull. Geol. Soc. Amer. 66, 1131–
1148. [5] Tilton & Nicolayson (1956) Geochim. Cosmochim.
Acta 11, 28–40.
1427
M. MATUSIAK-MA9EK1*, J. PUZIEWICZ1,
M. GREGOIRE2AND T. NTAFLOS3
Univ. Wroclaw, Poland
(*correspondence: [email protected])
2
CNRS-UMR 5562, Univ. Toulouse, France
([email protected])
3
Univ. Wien, Austria ([email protected])
1
Cenozoic alkaline volcanic rocks from SW Poland make
the NE termination of Cenozoic Central European Volcanic
Province. The volcanics occur on both sides of the NW-SE
trending Intrasudetic Fault Zone (IFZ), a major Variscan
dislocation feature separating crustal blocks of different
geological record. Two peaks of volcanic activity (30-26 and
23-15 Ma) are recorded in volcanics occurring to the north of
IFZ, whereas Cenozoic eruptive rocks located south from the
fault zone (L:dek Zdrój volcanic field, Kozákov volcano) are
much younger (5 – 3 Ma). All of the mantle xenoliths
occurring in alkaline rocks are from the mantle spinel
peridotite facies.
The xenoliths occurring in volcanic rocks located N of the
IFZ record significant depletion, especially in basaltic
components followed by various style of melt-related
metasomatism. Significant part of peridotites are enriched in
Fe, which is evidenced by low (83-89 %) forsterite content in
olivine, and low #mg in orthopyroxene (0.85-0.86) and locally
cpx (0.87-0.88). Textures of these peridotites exludes
cumulative origin linked to crystal sellting. Some of mineral
chemical features (e.g. NiO in Ol 0.30 – 0.44 wt.%) indicate
upper mantle origin. We suggest that the Fe – enriched
peridotites represent parts of mantle affected by Fe (and Mn) –
rich metasomatic agent, which appearts to be alkaline silicate
melt in the Ksi;ginki locality [1]. Lack of bulk rock Ca
enrichment, typical for other Fe – peridotites [2] suggests low
fraction of carbonated-eclogite-derived melts [3, 4] to be a
metasomatic agent in Krzeniów locality.
The Fe-enriched peridotites among mantle xenoliths have
not been found to the south of IFZ (L:dek Zdrój [3], Kozákov
[5]). Moreover, xenoliths from the southern and northern
domains differ in respect to texture, modal composition and
style of metasomatic processes. Hence, we suggest that IFZ
constitutes also a boundary between two litospheric mantle
domains.
[1] Puziewicz et al. (submitted) J Petrol. [2] Ionov (2005)
Contr Miner Petr 150, 335–353. [3] Dasgupta et al. (2006)
J Petrol 47, 647–671. [4] Matusiak-Ma<ek et al. (2010) Lithos
117, 49–60. [4] Ackerman et al. (2008) J Petrol 48, 2235–
2260.
Mineralogical Magazine
www.minersoc.org
1428
Goldschmidt Conference Abstracts
Analysis of heavy metals in
floodplains of the Morava and Jizera
rivers
Acquisition of Fe by aerobic
microorganisms: Effects of Fe oxide
nanoparticle size
TOMAS MATYS GRYGAR2, TEREZA NOVAKOVA1,2*,
VERONIKA LUKESOVA2,3 AND MARTIN MIHALJEVIC1
Charles University, Faculty of Science, Albertov 6, 128 43,
Prague ([email protected])
(*correspondence: [email protected])
2
Institute of Inorganic Chemistry AS CR ([email protected])
3
Department of Soil Science and Soil Protection, Faculty of
Agrobiology, Food and Natural Resources, Czech
University of Life Sciences in Prague
([email protected])
1
Regional pollution by Cu, Pb and Zn during the 20th
century was studied in floodplains of two rivers in Czech
Republic, usually considered less contaminated - the Morava
and the Jizera; the latter is one of three water sources for
Prague. Sediments were obtained by hand-drilled cores (2-4 m
long) and in the case of the Morava River from outcrops in
erosion banks. To describe realistically the pollution of
floodplain sediments, facial analysis and outline of floodplain
architecture are essential for two main reasons: to distinguish
anthropogenic impact from natural background and evaluate
possible
post-depositional
migration
of
pollutants.
Geochemical analysis by laboratory ED XRF spectrometer
offers handy tools for both these subtasks, which we have
learnt in the Morava River floodplain and now apply to Jizera
River floodplain. Additional subtask is sediment dating, which
can be achieved by careful examination of depth dependences
of activities of 137Cs and unsupported 210Pb; the use of 14C of
plant debris is, unfortunately, limited. For reliable
reconstruction of the past pollution, fine sediments (silty clay
with small sand content) should be used, which slow down the
vertical migration of both pollutants and 137Cs. Cu, Pb and Zn
start to migrate substantially in floodplain sediments of both
studied rivers at depths larger than 1.5 m, where they follow
lithofacial boundaries and redox accumulations of Fe and Mn
oxides. Extensive correlations of densely and continuously
sampled cores must be performed to avoid lithofacial biases
and migration - and only that can allow sound interpretations.
Approximate dating of sediments from the Morava River area
can be based on the onset of Pb and Zn contamination at about
1900, Pb fastest enhancement at moderate Zn in the 1950's,
stagnating Pb 1960’s – 1980’s), and stagnating Zn and
declining Pb since 1990's.
Mineralogical Magazine
P.A. MAURICE1, C. DEHNER2,
J. DUBOIS2 AND L.E. BARTON1
1
2
Dept. of Civil Engineering & Geological Sciences, and
Dept. of Chemistry and Biochemistry, University of Notre
Dame, Notre Dame, IN, 46556, USA ([email protected],
[email protected], [email protected], [email protected])
Most organisms require Fe as a fundamental nutrient; yet,
Fe-bearing minerals tend to be highly insoluble in circumneutral aerobic environments. Many aerobic microorganisms
overcome Fe limitation by releasing low molecular weight
organic ligands known as siderophores into the environment.
Siderophore-Fe(III) 1:1 complex stability constants range
from 1023-1052.
Using an obligate aerobic bacterium Pseudomonas
mendocina ymp wild type (WT) and a siderphore (-) mutant of
the species (MT; i.e. a mutant that can not produce
siderophore), along with a reporter strain that signals Fe
deficiency, our group investigated Fe acquisition from
hematite (nano)particles of different average particle sizes. Fe
associated with < 10 nm hematite was considerably more
bioavailable than Fe associated with larger particles. Hematite
nanoparticles < 10 nm have more transient or labile Fe,
dissolve at about an order of magnitude faster rate in
siderophore at circumneutral pH, and support enhanced
growth (relative to growth on 72 nm hematite) by P.
mendocina WT under Fe-limited conditions. The greater
bioavailability is also related in part to mechanism (s) that
depend on cell/nanomineral proximity, but not on
siderophores. MT bacteria readily acquire Fe from particles <
10 nm but must be in direct physical proximity to the
nanomineral. Addition of the reducing ligand ascorbate is
particularly effective at supplying nano-hematite Fe to the
bacteria under siderophore-free conditions. Even a small
amount of cell-surface associated reducing activity, as further
suggested by results of ferrozine assay, therefore would be
likely to enhance cell growth considerably.
www.minersoc.org
Goldschmidt Conference Abstracts
P-T-t evolution of metapelitic rocks
from the Bushveld contact aureole:
Using garnet isopleths
thermobarometry and Lu-Hf garnet
dating
P.K. MAVIMBELA*, M.J. RIGBY, P.G. ERIKSSON
AND P. GRÄSER
University of Pretoria, Pretoria 0002, South Africa
(*correspondence [email protected],
[email protected], [email protected],
[email protected])
We employ garnet isopleth thermobarometry and Lu-Hf
garnet isotopic system in order to investigate the P-T-t
evolution of two garnet bearing metapelitic samples (DY954
and DY918) from the Bushveld contact aureole. Two types of
garnets porphyroblast were identified in sample DY954,
garnet included in biotite which records peak metamorphic
condition of 551 ±150C at 3.1±0.2kb and a non reactive garnet
which records 527±80C at 3±0.35kb. The slightly higher
temperature of the former may be interpreted to have resulted
from garnet reaction overstepping. The DY918 amalgamated
garnet porphyroblast does records different P-T conditions
(~6010C at 1.3kb) as compared to the DY954 sample and the
fusion of the garnets which will require significant recrystallization [1] can be attributed to these higher
temperatures. The weighted average Lu-Hf garnets isochron
ages obtain for the two samples (DY954 and DY918) are
2061.5±5.1Ma and, 2061.4±3.5Ma respectively. The nearly
identical garnet isochron ages marks the first robust age of the
BIC contact aureole which can be indirectly interpreted as
constraints to the emplacement age of the RLS.
[1]Taylor, J. & Stevens, G. (2010) Lithos 120, 277–292.
Mineralogical Magazine
1429
Heavy metal fractionation in high
temperature fumaroles
JOHN A. MAVROGENES* AND RICHARD W. HENLEY
Research School of Earth Sciences, Australian National
University, ACT Australia 0200
(*correspondence: [email protected])
Some volcanoes discharge high temperature gases from
which unique metal suites are formed as sublimates. Examples
include Vulcano, Italy, where sublimates contain a wide range
of rare bismuth-lead sulfosalt minerals. Paradoxically, arsenic
minerals do not occur in fumarole discharges but are common
in crater lakes. In paleo-fumarole environments such as
Chinkuashih, Taiwan, enargite and related sulfosalts occur as
almost mono-mineralic assemblages over a depth range of
more than 1000 meters. Modelling of vapor-phase stabilities
shows that decompressing volcanic gases deposit pyrite below
700oC followed by rapid precipitation of enargite as
depressurization proceeds. In consequence, surface discharges
are strongly depleted in arsenic, iron, copper and a range of
heavy metals.
Based on high resolution microanalysis of As-rich
sulfosalt assemblages in paleo-fumaroles, we suggest that
fractionation occurs between arsenic-rich sulfosalt melt and
vapor within the upper few hundred meters of the surface,
leading to heavy metal (Sb, Bi, Te, etc) enrichment of the
vapor phase and consequent formation of lead-bismuth
sulfosalt minerals and tellurides in surface discharges, such as
the metallic snow of the Venus Highlands region. Similar subsurface fractionation processes result in molybdenum-rhenium
enrichment in volcanic systems such as Kudryavy (Kurile Arc,
Russia), and gold and silver in others (e.g.Kudryavy and
Colima, Mexico). Similar sulfosalt –sulfide melt segregation
occurs in the magmatic environment resulting in metal
fractionation during the formation of the so-called ‘high
sulfidation’ and porphyry copper-gold deposits.
www.minersoc.org
1430
Goldschmidt Conference Abstracts
Effect of aqueous organic ligands on
Mg-isotope fractionation during
magnesite precipitation
V. MAVROMATIS*, Q. GAUTIER, J. SCHOTT
AND E.H. OELKERS
Geoscience and Environment Toulouse (GET), CNRS, UMR
5563, OMP, 14 Avenue Edouard Belin, 31400 Toulouse,
France (*correspondence: [email protected])
Organic ligands are present in most Earth’s surface
environments and play a significant role on mineral formation
and transformation. This study aims to illuminate the effect of
the presence of these organic ligands on isotopic fractionation
during mineral dissolution and growth.
Magnesite precipitation experiments were conducted in
mixed flow reactors at 120 and 150 oC following the methods
described by Saldi et al. [1], in the reactive fluids containing
various concentrations of aqueous oxalate and citrate.
Supersaturation of the reactive fluid in the reactor was
facilitated by the retrograde solubility of magnesite. Magnesite
precipitation favored incorporation of isotopically lighter Mg
into solid phase, as shown by enrichment of 26Mg in the outlet
solutions. Experiments conducted at 120 oC show larger
isotopic fractionation factors =26Mgsolid-solution compared to
those performed at 150 oC indicating a temperature effect on
isotopic fractionation. Furthermore, experiments performed in
the presence of oxalate and citrate, exhibit lower =26Mgsolidsolution values at similar precipitation rates compared to
corresponding experiments performed in the absence of
aqueous organic ligands. These observations suggest the
preferential complexation of the heavier Mg isotopes by the
organic ligands in aqueous solution.
Overall the observations obtained in this study
during
magnesite
demonstrate
that
=26Mgsolid-solution
precipitation depends not only on precipitation rates, but also
on the concentration of aqueous organic ligands. This result
suggests that the presence of organic ligands may also effect
the isotopic fractionation of a large number of other elements,
and may be responsible, at least in part for the degree of
isotopic fractionation observed in natural systems.
[1] Saldi et al. (2009) Geochim. Cosmochim. Acta 73, 5646–
5657.
Sm-142,143Nd studies of komatiites
from western Dharwar Craton,
India: Implications for depleted
mantle evolution in Early Archean
146,147
J.M. MAYA, RAJNEESH BHUTANI*
AND S. BALAKRISHNAN
Department of Earth Sciences Pondicherry University,
Puducherry 605014
(*correspondence: [email protected])
Early Earth Differentiation
Variation of 142Nd/144Nd ratio in terrestrial samples
compared to chondrites has now been demonstrated by several
studies indicating an early global chemical differentiation of
Bulk Silicate Earth (BSE). (see [1] for a recent review).
These studies, however, raised several outstanding
questions related to nature of Early Enriched Reservoir (EER)
and Early Depleted Mantle (EDM) and their subsequent
evolution.
Results
We have carried out measurements of 142Nd/144Nd ratios,
along with conventional 147Sm-143Nd studies, on well
preserved komatiites with spinifex texture characterized by
MgO > 20% that occur at Banasandra, in the western limb of
Chitradurga greenstone belt of Dharwar craton in India.
142
Nd/144Nd ratios of these komatiites are same as La Jolla
and AMES standards within 10 ppm (2 !) uncertainity. The
147
Sm-143Nd whole rock isochron age as yielded by 9 samples
is 3136 ± 200 Ma (MSWD =74) with initial 143Nd/144Nd
=0.50872 ± 0.00033 corresponding to 0Nd (t=3.15)=+ 3.5.
Discussion
We calculated time-integrated 147Sm/144Nd ratio of source
of 3.15 Ga old komatiites of Dharwar craton with the
constraints that it got differentiated at 4.2 Ga (No radiogenic
142
Nd/144Nd anomaly) and that by 3.15 Ga ago it evolved to
0Nd (t=3.15)=+ 3.5. The time-integrated 147Sm/144Nd ratio of the
source, thus obtained, is significantly higher than what has
been predicted by Blichert-toft and Puchtel [2] for the source
of this age. These results can be explained if source of these
komatiites is originated from a second differentiation of the
EDM at 4.2 Ga. Further, these results also indicate that
Archean depleted mantle has not been homogenous in time
and space.
[1] Caro G (2011) Annu. Rev. Earth Planet. Sci.! 39, 31–58.
[2] Blichert-Toft & Puchtel (2010) Earth & Planetary Science
Letters 297, 598–606.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Variability of nitrogen stable isotope
in suspended organic matter in
waters of the western continental
shelf of India and the Mandovi
estuary
M.V. MAYA1*, S.G. KARAPURKAR1, M.A. SOARES1,
R. AGNIHOTRI2, R. ROY1, H. NAIK1 AND S.W. A. NAQVI1
National Institute of Oceanography (Council for Scientific
and Industrial Research), Dona Paula, Goa - 403004, India
(*correspondence: [email protected])
2
National Physical Laboratory, New Delhi, India
([email protected])
1
First direct evidence for the addition of substantial amount
of isotopically light nitrogen by Trichodesmium in the western
continental shelf of India (WCSI), a region of global
significance on account of being the largest natural seasonallyoccurring coastal oxygen-deficient zone in the world with
large efflux of N2O to the atmosphere. The results for the
WCSI and the Mandovi estuary are summarized in Fig. 1,
which reveal significant shifts in "15N of suspended particulate
organic matter (SPOM) before and after the onset of the southwest (SW) monsoon.
Discussion of results
The development of Trichodesmium blooms significantly
lowers the "15N of SPOM during the pre-monsoon season,
whereas water-column denitrification makes SPOM enriched
in "15N during late SW monsoon. Another important result of
this study states that the "15N of SPOM is generally lower than
the mean value (7.38‰) for surficial sediments. The "15N of
SPOM in the Mandovi estuary also shows significant variation
during and after the cessation of SW monsoon. Depletion of
&15N in SPOM during the SW monsoon could be preferential
utilization of 14NO31 by phytoplankton, as has been observed
in other NO31 replete areas, whereas post-monsoon season are
characterized by relatively high "15N of SPOM.
AB
Figure 1: A) Intra-annual variations in "15N of SPOM along
the WCSI. B) SW monsoon and post-monsoon changes in the
Mandovi estuary.
Mineralogical Magazine
1431
Isotopic analysis of microarrays to
link microbial identity and function
X. MAYALI1*, P.K. WEBER1, E.L. BRODIE2, S. MABERY1,
P.D. HOEPRICH1 AND J. PETT-RIDGE1
Lawrence Livermore National Laboratory, Livermore CA
94550, USA (*correspondence: [email protected])
2
Lawrence Berkeley National Laboratory, Berkeley CA 94720
USA
1
Most microorganisms remain uncultivated, and typically
their ecological roles are inferred from diversity and genomic
studies. To directly measure functional roles of uncultivated
microbes, we developed Chip-SIP, a high-sensitivity, highthroughput stable isotope probing (SIP [1]) method performed
on a phylogenetic microarray. For this approach, we incubate
microbial communities with isotopically labeled substrates,
hybridize community rRNA to a microarray, and measure
isotope incorporation—and therefore substrate use—by
secondary ion mass spectrometer imaging (NanoSIMS).
Chip-SIP analysis of an estuarine community quantified
amino acid, nucleic acid or fatty acid incorporation by 81 taxa.
The resulting resource use profile (Figure 1) demonstrates that
some generalist bacteria can incorporate multiple organic
substrates while others specialize in 1 or 2 out of 3. We also
found that bacterial functional capacity can be decoupled from
phylogeny. This approach provides a means to test genomicsgenerated hypotheses about biogeochemical function in
natural environments.
Figure 1: summary network diagram of Chip-SIP analysis of
San Francisco Bay, linking substrates (circles) to microbial
taxa (ovals). The thickness of the lines is proportional to the
amount of substrate incorporated.
[1] Radajewski et al. (2000) Nature 403, 646–649.
www.minersoc.org
1432
Goldschmidt Conference Abstracts
Absolute isotopic composition of
molybdenum reference materials
using double spike MC-ICP-MS
A.J. MAYER1*, B. PROEMSE2 AND M.E. WIESER1
Chemical and isotopic composition of
Cenozoic hornblende-bearing basalts
from the Rhön area (Germany)
B. MAYER1*, S. JUNG1 AND A. STRACKE2
1
Department of Physics and Astronomy, 2500 University
Drive NW, University of Calgary, Calgary, AB, T2N 1N4,
Canada (*correspondence: [email protected])
2
Department of Geoscience, 2500 University Drive NW,
University of Calgary, Calgary, AB T2N 1N4, Canada
Mineralogisch-Petrographisches Institut, Universität
Hamburg, Grindelallee 48, 20146 Hamburg, Germany
(*correspondence: [email protected])
2
Westfälische Wilhelms Universität, Institut für Mineralogie,
Correnstraße 24, 48149 Münster, Germany
Molybdenum isotope abundance measurements have
enabled unique insights into the study of oxic conditions in the
oceans [1], high-temperature hydrothermal ore deposits [2],
and the heterogeneity of molybdenum in the early solar system
[3]. Useful interpretations are only possible when isotopic
compositions are reported relative to commonly available
reference materials. Chemical processing of samples can alter
isotopic composition, so it is important to test methods on
matrices of known molybdenum isotopic composition and
concentration.
At present, researchers are using a variety of commercially
available and in-house standards. Recently, Wen et al.
measured the relative isotopic composition of five reference
solutions and proposed using NIST SRM 3134 as the delta
zero reference for molybdenum [4]. However, the absolute
isotopic compositions of these standards were not reported and
none of the chosen materials were in a natural matrix.
In this study, we have determined the absolute isotopic
composition of molybdenum in a variety of reference
materials including NIST SRM 3134, BCR-1, BCR-2 (basalt),
USGS SCo-1 (shale), SRM 1547 (peach leaves), JohnsonMatthey pure Mo metal rod, and SCP Science Mo PlasmaCal.
Measurements were made using a Thermo Scientific Neptune
MC-ICP-MS. Instrumental fractionation was corrected by
measuring a mixture of the sample with a fully calibrated
double spike. The fractionation correction assumed an
exponential fractionation law and used computational root
finding methods to solve for the fractionation due to chemical
processing and instrumental mass bias.
Primitive, alkaline mafic volcanic rocks provide important
information about the chemical composition of the Earth’s
mantle. The source of intra-continental volcanic rocks are
either the subcontinental lithospheric mantle, the
asthenospheric upper mantle or upwelling mantle material
(mantle plumes). In contrast to the asthenosphere, the
lithospheric part of the mantle has been isolated from the
convecting part and may have had a complex geological
history of ancient depletion and enrichment events.
Unusual hornblende-bearing basanites from the Rhön area
(Central European Volcanic Province; CEVP) are mostly
primitive to differentiated volcanic rocks (Mg#: 65-45, Ni:
190-60 ppm, Cr: 400-100 ppm) with higher TiO2, lower MgO
contents and slightly lower Ce/Pb ratios (15-20) at a given
SiO2 content relative to other alkaline rocks from the CEVP.
Rare Earth element patterns show LREE enrichment but only
moderate depletion in HREE relative to primitive mantle. Rare
earth element patterns can be reproduced by about 4 to 8 %
partial melting of a spinel peridotite containing 10 % of modal
amphibole. In multi-element diagrams, the basanites are
enriched in Nb, but depleted in Rb and K relative to the
neighboring elements, compatible with partial melting with
residual amphibole.
Incompatible trace element abundances and ratios and Nd
and Sr isotopes overlap those of other volcanic rocks from the
CEVP. Initial 87Sr/86Sr ratios range from 0.7034 to 0.7040 at
almost constant initial 143Nd/144Nd of ca. 0.51279-0.51285
(!Nd of +3.3 to +4.6). The Sr and Nd isotope data suggest that
contamination of the lavas with the ambient lower crustal
rocks is relatively minor (< 5%). The variable Sr at constant
Nd isotope compositions could also result from melting
heterogeneous sources with variable Rb/Sr ratios as a result of
mantle metasomatism. Based on their high TiO2 but low MgO,
elevated 87Sr/86Sr ratios and low Ce/Pb ratios relative to other
basanites from the CEVP, the hornblende-bearing basanites
appear to contain a signifcant proportion of the lithospheric
upper mantle.
[1] Barling et al. (2001) EPSL 193, 447–457. [2] Mathur et al.
(2010) Miner Deposita 45, 43–50. [3] Dauphas et al. (2002)
ApJ. 565, 640–644. [4] Wen et al. (2010) J. Anal. At.
Spectrom. 25, 716–721.
Mineralogical Magazine
1
www.minersoc.org
Goldschmidt Conference Abstracts
Modeling the relationship between
sorption and residence times
The effect of M. thermoflexus on the
Fe-bearing mineral assemblage
associated with low temperature
basalt-water reactions
M.A. MAYES*, S. JAGADAMMA, W.M. POST,
J. FRERICHS AND G. WANG
P.O. Box 2008, Oak Ridge, TN 37831
(*correspondence: [email protected])
We seek to improve representations of stabilization and
degradation of organic carbon in soils in terrestrial C cycling
models. Major processes considered in the model include
sorption of dissolved compounds onto mineral and particulate
soil fractions, incorporation into microbial biomass, enzymefacilitated degradation, and mineralization of dissolved and
native carbon. Soils from temperate, tropical, and arctic
climates will be used. The sorptive capacity of three orders of
magnitudes of dissolved compounds common to soil solutions
(sugars, starch, lipids, etc.) will be measured using 14C
labelling. Subsequently, the soils containing adsorbed
compounds will be subjected to short-term incubation
experiments to determine rates of mineralization from each
soil fraction. Chloroform fumigation will be used to measure
14
C allocated to microbial biomass. Enzyme assays will be
used to determine the potential for enzyme activities in
response to various treatments. This presentation will consist
of initial experimental findings and presentation of the model
framework. The initial findings will be evaluated in terms of
project goals produce a testbed for modelling microbiallyfaciliated sorptive and degradative processes at the soil
mineral interface.
Mineralogical Magazine
1433
L. MAYHEW1*, G. LAU1, T. MCCOLLOM2
1
AND A. TEMPLETON
Dept. Geological Sciences, University of Colorado–Boulder
(*correspondence: [email protected])
2
Laboratory for Atmospheric and Space Physics, University of
Colorado–Boulder
1
Water-rock reactions, such as serpentinization of
ultramafic rocks in the ocean crust, alter Fe(II)-bearing silicate
minerals producing secondary minerals and H2 gas and are
therefore thought to support chemolithotrophic life in extreme
environments (e.g. the deep subsurface). However, the
alteration of Fe-bearing silicate minerals present in these rocks
has not been extensively studied under low temperature,
anoxic conditions. We inoculated a low temperature (55°C),
anoxic water-Fe0-basalt system with a methanogenic
Archaeon, to determine if 1) microbial growth could be
supported by in situ production of H2 gas and 2) the presence
of the microorganisms influenced the production of H2 gas and
the Fe-bearing secondary mineral assemblage.
Growth of M. thermoflexus is evidenced by time series
measurements of H2 and CH4 showing the continuous
production of H2 in the abiotic control while in cultures
microbial methanogenesis draws down H2 and produces CH4.
Upon saturation, purging the headspace gases destabilizes Febearing minerals and releases Fe and Si to solution. [Si(aq)],
while buffered to relatively constant values, was lower in the
abiotic control than cultures. [H2] appears to affect the
speciation of Fe in the solid phase products. Collection of
synchrotron-based µXRF maps at multiple energies within the
Fe K-edge and µXANES analyses integrated with principal
components analyses and XANES fitting enables visualization
and quantification of the distribution of the Fe-species. After
~1 year of reaction, Fe-bearing secondary mineral
assemblages associated with high [H2] (abiotic control) are
different than those associated with low [H2] (culture
experiments). For example, minnesotaite, an Fe-phyllosilicate,
is ubiquitous in the abiotic control but much less abundant in
the culture experiments. We will discuss how the geochemical
reaction paths and Fe-speciation differ between the abiotic
control and the culture experiments. This work suggests that at
low temperatures microorganisms may have a profound effect
on what has long been thought to be solely an abiotic reaction
and may produce diagnostic mineral assemblages that may be
preserved in the geological record.
www.minersoc.org
1434
Goldschmidt Conference Abstracts
The petrological, geochemical and
tectonic setting of metabasites from
Mashhad, North East of Iran
Importance of syntrophic acetate
oxidation during thermophilic
municipal solid wastes anerobic
digestion
S.A. MAZAHERI1, R. BIERESDORFER2
2
AND F. ARMSTRONG
Geology Department, Faculty of Sciences, Ferdowsi
University of Mashhad, Mashhad, 91775-1436, Iran
2
Department of geological and Environmental Studies,
Youngstown State University, Ohio 44555, USA
([email protected])
L. MAZEAS1*, J. GROSSIN-DEBATTISTA1, X. QU1,2,
A. GUENNE1, P.J. HE2, H. BUDZINSKI3, M. LE MUNIER4
1
AND T. BOUCHEZ
1
Metabasites of Mashhad area are part of Virani
(Nourabad) Ophiolite in the Binaloud region. The ophiolite
extends to Aghdarband area, north east of Fariman. Ultramafic
rocks are predominantly peridotite (lherzolite, wherlite and
hursburgite). Mafic rocks are mainly metabasalt, metagabbro
and metadolerite. Large pillow lavas (>45 Cm in diameter)
crops out in Zakaria and Nowdarreh areas.
Metabasites subjected to a low to medium grade
metamorphism (greenschist to amphibolites facies),
characterized by Ab + Act + Epid + Chlo; Na-Plag + Hbld +
Epid and Ca – Na Plag + Hbld assemblages. Plagioclase (Ab
to Ande), Amphiboles (Actinolite and Hornblende), Epidote,
Chlorite, Quartz, Sphene, Apatite and Iron – Oxides are the
most common minerals of metabasites.
Selected samples have analysed by XRD, XRF and ICP
methods. Major and trace elements data indicates that
metabasites are tholeiitic in nature and characterized by low
potassium (0.25 wt%), and high magnesium (maximum 23.23
wt%), high chromium (maximum 2110 ppm), and high nickel
(maximum 2970 ppm) contents. The metabasite samples have
low Zr/TiO2 (0.0011 – 0.0092) and Nb/Y (0.06 – 0.15) ratios,
similar to those of tholeiitic basalts.
The Metabasites of Mashhad area are believed to be
remnant of the Paleo – Tethys oceanic plate that were
subducted beneath the Turan plate. Later on the Turan plate
have obducted over the Iranian Micrcontinent, and formed the
northeasten Iran.
Mineralogical Magazine
Cemagref-HBAN, parc de Tourvoie, BP 44, 92163 Antony
cedex, France
(*correspondence: [email protected])
2
State Key Laboratory of Pollution Control and Resources
Reuse, Tongji University, Shanghai 200092, China
3
Institut des Sciences Moléculaires (ISM) – UMR 5255 CNRS
- Université Bordeaux 1, 33405 Talence, France
4
Suez Environnement, CIRSEE, 38 rue du Président Wilson,
78230 Le Pecq, France
1
During anaerobic digestion of organic matter, acetate and
H2/CO2 are expected to be responsible of around 67% and
33% of the methane production respectively [1]. Our results
show that temperature has a significant influence on
methanogenic pathways as indicated by the different CH4
isotopic composition (&13CH4) evolutions observed under
mesophilic and thermophilic conditions. The contribution of
the hydrogenotrophic pathway appears to be much more
important in thermophilic condition due to the occurrence of
the syntrophic acetate oxidation (SAO) reaction.
Using different molecular microbiological tools
(Fluorescent in situ hybridization and cloning sequencing)
microbial communities involved during those MSW
incubations have been identified. It appears that strict
hydrogenotrophic archaea from the Methanomicrobiales order
are highly dominant in thermophilic condition which is in
accordance with a SAO reaction implication.
[1] Conrad (1999) FEMS Microbiol Ecol 28, 193–202.
www.minersoc.org
Goldschmidt Conference Abstracts
Petrogenesis of Zoozan pluton, NE of
Lut, Eastern Iran
S.A. MAZHARI1* AND M. SAFARI2
Department of Geology, Payame Noor University, 193954697 Tehran, I.R. of Iran
(*correspodence: [email protected])
2
Geological Survey of Iran, North-East Territory, Mashhad,
Iran ([email protected])
1
The Zoozan pluton is one of the Tertiary plutonic bodies
in the northeastern of the micro-continental Lut block in
Eastern Iran. This pluton is composed of two geochemically
unrelated mafic and granitoid units. All rocks are calcalkaline, with LILE/REE and HFSE/REE compatible with arc
magmas. Mafic phase consists of gabbro to quartz diorite and
emplaced as small stocks and dykes. These rocks exhibit
relatively high contents of incompatible elements, low Na2O
and Mg#>44.0. These features suggest their origin from
enriched lithospheric mantle above subducted slab.
Granitoid phase includes granite-granodiorites which
show high-K calc-alkaline metaluminous to slightly
peraluminous I-type granitoid characteristics. Their Chondritenormalized REE patterns mark enrichment of LREE
(LaN/LuN= 7.6-12.5) and small negative anomaly (Eu/Eu*=
0.63-0.74). They have geochemical composition typical of
volcanic arc granitoids and have been originated from
metabasaltic to tonalitic sources. Furthermore, fractional
crystallization may have played significant role during the
formation of Zoozan granitoids.
Variation in carbon stable isotope
ratios of organic matter in Bay of
Bengal during the last glacial episode
A.MAZUMDAR*, R.K. JOSHI, A. PEKETI AND B.G. NAIK
Geological Oceanography, National Institute of
Oceanography, Donapaula, Goa, 403004, India
(*correspondence: correspondence: [email protected])
We report here a high resolution total organic carbon
content (TOC) and "13CTOC variations from a 30m long core
from Bay of Bengal. The core (MD161-8, water depth: 1033
m) was collected on board Marion Dufresne as part of our on
going gas hydrate exploration program in the KrishnaGodavari basin. TOC content is constrained within 1-2 wt%.
Our studies show dependence of TOC content on grain size
distribution. During the last glacial episode, the "13CTOC varied
between 14 and 17‰ VPDB indicating a significant
contribution of C4 vegetation. Within 16-18 mbsf we have
observed presence of pentamethyl icosane with carbon isotope
ratios <-100‰. Presence of PMI has resulted in the isotope
excursion. Post LGM rise in pCO2 resulted in the diminished
C4 contribution. Most depleted C isotope ratio is noted at ~7-8
ky BP suggesting enhanced contribution of terrestrial organic
matter. For rest of the Holocene contribution from marine
productivity dominates.
Figure 1: TOC and "13CTOC profile of MD161-8
Mineralogical Magazine
1435
www.minersoc.org
1436
Goldschmidt Conference Abstracts
Pristine mantle xenoliths from the
active Bismarck Arc
SARLAE R.B. MCALPINE* AND RICHARD J. ARCULUS
Research School of Earth Sciences, Australian National
University, ACT Australia 0200
(*correspondence: [email protected])
Peridotites samples were recovered during the Marine
National Facility Voyage (SS06-2007; WeBiVE) from three
volcanic cones northwest of Ritter Volcano, New Britain-West
Bismarck Arc system of Papua New Guinea. Wedge-derived
peridotites are extremely rare even in well-explored subaerial
arcs; the Ritter suite is the first global occurrence of
peridotites recovered from an active submarine volcanic arc
front edifice.
The peridotites occur as rounded (815cm diameter) and
angular blocks and fragments. The host basalt is a Cr spinelolivine-diopsidic augite-bearing, medium-K tholeiite. It is the
most MgO-rich basalt (~15wt%) reported in the WestBismarck-New Britain Arc system; the high-MgO might
derive in part from the cumulative and/or xenocrystic nature of
some olivine.
The xenoliths are pristine (serpentine-free), predominantly
harzburgitic but also include lherzolite, orthopyroxenite, and a
single gabbro. Preliminary petrological analysis shows
complex textural relationships between the constituent
minerals olivine (Fo94.4-86.3), orthopyroxene, clinopyroxene,
and spinel. The spinel is highly refractory with Cr/(Cr+Al) >
0.9 accompanied by high Mg/(Mg+Fe2+) consistent with
quenching from high-temperature. Deformation textures
include olivine kink-banding and wavy exsolution lamellae in
the pyroxene. Secondary clinopyroxene reflects some
metasomatism. Bulk trace element charateristics include
relatively unfractionated rare earth element abundances (0.6 to
1*chondritic), elevated Pb/Ce (>1), and negative Nb, Ta, Zr,
Hf, and Ti anomalies.
Temperatures range from ~900 to 1100 °C; fO2 ranges
from >FMQ -2 to +0.5. These samples show extremely
refractory, relatively reduced harzburgites are present in the
mantle section beneath a modern subduction system. Ongoing
detailed mineralogical and petrological studies will provide
important insight into the mantle below the New Britain-West
Bismarck Island Arc.
Mineralogical Magazine
Arsenic in Ground Water
J.M. MCARTHUR
Earth Sciences, UCL, London WC1E 6BT, UK.
([email protected])
Arsenic in groundwater presents a hazard to health
globally [1]. In the Bengal Basin, one of the regions worst
affected by such pollution [2, 3], the distribution of pollution
reflects the geological evolution of the basin during the past
125,000 years [3], and the same explanation, with local
modifications, must apply to As-polluted deltaic aquifers
worldwide. The As-pollution is confined largely to sediments
laid down after the last glacial maximum, a fact that explains
the vertical inhomogeneity in As-pollution. The lateral
inhomogeneity in As-pollution reflects, in part, the distribution
of As-polluted palaeo-channel aquifers and As-free palaeointerfluvial aquifers [4].
Flow of As-polluted palaeo-channel water into As-free
palaeo-interfluvial aquifers has been ongoing since sea-level
stabilized around 6 ka. The flow has been accelerated by
abstraction of water for irrigation since the 1970s. Natural and
enhanced flows explain the development of a strong redox
gradient at the palaeo-interfluvial margins. Flows enhanced by
abstraction for irrigation explain rising concentrations of As in
marginal palaeo-interfluvial wells, especially where the flow
is counter to the natural hydraulic gradient. In this talk, some
of these aspects will be explored.
[1] Ravenscroft, P. et al. (2009) .Arsenic pollution: a global
synthesis. Wiley-Blackwell [2] Frisbie SH, et al. (1999) The
nature and extent of arsenic-affected drinking water in
Bangladesh. In: Metals and Genetics (Sarkar B, ed). New
York: Plenum Publishing Co,; 67–85. [3] DPHE; (1999)
Groundwater Studies for Arsenic Contamination in
Bangladesh. Final Report, Rapid Investigation Phase.
Department of Public Health Engineering, Government of
Bangladesh. Mott MacDonald and British Geological Survey
(6 vols), Dhaka [4] McArthur J.M. et al. (2011). Palaeosol
control on groundwater flow and pollutant distribution: the
example of arsenic. Environ. Sci. Technol., 45, 1376–1383.
dx.doi.org/10.1021/es1032376.
www.minersoc.org
Goldschmidt Conference Abstracts
Serpentinization and hydrogen
generation
Reaction rind formation in Mèlange
in the Catalina Schist, California
C.A. MCCALLUM *,
S.C. PENNISTON-DORLAND1 AND G.E. BEBOUT2
1437
T.M. MCCOLLOM1, F. KLEIN2, W. BACH3,
N. JÖNS3 AND A. TEMPLETON4
1
Department of Geology, University of Maryland, College
Park, MD 20742, USA
(*correspondence: [email protected])
2
Department of Earth and Environmental Sciences, Lehigh
University, Bethlehem, PA 18015, USA
Laboratory for Atmospheric and Space Physics, University of
Colorado, Boulder, 80309, USA
([email protected])
2
Woods Hole Oceanographic Institution, MA, USA
3
University of Bremen, Germany
4
University of Colorado, Boulder, CO, USA
Reaction rinds between differing lithologies are commonly
thought to have formed due to fluid-assisted metasomatic
alteration, however, enrichment in relatively fluid-immobile
elements such as Cr and Ni suggests an additional process
may be responsible for their formation. Eleven samples along
a 17cm transect through one amphibolite grade block and a
reaction rind with an ultramafic-rich matrix from the Catalina
Schist, CA show distinct changes across the block-rind contact
in mineral abundance and whole rock major and trace element
and Li isotope composition. Whole rock rind concentrations of
SiO2, K2O, Rb, Ba, MgO, Cr and Ni are enriched in the rind
relative to the core and FeO is depleted. Lithium
concentrations are enriched in the rind (10-16ppm) relative to
the core (8-11ppm) with "7Li ranging from -3 to +1‰. The
distribution of Li concentrations and isotope compositions is
consistent with diffusion on the scale of almost the entire 17cm profile. Garnets in the core and rind are similar in FeO
content, however whole-rock FeO of the core and rind differs
significantly, suggesting garnet growth before the depletion in
whole-rock FeO. Rind garnets are pseudomorphed extensively
by decussate chlorite, suggesting that infiltration by H2O-rich
fluid occurred after garnet growth. Rind concentrations of Cr,
Ni Al2O3 and CaO can be most simply explained by
mechanical mixing of mafic block (50-70%) with melange
matrix (30-50%). Mixing cannot explain the increases in SiO2,
K2O, Li, Rb and Ba or the depletions in FeO, and we propose
that the concentrations of these elements in the rind are due to
relatively late-stage fluid infiltration. We propose an early
episode of mechanical mixing where mixing of mafic block
and melange matrix produced rind-like material which was
then accreted onto the outside of basaltic blocks. Garnets
likely grew in both block core and rind after mechanical
mixing. Fluid infiltration in the rind occurred after peak
metamorphism of the block. The source of this fluid was likely
metasedimentary rocks within the subduction zone, as has
been proposed based on O isotope compositions of this
amphibolite-facies mélange unit.
Much of the current scientific interest in serpentinites
revolves around the production of molecular hydrogen (H2)
during serpentinization, which can serve as a source of
metabolic energy for autotrophic microbial communities, or as
the reductant for abiotic formation of organic compounds.
While it has been known for some time that fluids generated
during serpentinization can be highly reducing and enriched in
H2, the processes responsible for producing these conditions
remain poorly understood. Serpentinization of ultramafic
rocks is commonly portrayed by the simple generalized
reaction: olivine + water ) serpentine + brucite + magnetite +
H2, where production of H2 occurs as a result of oxidation of
ferrous Fe [FeO] from the mineral comp-onents of the original
rock (olivine and pyroxene) to ferric Fe [FeO1.5] in the
reaction products, especially magnetite. However, petrologic
studies and laboratory experiments make it increasingly
evident that the process is much more complex than this
simple expression would indicate. For instance, rather than
going directly into magnetite, Fe from the reactant minerals is
partitioned among all solid products including serpentine and
brucite, so that the relative distribution and oxidation state of
Fe among these minerals determines the amount of H2
generated. Petrologic, lab-oratory, and theoretical studies
indicate that the proportions and oxidation state of Fe in the
product minerals is highly variable, and appears to be
dependent on a number of factors including temperature, bulk
rock composition, extent of reaction, and ‘openess’ of the
system. To complicate matters further, the Fe components of
serpentine and brucite may become unstable as the reaction
progresses, so that Fe-rich minerals formed during the initial
stages of serpentinization may decompose over time in favor
of more Fe-poor compositions and magnetite. We will present
results from ongoing laboratory experiments and modeling
studies that are an attempt to unravel the sequence of reactions
controlling Fe distribution and H2 formation during
serpentinization, and their dependence on reaction conditions.
1
Mineralogical Magazine
1
www.minersoc.org
1438
Goldschmidt Conference Abstracts
The future of marine calcifiers in a
high CO2 world: Boron isotope
systematics of pH up-regulation
M.T. MCCULLOCH1,2, J.A. TROTTER1, J. FALTER1,2
3
AND P. MONTAGNA
The University of Western Australia Oceans Institute and
School of Earth and Environment, Western Australia
2
ARC Centre of Excellence in Coral Reef Studies, UWA
3
Laboratoire des Sciences du Climat et de l’Environnement,
Av. de la Terrasse, 91198, Gif-sur-Yvette, France
1
Rising atmospheric CO2 is not only causing global
warming, but also lowering the oceans pH and hence
carbonate ion concentration upon which many marine
organisms depend to calcify their skeletons. Declining
calcification rates combined with an increased frequency of
coral bleaching from unusually high seawater temperatures
has the potential to cause major disruption to marine
ecosystems. Which marine calcifiers can sustain skeletal
development as pCO2 increases is however highly uncertain.
Here we present new boron isotopic constraints on the degree
of physiological control of the pH of the calcifying medium.
Biological up-regulation of pH is linked to abiotic
calcification rates using the inorganic kinetics of carbonate
precipitation.
Boron isotope systematics of aragonitic corals show a
species dependent ability to up-regulate the pH at their site of
calcification, with changes in internal pH being approximately
one-half of those in ambient seawater [1]. This pH buffering
capacity is present in both non-symbiont and symbiont bearing
aragonitic corals and serves to raise the saturation state of the
calcifying fluid, thereby increasing their potential rate of
calcification. The ability of biogenic calcifiers to raise the
internal saturation state via pH up-regulation is not however
ubiquitous, being absent for example in many key species of
calcitic foraminifera. Ocean acidification and global warming
are thus likely to cause a major bi-polar shift in the abundance
and distribution of marine calcifiers. Those that lack internal
pH regulation will continue to undergo rapid declines, while in
cold-water corals enhanced rates of aragonite precipitation
from pH elevation and rising temperatures has the potential to
counter the effects of decreasing seawater pH. However the
ability of tropical corals to maintain calcification rates by pH
up-regulation will mainly depend on their capacity to adapt to
thermal stress caused by rapid increases in ocean
temperatures.
Interfaces and exchange coupling
S.A. MCENROE1, P. ROBINSON1, K. FABIAN1,
R.J. HARRISON2, N. MIYAJIMA3 AND F. LANGENHORST3
Geological Survey of Norway, Trondheim 7041 Norway
(*correspondence, [email protected])
2
Cambridge University, Cambridge, UK
3
BGI, Universitaet Bayreuth Bayreuth Germany
1
Natural oxides in the ilmenite-hematite system are now
known to have contact layers [1] at the interface between the
two phases. Contact layers, reduce charge imbalance at
interfaces [2] and result in magnetic properties that are
different from the bulk host or lamellae. Magnetic coupling
across interfaces provide a mechanism for the stability of
extremely small lamellae. These samples with lamellae < 1nm
thick show exchange bias with shifted hysteresis loops more
than 13, 000 Oe. This shift is the largest that has ever been
measured in any material, natural or synthetic.
Figure 1: Shifted hystereis loop measured at 5 K. [3]
Combined TEM analyses and images with lowtemperature magnetic studies are powerful tools to describe
the chemical, structural and electronic nature of the interfaces.
To date these are the smallest stable magnets ever known.
There is wide interest in under-standing these natural samples
and their interfaces, which may well provide blueprints for
future technological designs.
[1] Robinson et al.(2002) Nature 418, 517–520. [2] Robinson
et al.(2006) Am Min. 91, 67–72. [3] McEnroe et al.(2007)
Nature Nanotechnology 2, 631–634.
[1] Trotter et al. (2011) Earth Planet Sci Lett. 303, 163-173.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Simulations of multicomponent
aerosol processes on the regional
scale
Monogenetic, but not monotonous:
Basaltic eruptions in the Auckland
Volcanic Field, New Zealand
G. MCFIGGANS*, S.R. UTEMBE, D. LOWE,
S. ARCHER-NICHOLLS AND D.O. TOPPING
Centre for Atmospheric Science, SEAES, The University of
Manchester, Oxford Road, Manchester, M13 9PL, UK
(*corresponence: [email protected])
Organic material is a significant and variable component
of tropospheric aerosol, accounting for between 10 and 90 %
of fine particle mass. Owing to its complexity, large-scale
models must represent the organic fraction and its interactions
with inorganic aerosol components using highly simplified
methods. Bottom-up representations usually underestimate
organic particulate mass and more simplified bottom-up
treatments may be expected to perform even more poorly. It is
difficult to evaluate the reasons for such behaviour, in part
because of the lack of traceability of the representation to
more complex and realistic mechanistic approaches.
In this work, we present the coupling of the reduced
Common Representative Intermediates (CRIv2-R5) scheme
[1] describing tropospheric degradation of methane and 22
emitted non-methane hydrocarbons and oxygenated volatile
organic compounds (comprising 220 species and 609
reactions), and traceable to the Master Chemical Mechanism
(v3.1), to a sectional aerosol microphysics representation
within the WRF-Chem model to enable prediction of the
regional transformation of multicomponent aerosol in the
oxidising atmosphere. The aerosol treatment uses the hyprid
Partial Derivative Fitted Taylor Expansion (PD-FiTE) [2]
coupled to the MTEM inorganic reprentation in WRF-Chem
to provide computationally efficient calculation of the
multicomponent gas / liquid equilibria in the particles. The
model can be used to investigate the regional evolution of
aerosol in the moist atmosphere and the organic contribution
to aerosol mass predicted by a mechanism traceable to a more
realistic representation of tropospheric VOC oxidation.
We will present results of the first simulations
investigating the formation and transformation of tropospheric
aerosols in the UK under a range of changing emission
profiles and oxidant conditions.
[1] Watson, L. Shallcross, D. E. Utembe, S. R. & Jenkin, M.
E. (2008) Atmos. Environ. 42, 7196–7204. [2] Topping, D.
Lowe, D. & McFiggans, G. (2009) J. Geophys. Res. 114, doi:
10.1029/2008JD010099.
Mineralogical Magazine
1439
L.E. MCGEE1*, I.E.M. SMITH1, M.-A. MILLET2,
C. BEIER3,4, J.M. LINDSAY1 AND H. HANDLEY3
School of Environment, Auckland University, Private Bag
92019, Auckland 1142, NZ
(*correspondence: [email protected])
2
SGEES, Victoria University, PO Box 600, Wellington, NZ
3
GEMOC, Maquarie University, Sydney, Australia
4
Now at Universität Erlangen-Nürnberg, Germany
1
How melts are extracted from their mantle sources and
what happens to them en route to the surface are fundamental
questions in the workings of basaltic volcanic fields. The wellsampled Auckland Volcanic Field (AVF) – an intraplate
volcanic system in northern New Zealand – offers excellent
opportunities to build up a more detailed picture of the
plumbing systems feeding such fields. Here we present major
and trace element data along with new Sr-Nd-Pb and U-series
isotopic data, in order to investigate the processes involved in
the large chemical heterogeneity seen in the AVF.
Detailed sampling has shown that individual trends for
each centre can be explained by either high-pressure
clinopyroxene or shallow olivine fractionation. Near-primary
magmas show a range in degrees of partial melting from ~5%
down to <0.5% in the smallest centres. Trace element ratios
and high (230Th/232Th) ratios (1.16-1.33) show melts are
primarily formed within the garnet stability zone and involve
two mantle sources: a FOZO-like source and a source
displaying more radiogenic Pb isotope ratios. Mixing between
these 2 end-members is seen at both the single volcano and the
field-wide scale.
U-series isotopic data for the two most chemically extreme
centres, both of which erupted twice, are used to model subtle
changes in magma dynamics. Both volcanoes follow the same
trend of eruption of an early, less primitive, smaller-volume
magma with a higher 230Th-excess, then a more voluminous,
more primitive magma with a lower 230Th-excess. Parameters
including melting and upwelling rates, conduit lengths and
porosities are modelled and found to be within the range of
other intraplate volcanic fields, yet show considerable
variation between AVF eruptions. Together with the lack of
any spatial or temporal trend in the chemistry of the field,
these results suggest that melt batches evolve in isolation,
being subject to differing processes and are able to move at
variable speeds and through variable porosities in the mantle,
resulting in dispersed plumbing systems for such fields and an
erratic pattern of eruptions.
www.minersoc.org
1440
Goldschmidt Conference Abstracts
Unusual U-REE deposits at Mt Isa,
Australia and potential links to
mid-crustal anorogenic granites
M. MCGLOIN1*, A.G. TOMKINS1 AND C.M. MACRAE2
School of Geosciences, Monash Univ, VIC, 3800, Australia
(*correspondence: [email protected])
2
Microbeam Laboratory, Minerals Down Under Flagship,
CSIRO, Clayton, VIC, 3168, Australia
Impact of biotic and abiotic factors
on the mobilization of heavy metals in
Al-Ghadir river sediments (Lebanon)
AMALE MCHEIK1, MOHAMAD FAKIH2,
NOUREDDINE BOUSSERRHINE1, JOUMANA TOUFAILY2,
VANESSA ALPHONSE1, HIBA NOUREDDINE2
1
AND EVELYNE GARNIER-ZARLI
1
The unusual Uranium-Rare Earth Element (U-REE)
deposits of Mount Isa, Queensland, associated with immobile
element enrichment (Y, Zr, Nb, LREE, locally Ti) show a
significant spatial relationship to radiometrically anomalous
intrusive phases of the mid-crustal Sybella Granite Batholith.
The high K and U radiometric anomalies in recent phases of
the Sybella Batholith suggest a possible link with the U-REE
deposits. Geochemical results for the most anomalous Sybella
microgranite phase, indicates enrichment in several
incompatible and high field strength elements, including
elevated mean LREE content (189ppm Zr, 26ppm Y, 44ppm
La and 90ppm Ce).
In the largest U-REE deposit, Valhalla, LREE enrichment
(%500ppm) is well correlated with the highest U (%3.2wt%
U3O8), associated with brannerite and uraniferous zircon [1].
The textural association of fluoroapatite surrounding
brannerite [2, 1] suggests involvement of F in controlling U,
REE and Zr mobility. The Sybella microgranite phase has
geochemical characteristics typical of anorogenic granites [3],
which are associated with U-REE mineralisation at other
localities worldwide. Previous geochronological work on the
Sybella microgranite gives ambiguous emplacement age
constraints, allowing the possibility of a syn-Isan intrusion
significantly later than the main intrusive Sybella phase (ca.
1670Ma [4]), possibly around 1555-1510Ma [1].
Our geochemical results, combined with a younger
microgranite age, would support a genetic association with the
~1530Ma U-REE deposits, and more geochronological work
is in progress to further test this possibility. Given that
magmatic fractionation promotes enrichment of the
incompatible elements seen at Valhalla, and that these
elements are generally immobile in typical metamorphic
fluids, we suggest that this unusual style of mineralisation
most likely has a magmatic-hydrothermal origin.
[1] Polito et al. (2009) Min Dep 44, 11–40. [2] Gregory et al.
(2005) Econ Geol 100, 537–546. [3] Eby (1990) Lithos 26,
115–134. [4] Page & Bell (1986) Journal Geol 94, 365–379.
Mineralogical Magazine
IBIOS – BIOEMCO, Faculty of sciences and technology,
University Paris-Est, 61 avenue de general chales de
gaulles, 94010 Creteil Cedex, France
2
Laboratory MCEMA, Faculty of Sciences (I), Lebanese
University, Hadath Beirut, Lebanon
1
Although there is no doubt about the importance of
bacterial activity on solubilisation and distribution of metal in
aquatic sediments, hydromorphic soils and ground waters very
little is known about the involvement of bacterial dissolution
in periodically anaerobic environments like that found in
dredged sediments and little is known about the processes and
environmental factor controlling this process.
Our study aims at underlining the role of autochthonous
bacteria in the biodegradation of organic matters and the
mobilization of metals (Zn, Pb, Co, Cr, Cd, Al, Mn and Fe)
contained in sediments in Al-Ghadir river. In order to do so,
we have follow over time the evolution of carbon metabolism
(Organic matter evolved, carbon consumption, organic acids
production) and metals release in batch reactor where the
sediments were mixed with a culture medium. The
experiments were monitored under standard anaerobic
conditions.
Under the adopted conditions, the incubated sediments
showed a significant release of organic carbon corresponding
to bacterial development.
Mineral analysis showed an important solubilisation of
iron and manganese (in reduced form) indicating the presence
of Fe and Mn-reducing bacteria in sediments. Co and Cr
solubilisation were also observed and appeared concomitant to
Fe and Mn indicating that Co and Cr are associated to Fe and
Mn in sediment. Al and Zn were associated to organic matter
while Cd and Cu were associated to organic matter and to Fe
and Mn oxides.
At the end of the incubation, the molecular techniques
showed (i) the disappearance of some bacterial strains due to
the toxicity of the released heavy metals and (ii) the growth of
new population of microorganisms tolerant to the same heavy
metals.
www.minersoc.org
Goldschmidt Conference Abstracts
Silicic acid: An experimental and
ab initio study of explicit solvation
and reaction kinetics
How and where redox-sensitive trace
metals can answer the question
productivity or ventilation
G.J. MCINTOSH*, P.J. SWEDLUND AND T. SÖHNEL
Department of Chemistry, University of Auckland, Private
Bag 92019, Auckland, New Zealand
(*correspondence: [email protected])
Ab initio quantum chemistry has become a powerful
supplement to experimental studies of gas-phase systems in
particular. However, while the application to species of
geochemical interest such as silicic acid, H4SiO4, is
achievable, it is dramatically complicated by the presence of
water. As both computer speed and the efficiency of quantum
chemical algorithms progress, it is becoming increasingly
feasible to go beyond simple continuum descriptions of the
solvent to the inclusion of explicit solute-solvent interactions.
We have recently benchmarked the effects of explicit
solvation in a theoretical study of a counter-intuitive reverse
isotope shift observed in the vibrational spectra of aqueous
H4SiO4 and D4SiO4 [1]. Upon deuteration, the antisymmetric ?
(Si-O) stretching modes shifts to higher frequencies, in
opposition to what is anticipated from reduced mass
arguments. DFT/B3LYP/6-31+G (d)-based models are unable
to describe this shift without the inclusion of explicit water
molecules. Specific hydrogen bonding interactions, present
only within an explicit solvation framework, are found to
significantly stiffen and blueshift the & (Si-O-H/D) bending
modes. In D4SiO4, these bends subsequently couple with the ?
(Si-O) modes; resonance effects blueshift the stretching modes
by a greater extent than the increased mass-induced red shift,
leading to a net reverse-isotope shift. Similarly, the positions
of & (Si-O-H/D) modes in the IR and symmetric ? (Si-O)
modes in the Raman, and peak widths and heights are also
only reproduced with the inclusion of explicit solvation
effects.
On the strength of these results, we have begun exploring
the feasibility of deriving a kinetic model of silicate
polymerization and hydrolysis almost entirely from first
principles. We present preliminary results benchmarking
transition state theory approximations and the roles of implicit
and explicit solvation in modelling the kinetics of H4SiO4
dimerization. Early results suggest that this approach may
provide a surprisingly good model of reaction kinetics and
thermodynamics in pH- and temperature-dependent systems.
J.L. MCKAY1*, T. IVANOCHKO2 AND T.F. PEDERSEN3
COAS, Oregon State University, Corvallis, OR 97330, USA
(*correspondence: [email protected])
2
EOS, University of British Columbia, Vancouver, BC, V6T
1Z4, Canada ([email protected])
3
SEOS, University of Victoria, Victoria, BC, V8W 2Y2,
Canada ([email protected])
1
The enrichment of redox-sensitive trace metals such as Re
and Mo is commonly used to infer changes in paleo redox
conditions of marine sediments. Determining why redox
conditions changed is trickier because both organic carbon
flux (e.g. export productivity) and changes in bottom water
oxygen (e.g. ventilation) can influence sedimentary redox.
Which of these factors is the dominant control can be sorted
out by analyzing Ag along with the redox-sensitive metals
noted above. Unlike these other metals, Ag does not
accumulate after sediment deposition. Rather it is scavenged
from the water column by organic particles and transported to
the sediment as part of the biogenic particle flux. Its
accumulation in sediments is therefore related to productivity.
Thus, high Ag in combination with high Re and/or Mo
suggests that high productivity is controlling sedimentary
redox while a combination of low Ag and high Re and/or Mo
suggests a lack of ventilation. Some environments, however,
don’t lend themselves well to the use of redox-sensitive trace
metals. Surface sediments from the OMZ on the Pakistan
Margin, for example, are characterized by relatively low Re
and Mo concentrations in comparison to oceanographically
similar regions off Mexico and Peru. Silver concentrations are
also anomalously low except near the base of the OMZ
indicating post-depositional oxidation and loss of Ag.
Together these trace metal data suggest that OMZ sediments
on the Pakistan Margin are at best weakly suboxic despite
their high organic carbon content and the low bottom water
oxygen values.
[1] McIntosh et al. (2011) Phys. Chem. Chem. Phys. 13,
2314–2322.
Mineralogical Magazine
1441
www.minersoc.org
1442
Goldschmidt Conference Abstracts
Integration of the intrusive and
extrusive cycles of Palaeogene
igneous activity in N.E. Ireland
C. MCKENNA1*, J.A. GAMBLE1, P.R. RENNE2,
R.M. ELLAM3, J.G. FITTON4 AND P. LYLE1
School of BEES, National University of Ireland, Cork, Rep.
of Ireland (*correspondence: [email protected])
2
Berkeley Geochronology Centre, 2455 Ridge Road, Berkeley,
CA 94709, USA ([email protected])
3
Scottish Universitites Environmental ResearchCentre, East
Kilbride G75 0QF, UK ([email protected])
4
School of GeoSciences, , University of Edinburgh, Edinburgh
EH9 3JW, UK ([email protected])
1
We compare trace element and isotopic (Sr, Nd, and Pb)
geochemical data from the mafic intrusive complex of Slieve
Gullion with new data from the thick sills (up to 100 m) at
Portrush, Carrickarede and Fair Head in N Antrim and make
comparisons to the Antrim Lava Group (ALG) flood basalts.
Slieve Gullion rocks (56.5±1.3 Ma) are characterised by
flat ~10x chondritic HREE with slight +ve Eu-anomalies and
LREE enrichment ((La/Pr)CN = ~2.5). Portrush sill rocks
(54.9±0.6 Ma) show similar flat HREE patterns, +ve Eu
anomalies and faint LREE enrichment ((La/Pr)CN >1). By way
of contrast Carrickarede and Fair Head (60.2±0.3 Ma) rocks
show convex upward REE patterns, with maximum REE
enrichment at Nd ((La/Pr)CN < 1, (Nd/Lu)CN ~ 4).
Multielement plots of incompatible elements for Slieve
Gullion and Portrush rocks display similar flat patterns for
HREE and HFSE, with distinctive +ve spikes at Pb, Sr and Rb
and –ve Nb anomalies, that strongly resemble subduction
modified melts or continental crust. The Fair Head rocks show
distinctive, smooth upwardly convex patterns.
The Lower Basalts (~60-62 Ma) of the ALG show similar
convex upwards REE patterns as the Fair Head and
Carrickarede rocks, whereas many of the younger Upper
Basalts (~59-57 Ma) resemble the younger intrusions at
Portrush and Slieve Gullion, but with flat or LREE depleted
REE patterns.
A key to understanding the evolution of the N.E. Irish
sector of the North Atlantic Igneous Province is explaining
such differences in temporally related rocks, which cannot be
rationalised solely by partial melting of a similar source. We
suggest that the LREE enrichment and Pb, Sr, Rb spikes so
distinctive of the Slieve Gullion magmas, and also hinted at in
Portrush, might derive from a lithospheric mantle component,
as the melting regime penetrates into lithospheric mantle as
extension developed across the Province.
Mineralogical Magazine
Complex Al and P zoning in pallasite
olivine: Constraints on high-T history
SEANN J. MCKIBBIN1*, HUGH ST.C. O’NEILL1,
GUILHERME MALLMANN1,2 AND ANGELA HALFPENNY1,3
Research School of Earth Sciences, Australian National
University, Canberra ACT, Australia
(*correspondence: [email protected])
([email protected])
2
Institute of Geosciences, University of São Paulo, São Paulo
SP 05508-080, Brazil ([email protected])
3
Earth Science and Resource Engineering, CSIRO, Kensington
WA, Australia ([email protected])
1
Pallasites are mixtures of olivine and Fe-Ni metal,
possibly formed near the core-mantle boundary of a
differentiated asteroid [1]. The distribution of trace elements
in pallasite olivine appears to reflect diffusion profiles [2]
although complex structure has also been reported [3]. It has
recently been shown experimentally [4] and in various natural
samples [5] that Al and P diffuse very slowly in olivine and
these elements can preserve early distributions which are
resistant to later thermal modification.
To search for evidence of the early history of pallasite
olivine, we have used Laser-Ablation Inductively-CoupledPlasma Mass-Spectrometry (LA-ICP-MS) to produce traceelement maps of olivine from two pallasites: Brahin (with
fragmental olivine) and Brenham (rounded olivine).
Heterogeneous distributions are found over scales of ~100
microns for Al and elements likely to associate with it in
coupled substitutions. P is also heterogeneously distributed but
is negatively correlated with or unrelated to Al. In Brahin,
these distributions bear no relationship to the olivine
morphology; for Brenham, Al concentrations decrease at grain
margins but the interiors have complex distributions.
Heterogeneous distributions of Al and P in pallasite
olivine provides some constraints on its residence time in a
high-T environment. Taking the diffusion parameters for Si
[6] as a proxy for the diffusion behaviour of these elements
(since they reside in the same crystallographic site), at 1650 K
(~OPX out for a fertile peridotite composition; [7]) the
characteristic timescale for diffusion over 100 microns is ~1
Ma. This represents an upper limit on the time between the
establishment of trace element systematics in olivine and
formation of pallasites by mixing with metal.
[1] Scott, E.R.D. (1977) GCA 41, 693. [2] Miyamoto, M.
(1997) JGR 102, 21613. [3] Tomiyama T. & Huss G.R. (2006)
LPSC 37, 2132. [4] Spandler C. & O’Neill H.St.C. (2010)
CM&P 159, 791. [5] Milman-Barris M. et al. (2008) CM&P
155, 739. [6] Dohmen R. et al. (2002) GRL 29, 2030.
[7] Walter M. J. (2003) in Treatise on Geochemistry 2.08,
363–394.
www.minersoc.org
Goldschmidt Conference Abstracts
Relationships between the
composition of planetary crusts and
their sedimentary records
SCOTT M. MCLENNAN
Dept. of Geosciences, SUNY at Stony Brook, Stony Brook,
NY, 11794-2100, USA ([email protected])
Planetary crusts possess variable sedimentary records in
terms of origin, size, lithology, age and composition. At one
extreme, Earth has a complex sedimentary record formed in
response to weathering, erosion, transport, deposition and
recycling. The highly dynamic terrestrial rock cycle precludes
preservation of any significant planetary regolith (eolian
deposits being the closest analog). At the other extreme,
airless bodies like the Moon, and probably Mercury, possess
classic impact-derived planetary regoliths as their only
sedimentary deposit. Mars provides the intermediate case
where a long-lived sedimentary rock record exists but the
surface is also covered widely by regolith. Controls on
planetary sedimentary records are related to (1) impact and
volcanic history, (2) presence and nature of atmospheres (i.e.
climate), (3) occurrence, composition and physical state of
near-surface volatiles, and (4) presence and nature of crustal
tectonics, crustal evolution, and so forth. In turn, the
composition of planetary sediments reflects their crustal
sources in complex, but generally understandable ways. The
terrestrial sedimentary record is lithologically differentiated
(shales, sands, carbonates, evaporites) due mainly to large
bodies of water. Nevertheless, terrestrial sediments reflect
widespread sources and accordingly have long been used to
estimate upper crustal composition and to trace crustal
evolution. For impact-derived lunar regolith, absence of water
and air restricts reworking or transport on any significant scale
after initial deposition. Disruption and mixing take place but
by impact gardening that operates on local scales and largely
in a vertical sense. The result is that lunar regoliths do not
sample widespread regions and so are compositionally
variable, matching the crust in the vicinity of where they form.
Martian sedimentary rocks and regolith formed by a wider
array of processes than did lunar regolith, including impact,
volcanic, glacial, eolian and subaqueous processes, and are far
more complex mineralogically. On the other hand, much less
lithological differentiation takes place than is seen on Earth.
Sedimentary mixing processes at the surface (e.g. eolian,
glacial, impact gardening) were of sufficient scale to minimize
variations in regolith composition. Although local geological
influences are observed, Martian regolith is of broadly
uniform composition, reflecting the average upper crust even
for the major elements.
Mineralogical Magazine
1443
A 4-dimemsional landscape
geochemical framework for the
remote arid landscapes of Australia's
Musgrave Province
S.M. MCLENNAN1* AND S.M. HILL2
The University of Adelaide, Adelaide, 5005, Australia
(*correspondence: [email protected])
2
The University of Adelaide, Adelaide, 5005, Australia
([email protected])
1
This study integrates geochemical and biogeochemical
datasets generated from the remote arid landscape of the
Musgrave Province in Central Australia. It demonstrates the
inter-relationships between the chemistry of the region and its
landscape evolution. Many previous geochemical studies of
the arid landscapes of Australia have tended to focus on a
single system or sampling medium. Where datasets for several
media are combined and compared they have tended to be
considered within the context of a featureless ‘space’ rather
than their landscape setting. In this study bedrock
geochemical,
regolith
geochemical,
groundwater
hydrogeochemical and plant biogeochemical systems are
sampled, chemically characterised and compared based on
their landscape setting. This study utilises the importance of
the evolution of regolith materials that have evolved within the
landscape's history as the context.
An initial focus has centred on the Mt Caroline ultra-mafic
intrusion, which is considered prospective for Ni-Cu sulphide
deposits. Variably think sedimentary cover (10s to 100s m),
Aboriginal land access restrictions, and a lack of tracks and
roads through the region have limited the development of
previous landscape geochemical models. Access to some
exploration tenements, however, has allowed the development
of a geochemical sampling program incorporating regolith
materials, biota (especially Triodia basedowii), and
groundwater. Given the extent and variation in thickness of
sedimentary cover in the area, however, plotting and
comparing these datasets in two dimensions is an oversimplification of the dispersion processes at play in this
system. This project optimises the presentation of these
datasets to show differences between the results and
similarities between anomalies to assist in further developing
future exploration programs. The study proposes an effective
means of presenting data that incorporates the geochemistry
across the landscape in two dimensions but also the role of
landforms and varying lithologies in surface expression of
concealed mineral deposits.
www.minersoc.org
1444
Goldschmidt Conference Abstracts
The origin of carbonate globules in
silicate melts: Solids or liquids?
S.C. MCMAHON*, D.K. BAILEY, M.J. WALTER
AND L. CARICCHI
Department of Earth Sciences, University of Bristol, BS8 1RJ
(*correspondence: [email protected])
Carbonate globules found in mantle xenoliths, as
inclusions in mantle minerals and in juvenile silicate melt
lapilli are possible examples of primitive carbonatitic melts
from the mantle [1]. Here we present findings from carbonate
globules from Finca La Nava, a matrix-supported carbonatite
tuff in the Calatrava Volcanic Province in central Spain; an
alkaline mafic-ultramafic province comprising over 250
monogenetic cones and vents [1]. Carbonate globules are
prolific within silicate melt lapilli. Silicate melts of at least
two different compositions, melilitite and kamafugite, have
been discovered within this one outcrop.
The origin of the carbonate globules within melt lapilli is
debatable. Globule textures including curved menisci against
silicate melt, budding, and coalescing of the globules, are
compelling evidence for liquid immiscibility. However, recent
experimental results suggest that similarly-shaped globules
formed as solid calcite crystals in equilibrium with silicate
melt [2]. Many, but not all, globule interiors in the Calatrava
lapilli are apparently nearly phase-pure calcium carbonate
with minor Mg, but Si, Al, and Na are virtually absent. Yet
experiments show that carbonatitic melts equilibrated with
mantle silicates or silicate melts can dissolve significant
amounts of these elements, suggesting that the globules may
have originated as solid calcite, as in the experiments. So did
these carbonate globules originate as solids or liquids?
The ‘pure’ globules are in fact both compositionally and
texturally heterogeneous on a micron scale. Initial findings
made on the basis of sub-micron elemental mapping using a
FEG-SEM demonstrate that considerable quantities of
additional components of Si and Al, amongst other major
elements, appear to have been exsolved and segregated to the
globule rims during crystallisation. Such a mechanism may
explain the observed ‘pure’ calcium carbonate composition of
many globule interiors, and supports an immiscible liquid
model for carbonatite tuff genesis in Calatrava.
[1] Bailey et al. (2005). Mineral Mag 69, 907-915. [2]
Brooker & Kjarsgaard (2010) Journal of Petrology doi:
10.1093/petrology/egq081
Mineralogical Magazine
Timing and duration of Heinrich
events in the North Atlantic
JERRY F. MCMANUS
Lamont-Doherty Earth Observatory of Columbia University,
Palisades, NY 10964, USA
(*correspondence: [email protected])
The repeated iceberg discharges into the North Atlantic
during the Pleistocene, known as Heinrich events, are widely
believed to have influenced the global climate. Their
millennial pacing, abrupt occurrence, and widespread impact
make them important targets for understanding the rates of
climate change. Efforts to date the sedimentary layers
associated with these events have achieved some success,
particularly for the few events within the range of 14C
methods. Similarly, the duration of the youngest events has
been estimated by foraminifera 14C and sedimentary 230Thxs.
Beyond these most recent events, the Heinrich layers of icerafted sediments have typically been dated by correlation to
other sedimentary archives with independent chronologies,
such as ice cores and speleothems. In this study, two different
approaches to 230Thxs profiling have been utilized to explore
directly the absolute timing and duration of each of the
Heinrich events that occurred during the last large climate
cycle of the Pleistocene. Both approaches incorporate new
sedimentary data generated by ICP-MS at locations where
initial results were produced by alpha counting. Heinrich event
H11 is shown to occur within the penultimate deglaciation
identified in foraminifera "18O. Using Thxs profiling in a core
from the Caribbean sea with an approximately constant
accumulation rate, an age estimate of 133 ky is derived for the
timing of H11, following Broecker and van Donk [1]. In core
V28-82 from the subpolar North Atlantic, with a variable
accumulation rate, the inventory of sedimentary 230Th is
shown to be in balance with the overlying seawater production
of 230Th, and Sackett’s method [2] to quantifying the passage
of time can be applied to estimate both the absolute age and
duration of each of the Heinrich events. The results support
previous estimates that the sedimentary layers associated with
the events were deposited rapidly over the course of centuries,
not millennia.
[1] Broecker, W. S. & van Donk, J. (1970) Insolation changes,
ice volumes & the O18 record in deep-sea cores. Reviews of
Geophysics & Space Physics 8, 169–198. [2] Sackett, W. M.
(1965) Deposition rates by the protactinium method. In
"Symposium Volume." (D. R. Schink, & J. T. Corless, Eds.)
pp. 29–40. URI.
www.minersoc.org
Goldschmidt Conference Abstracts
Maximising precision and accuracy
in laser quadrupole ICPMS U-Pb
geochronology
SEBASTIEN MEFFRE, LEONID DANYUSHEVSKY,
MARCEL GUILLONG AND SARAH GILBERT
School of Earth Sciences & Australian Research Council
Centre for Excellence in Ore Deposit Studies, University
of Tasmania, Australia, ([email protected])
Laser mass spectrometry is widely used to determine the
age of rocks throughout the earth science. However, analytical
problems related to ablation cells, standards, mass
spectrometers and calculations have meant that it is difficult to
fully characterise precision and accuracy of the technique.
Experiments performed at the University of Tasmania
over the last 10 years have shown that the following
parameters affect the precision and accuracy of measurements:
1) homogeneity of the signal in the ablation cell, 2) type,
number and position of standards analysed within the
analytical sequence 3) accuracy dead time corrections 4)
amount of instrumental drift, 5) contamination during cleaning
and polishing 6) calculation method used 7) tuning parameters
and signal intensity 8) harmonic interference between the laser
and the mass spectrometer (spectral skew).
The contribution of each of these parameters to the
uncertainty of the final measurements is complex and changes
with age and uranium concentration of the crystals. For
example young and low U zircons (those which have
accumulated <0.2 ppm radiogenic Pb) must be carefully
cleaned and calculated using the ‘ratio of the mean’ rather
than the ‘mean of the ratio’ method but are relatively
insensitive to the position and homogeneity of the standards,
dead time corrections, harmonic interferences and
instrumental drift compared to older high U zircons.
Mineralogical Magazine
1445
Mechanical instabilities induced by
sulfate adsorption
M. MEGAWATI1*, A. HIORTH2 AND M.V. MADLAND3
University of Stavanger, 4036 Norway
(*correspondence: [email protected])
2
International Research Institute Stavanger, 4068 Norway
([email protected])
3
University of Stavanger, 4036 Norway
([email protected])
1
We present experimental data and analytical calculations
which demonstrate the effect of negative surface charge
caused by sulfate adsorption in high porosity chalks. Rock
mechanical tests on three high-porosity outcrop chalks flooded
with Na2SO4 at 130 0C show a significant decrease in the yield
strength and in the bulk modulus compared to that of NaCl
flooding. At 50 0C, however, no significant difference in the
mechanical strength between cores exposed to Na2SO4 and
NaCl is observed. Relative to that of the distilled water
flooding (i.e. no sulfate present) a decreasing strength of 2040% in the yield and 10-70% in the bulk modulus are
correlated well with the increasing sulfate concentration in the
pore water at higher temperature (130 °C). In addition
standard creep tests at constant stress level of 10.7 and 18.9
MPa show similarly high creep rate along the creep stages. We
measured sulfate adsorption of 0.2 µmol/m2 and 0.5-1
µmol/m2 at 50 °C and 130 °C, respectively, while dissolution
was found to be low (below 0.4 mM Ca2+ produced after 14
PV’s flooded). The sulfate adsorption process is interpreted by
using surface complexation model together with GouyChapman theory to describe the electrical double layer. The
analytical calculations give fairly good agreement with the
measured sulfate adsorption and comparable with -potential
measurement data respectively. The reduced mechanical
strength is related to the sulfate adsorption which leads to a
negative (pH dependent) surface charge. We suggest that the
interaction between charged surfaces specifically in the weak
overlaps of electrical double layer gives rise to the total
disjoining pressure, which acts as normal forces in the grains
vicinity, and it counteracts the shear forces during the failure
mechanism. Increasing magnitude of the disjoining pressure
when chalk cores are exposed to different Na2SO4
concentration at 130 °C correlate well with the reduced
strength from the mechanical test results. The correlation
remarkably reproduces the same trend as observed in the yield
strength and bulk modulus as a function of Na2SO4
concentrations.
!
www.minersoc.org
Goldschmidt Conference Abstracts
1446
The effect of sulfate adsorption on the
cation exchange capacity of high
porosity chalks
M. MEGAWATI1, A. HIORTH2* AND M.V. MADLAND3
University of Stavanger, 4036 Norway
([email protected])
2
International Research Institute Stavanger, 4068 Norway
(*correspondence: [email protected])
3
University of Stavanger, 4036 Norway
([email protected])
The structural determinants of silicon
fractionation properties of silicate
minerals: A first-principles density
functional study
M. MÉHEUT1* AND E.A. SCHAUBLE2
1
GET, Université Paul Sabatier, Toulouse, France
(*correspondence: [email protected])
2
ESS Dept., UCLA, Los Angeles, USA
1
Understanding the process of sulfate adsorption onto the
chalk surfaces is important as it has been associated with
wettability change [1, 3] and it was also shown to impact the
mechanical stability of high porosity chalks [2]. In this paper
we determine the cation exchange capacity (CEC) from core
floods with and without sulfate present in the pore fluids. We
model the sulphate adsorption in terms of interaction with
positive Ca sites at the calcite mineral surface [1]; resulting in
a net negative surface charge. The cation exchange is believed
to take place in the diffusive counter ion layer. Our
experimental results remarkably show that CEC increases with
almost a factor of 2 upon adsorption of sulfate and the
retardation of Na+/K+ front as well increases significantly
(see Table 1). The enhanced CEC due to sulfate adsorption
could thus contribute to an improved understanding of the
enhanced compaction as observed during rock mechanical
tests.
Chalk
T
Sulfate
ads.
C
µmol/m2
0
Liege
S.Klint
50
90
130
50
90
130
0.36
0.80
1.04
0.49
0.81
1.16
With adsorbed
SO4
Retard.
CEC
of
Na+/K+
PV
mEq/L
0.10
0.11
0.10
0.02
0.02
0.02
2.18
2.05
1.94
1.14
1.12
1.12
Without
adsorbed SO4
CEC
(Exp.)
Retard.
of Na+
mEq/L
PV
0.06
0.05
0.06
0.01
0.01
0.01
1.35
1.28
1.28
1.03
1.04
1.05
Table 1: Increasing trend in the CEC upon adsorption of
sulfate.
[1] Hiorth et al. (2010) TIPM 10.1007/s11242-010-9543-6.
[2] Korsnes et al. (2008) Journal Pet.Sci.Eng 60, 183–193.
[3] Strand et al. (2001) Journal Pet. Sci.Eng 52, 187–197.
!
Mineralogical Magazine
Ab initio methods based on density functional theory have
proven to be successful in reproducing the physical and
chemical properties of complex systems. Within this
framework, we have recently developed a methodology to
predict equilibrium fractionation factors as a function of
temperature (1). We use PBE functionals, combined with the
use of pseudopotentials and planewave basis sets. Our
previous work focused on the effect of the polymerization of
the silicate network on Si-isotope fractionation (2), which had
previously been predicted to be a determining factor. Our
work does not confirm this assumption. To investigate the
origin of this fractionation, we studied minerals with identical
polymerization structures such as talc, pyrophyllite,
muscovite, phlogopite or clinochlore. In the case of muscovite
and phlogopite, the calculated quartz-mineral fractionations
are in qualitative agreement with natural estimates. In this
family of silicates, a strong correlation can be shown between
the mineral-quartz fractionation of silicon and cationic
content. Together with the simple shape of the fractionation
laws, this permits to propose the following approximate law,
valid for any temperature T (in K):
ln+(phyllo.,qtz,Si,T)=a(T)*[Mg(o)]+b(T)*([Al(o)]+2*[Al(t)]),
where [Mg(o)], [Al(o)] and [Al(t)] represent the content of
octahedric magnesium, aluminium and tetrahedric aluminium
relative to 4 tetrahedral units, and a(T)=-12.834x2+14.39x3;
b(T)=-5.040x2+4.20x3, with x=102/T
This relationship can apparently be extrapolated to
fractionation properties of tectosilicates (quartz and albite) and
inosilicates (enstatite) but fails to reproduce the properties of
forsterite. To better understand the limits of this apparently
general correlation, we plan to present calculations for several
chain silicates (diopside, wollastonite, jadeite), and potentially
nesosilicates (fayalite, zircon, garnet). We will also focus on
the interpretation of this relationship in terms of cationic force
field effects.
[1] Meheut et al. (2007) GCA 71, 3170–3181. [2] Meheut et
al. (2009) Chem. Geol. 258, 28.
www.minersoc.org
Goldschmidt Conference Abstracts
Petrogenesis and geochemistry of the
Dajing Cu-Sn-Pb-Zn-Ag Ore Deposit
in Chifeng, Inner Mongolia
1447
Ab initio molecular dynamics
simulation of copper(I) complexation
in chloride/sulfide fluids
WEI MEI1, XINBIAO LÜ1,2*, ZHILONG AI1,
RANKUN TANG1 AND ZHI LIU1
YUAN MEI1,2,3, DAVID M SHERMAN2, JOËL BRUGGER1
3
AND WEIHUA LIU
1
Faculty of Earth Resources, China University of Geosciences,
Wuhan 430074, China ([email protected])
(*correspondence: [email protected])
2
State Key Laboratory of Geological Processes and Mineral
Resources, China University of Geosciences, Wuhan
430074, China
1
The Dajing deposit is the largest tin deposit at the north of
North China, which is a fissure-filling hydrothermal ore
deposit located at the south of Daxinggan Mountain with Sn,
Cu, Pb, Zn, Ag mineralisation. The deposit is controlled by
multistage of fracture systems, mainly including NE striking
sinistral compresso-shear fractures, a suite of SN striking
compresso-shear fractures, and NW striking tenso-shear
fractures (with ore veins mainly filling in this group of
fractures). The widely outcropped magmatic rocks in the ore
district are sub-volcanic rocks. They intruded into the Upper
Permian Linxi Group that was formed in the inshore lake
basins environment. The sub-volcanic dykes are divided into
four main types: aphanophyre, acidic to intermediate rocks
(dacite porphyry, rhyolite porphyry and granite porphyry),
intermediate to basic rocks (andesitic porphyrite, diabasic
porphyrite and basaltic prophyrite) and lamprohpyre, which
scattered in the ore district. However, the subvolcanic rocks
are dominated by acidic rocks in the central part, and
intermdiate to basic rocks in the eastern part. K-Ar bulk
isotopic age of the dykes ranges from 155.3 to 177.2 Ma. Wall
rock alterations are weak silicification, carbonatization,
chloritization and sericitization. They occur on both sides of
ore veins.
The acidic rocks in the central are a suit of high-K calcalkaline dacite with high content of Cu and Sn, while the basic
rocks in the eastern are a suit of shoshonitic basalt to basalticandesite rocks with high content of Pb and Zn. All the rocks
are characterized by enriched LILE and LREE, but acidic
rocks have lower REE content with intermediate negative Eu
anomaly (#Eu=0.56-0.58). All the rocks originated from the
same mantle source. They underwent high degree of
differentiation and evolution when entered into the secondary
magma chamber.
Chloride and hydrosulfide are the primary ligands
believed to control the transport of copper in hydrothermal
fluids. Recent studies of Cu complexation in hydrothermal Cl-,
HS- solutions have been done using X-ray Absorption
Spectroscopy (XAS). However, coordination numbers have a
large uncertainty and are strongly correlated with DebyeWaller factors; moreover, it is very difficult to distinguish
between chloride and sulfur ligands. Ab initio molecular
dynamics simulations based on density functional theory
enable us to interpret EXAFS results and, potentially, predict
stability constants of metal complexes.
In this study, we investigated the species of copper(I)
complexes via ab initio Car-Parrinello Molecular Dynamics
simulations for copper(I) solutions with different
hydrosulfide/chloride ratios at 500bar and 600K. Calculations
were done using Vanderbilt ultrasoft pseudopotentials and the
PBE exchange-correlation functional.
In the absence of Cl-ligands, copper forms a Cu(HS)2complex with a Cu-S bond length of 2.17 Å (vs. an expt. value
of 2.15 Å); moreover, the S-Cu-S bond angle is ~162°, in
excellent agreement with experiment (150-160°). In the
presence of excess chloride, however, we find that Cu forms
previously unknown Cu(HS)Cl- and (minor) CuCl2(HS)-2
complexes. Such complexes would be difficult to resolve from
CuCl2- or Cu(HS)2- using EXAFS. We also explored the
complexation of Cu in a low density (0.29 g/cm3), high T
(1273K) fluid (vapour). Here, we find that Cu forms Cu(HS)2(not the neutral CuHS, as expected). We tentatively suggest
that charged complexes may be significant in high
temperature, low density fluids.
Ultimately, we hope to predict stability constants of metal
complexes. To this end, we are testing metadynamics and
thermodynamic integration with respect to metal-ligand
distances or coordination numbers. Using these techniques, we
estimate the free energy difference between CuCl2- + HS- and
CuCl(HS)- + Cl- to be ~40 KJ/mol.
This work is founded by 305 Project of State Science and
Technology Support Program (Grant No. 2007BAB25B04).
Mineralogical Magazine
School of Earth and Environmental Sciences, The University
of Adelaide, Adelaide, SA 5000, Australia
2
Department of Earth Sciences, University of Bristol, Bristol,
BS8 1RJ, UK
3
CSIRO Earth Science and Resource Engineering, Clayton,
VIC 3168, Australia
www.minersoc.org
Goldschmidt Conference Abstracts
1448
NanoSIMS: New results of relevance
to biomineralization and biology
ANDERS MEIBOM
Quantification of environmental
proxy precision
ANDERS MEIBOM AND CHRISTOPHE KOPP
Muséum d'Histoire Naturelle, Paris, France
Muséum d'Histoire Naturelle, Paris, France
The NanoSIMS is a relatively new type of ion microprobe
that can deliver a primary beam of Cs+ or O- to a sample
surface, focused to a minimum spot size of ~50 nanometers
and ~150 nanometers, respectively. (On non-conducting
materials, bombardment with Cs+ causes strong charging
effects. Such positive charge build-ups are compensated by
electrons, which can be delivered to the sample surface by an
electron gun.) Secondary ions sputtered from the sample
surface and charged opposite to the primary beam are
transferred with high transmission to a high mass-resolution,
multi-collection mass-spectrometer that allows simultaneous
collection of five or seven (depending on the model) different
isotopes in electron multipliers and/or Faraday cups. This
means that five (or seven) different images can be
simultaneously recorded from the same sputtered volume.
This capability can be used to create images or maps of
elemental and isotopic variation within a sample. Such images
can be generated from the lightest elements, such as H (D/H
ratios), C (13C/12C ratios), N (15N/14N ratios), O (17O/16O and
18
O/16O ratios) and S (e.g. 34S/32S ratios) to the heaviest
elements in the periodic table, including uranium.
Ion images of the sample surface are created by a precisely
controlled raster of the primary beam across the sample
surface. The NanoSIMS is therefore a powerful analytical
instrument in conjunction with biological labeling
experiments, where high spatial resolution is required and high
analytical precision is not a requirement. Importantly, it is
possible to do high quality NanoSIMS imaging even on very
thin sections prepared for TEM analysis.
This presentation will include examples of the
combination between dynamic isotopic labeling experiments,
SEM, TEM, STXM, and NanoSIMS imaging to study skeletal
formation dynamics and single-cell-level ammonium
assimilation in reef-building corals.
The extent and causes of recent environmental variations
represent a vitally important problem for scientists, lawmakers
and society in general. Essential to the ongoing scientific
debate is the development of proxies that can reconstruct
environmental change on both short (10-1000 years) and long
(i.e. geologic) timescales. However, for every such proxy, a
fundamental question exists that is rarely addressed: To what
precision can the proxy reconstruct environmental variation?
Only by answering this question quantitatively is it possible to
decide if a given proxy is precise enough to be applicable and
useful.
Here, we illustrate and discuss the vital effects that plague
the major proxies for e.g. ocean sea-surface temperature. This
will be based on recently acquired micro-analytical data, in
particular with the NanoSIMS ion microprobe. Subsequently,
the precision of linear environmental proxies is quantified
with a general and easily applicable method. The precision of
a selection of existing proxies is evaluated against the
requirements of e.g. anthropogenic global warming.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Automated characterization of
Eyjafjallajökull ash cloud particles
A record of Paleoproterozoic sulfur
cycling from ~2 Ga Zaonega
Formation, NW Russia
M.F. MEIER1*, K. WEBER2, A. VOGEL2, C. FISCHER2
1,3
AND B. GROBÉTY
Univ. of Fribourg, Dept. of Geosciences, 1700 Fribourg,
Switzerland (*correspondence: [email protected])
2
Univ. of Applied Science, 40474 Düsseldorf, Germany
3
Univ. of Fribourg, FRIMAT, 1700 Fribourg, Switzerland
D. MEISTER1*, V.A. MELEZHIK2,3, A. LEPLAND2
1
AND H. STRAUSS
1
The Eyjafjallajökull (EFJ) ash cloud crisis caused an
airspace closure over Europe in April 2010 and had an
important impact on economy. During this crisis the
Dusseldorf University of Applied Sciences performed several
measurment flights over north-western Germany with a light
aircraft equipped among other with an optical particle counter
(OPC) [1]. The primary goal of the airborne campaign (two
flights F1 and F2, 18th May, different routes) was to compare
the model calculation of the Volcanic Ash Advisory Center
(VAAC) with in situ observation. The aim of this work is to
present results of computer controlled scanning electron
microscopy (CCSEM) coupled with engergy dispersive X-ray
spectroscopy (EDX) applied on particles sampled on PTFE
filters obtained from the OPC outlet. CCSEM/EDX generates
morpho-chemical data of over 1000 particles in a few hours.
Many of the particles sampled during F1 were silicate
dominated particles with compositions similar to the ones
obtained from ash particles sampled on Iceland during and
after the eruption of EFJ. Augitic clinopyroxenes could be
identified morphologically. X-ray diffraction analyses of the
eruption products confirm the presence of augite phenocryst.
This points to the conclusion that the aerosol sampled during
F1 was indeed volcanic ash from EFJ. Volcanic particles up to
6.5 @m were present, much larger than the conventional
dispersion model would predict. The maximum mass
concentration recorded inside the ash cloud by OPC was 330
@g/m3. On the filter, sampled during F2, clays, carbonates,
sulfates and quartz were present. Volcanic ash particles,
however, were almost absent.
Chemical fingerprints of in situ collected samples are one
way to ascertain the volcanic nature of an aerosol cloud.
CCSEM can deliver such fingerprints. We were able to
confirm the presence of the volcanic cloud over some parts of
north-western Germany the 18th May 2010, but also to show
that not all higher aerosol concentrations in the free
troposphere could be attributed to the presence of volcanic
ash. The obtained results from the measurement flights agree
with the model of VAAC at its scale.
Institut für Geologie und Paläontologie, WWU Münster,
48149 Münster, Germany
(*correspondence: [email protected])
2
Geological Survey of Norway (NGU), Trondheim, Norway
3
University of Bergen, Centre of Geobiology, Bergen, Norway
1
Major environmental upheavals of global nature
characterize the early Paleoproterozoic including the
deposition of unprecedented amounts of organic matter during
the Shunga Event ~2 billion years ago. Within the depositional
environment, this organic matter fueled respiratory processes,
among them the microbial reduction of an oceanic sulfate pool
that developed in the aftermath of the Great Oxidation Event
(GOE ~2.4 Ga). Ample evidence for microbially driven
turnover of sulfate is provided by sedimentary pyrite in the
organic-rich deposits of the Zaonega Formation, Onega
Paleobasin, NW Russia.
Three drillcores were obtained from the Zaonega
Formation in the course of the Fennoscandian Arctic Russia –
Drilling Early Earth Project (FAR-DEEP) under the auspices
of the International Continental Drilling Program (ICDP).
Organic carbon rich samples from the Zaonega Formation
contain abundant sedimentary Fe-sulfides exhibiting different
morphologies suggestive of multiple stages of sulfide
generations. In terms of diagenetic timing, these range from
early diagenetic sedimentary pyrite to late generation pyrite
and pyrrhotite occurring in cross cutting veins together with
migrated bitumen.
Different forms of sulfur (AVS: acid volatile sulfide; CRS:
chromium reducible sulfur) extracted from bulk rock samples
throughout the succession yielded highly variable &34S values
ranging between -8.1 and +25.6‰. Stratigraphic variations are
discernible. The observed range in &34S values is consistent
with a microbial origin via sulfate reduction and confirms
previously published sulfur isotope data [1]. Guided by
petrographic observations using transmitted and reflected light
microscopy, a detailed sampling of different pyrite generations
for subsequent sulfur isotopic work has been performed.
[1] Melezhik et al. (1999) Earth-Science Reviews 47, 1–40.
[1] Weber et al. (2011) Atm. Env. S-11-00415, submitted.
Mineralogical Magazine
1449
www.minersoc.org
1450
Goldschmidt Conference Abstracts
Dynamic subsurface biosphere
fuelled by organic matter from the
past
P. MEISTER1*, S. CONTRERAS QUINTANA1,2, B. LIU1,
A. KHALILI1,3, T.G. FERDELMAN1,
M. KUYPERS1 AND B.B. JØRGENSEN1,4
Max Planck Institute for Marine Microbiology, 28359
Bremen, Germany
(*correspondence: [email protected])
2
Large Lakes Observatory (LLO), University of Minnesota,
Duluth, MN 55812, USA
3
Earth & Space Sciences Program, School of Engineering and
Science, Jacobs University, 28725 Bremen, Germany
4
Center for Geomicrobiology, Århus University, 8000 Århus,
Denmark
1
Microbial degradation of organic matter deposited on the
seafloor and buried over geological time within marine
sediments leads to the onset of a redox zonation. This zonation
may strongly shift over geological timescales due to variations
of organic matter composition and burial rate. However, such
dynamics in subsurface redox zonation is generally not
obvious from measured porewater profiles.
Redox zonations may leave characteristic imprints in the
geological record and therefore document the diagenetic
history of a particular biogeochemical setting. We report the
finding of diagenetic barite and dolomite layers that document
past positions of the sulphate/methane transition zone (SMTZ)
at ODP Site 1229 drilled on the Peruvian continental shelf.
The layers co-occur with a focussed enrichment in isotopically
light archeol, a lipid biomarker indicative of anaerobic
methane oxidation.
Using a time-transient reactive transport model for
sulphate and methane allowed to reproduce a SMTZ migrating
upward and downward over a depth range of 30 m (below
seafloor) over a time period of 100 ka. These variations were
caused by variation in the organic matter content, the initial
age of organic matter, and burial rate. Organic matter was
assumed to decay according the reactive continuum model [1]
whereby the different parameters were constrained by bulk
TOC and 35S radiotracer rate data.
The diagenetic imprints and modelling results are
evidence of a sub-surface redox zonation more dynamic than
we would expect from measured porewater profiles.
Therefore, the diagenetic record in combination with nonsteady state geochemical modelling must be taken into
account for an assessment of diffusive fluxes between marine
sediments and the water column and their contribution to
global biogeochemical cycling.
Development of methodologies based
on Field-Flow Fractionation for the
characterization of engineered
nanoparticles in complex samples
B. MEISTERJAHN, S. LEGROS,
F. VON DER KAMMER* AND T. HOFMANN
Univ. of Vienna, Dept. of Env. Geosciences, Vienna, Austria
(*correspondence: [email protected])
Engineered nanoparticles (ENPs) are more and more
introduced into consumer products, leading to environmental
and health concern. This development has been so rapid that
methods to detect, quantify and characterize ENPs in
environmental and biological media are still widely lacking.
Field Flow Fractionation (FFF) is one of the most promising
techniques currently developed for these tasks.
The strategy adopted for the analysis of ENPs in complex
matrices depend strongly on the type of the ENPs and the
nature of the matrix. Therefore, different methodologies have
to be specifically developed for the e.g. analysis of
nanoparticles of silver (AgNP) in an environmental matrix and
nanoparticles of silica (SiO2NP) in a biological matrix. These
new developments have been performed on reference samples
and are presented here.
Standard AgNP (i.e. 15-20 nm NM300 from OECD
repository) were spiked to a standard soil (i.e. IME RefeSol
from the German Federal Environment Agency) while
Standard SiO2NP (here 40 and 100 nm) were spiked to tomato
soup (preparation from JRC in the course of FP7 Nanolyse
project). The sample preparation can be done by density
separation (AgNP) and by acid digestion (SiO2NP). Flow-FFF
coupled to UV-DAD spectrometry, online static and dynamic
light scattering and ICP-MS were used to characterize
compositions and properties of nanoparticles as a function of
size.
Conventional ICP-MS coupled to FFF seems to be suitable
for complex samples containing AgNP, because Ag has a low
background in the environment.
These optimized methods helped in the investigation of
complex mixtures of ENPs and matrix which finally led to the
conclusion that ENPs do not always intensively interact with
natural nanoparticles coming from the matrices and can occur
as stable single particles in the environment. This results
mitigate the current assumption that hetero-aggregation will be
the most probable mechanism occurring in the environment.
This is important in order to predict the impact of ENPs on the
environment and human health.
[1] Boudreau and Ruddick, (1991) Am. J. Sci. 291, 507-538.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Melts migrating through the mantle
wedge: evidences from Patagonian
and Western Pacific mantle xenoliths
M. MELCHIORRE1, B. FACCINI1, M. COLTORTI1,
M. GREGOIRE2, C. BONADIMAN1 AND M. BENOIT2
Department Earth Sciences, University of Ferrara, Italy
([email protected])
2
Observatoire Midi Pyrénéese, Université de Toulouse, France
([email protected])
1
A suite of anhydrous spinel-bearing mantle xenoliths from
Estancia Sol de Mayo (ESM, Patagonia) has been studied and
compared with a large number of mantle xenoliths from other
Patagonian localities. ESM xenoliths are devoid of modal
metasomatic features as well as of amphibole. ESM cpx and
opx plot on the high mg# side of three different trends,
depicted by peridotites and pyroxenites of the other Patagonia
localities. On the whole the three trends point towards
refertilization/metasomatic events caused by saturated and
undersaturated melts which largely affected the Patagonian
sublithospheric mantle. These melts are similar to those
responsible for the formation of various plateaux located
behind the Austral Volcanic Zone. Cpx and opx of mantle
xenoliths found in calc-alkaline lavas from the western part of
the Pacific plate are also included in the comparison. They
appear to be substantially depleted in Al2O3 and depict the
fourth distinct trend. Investigation is currently undertaken to
evaluate if this difference can be ‘simply’ related to different
partial melting degree or to compositionally distinct
metasomatic agents.
1451
Diverse mantle sources for Ninetyeast
Ridge volcanoes
P. MELENEY1*, F.A. FREY1, M. PRINGLE1, E. O’BRIEN1,
S. HUANG2, I. NOBRE SILVA3 AND D. WEIS3
EAPS, MIT, Cambridge, MA 02139, USA
(*[email protected])
2
EPS, Harvard University, Cambridge, MA 02138, USA
3
EOS, UBC, Vancouver, B.C., Canada V6T 1Z4
1
The Ninetyeast Ridge (NER) is a 5, 000 km long N-S
oriented submarine volcanic ridge in the eastern Indian Ocean.
The N to S linear decrease in age, 77 to 43 Ma, is consistent
with the NER forming as a hotspot track as the Indian Plate
migrated northward over the Kerguelen hotspot. In 2007 the
R/V Revelle recovered over 2, 000 kg of dominantly tholeiitic
basalt from 22 dredge sites along 3, 200 km of the NER. The
basalts have been variably altered in the submarine
environment and 7 whole rock-glass pairs show that Rb and U
are enriched and Ba is depleted in the altered whole rocks.
Based on abundance ratios of REE and HFSE, and their
correlations with Nd and Hf isotopic ratios, we identify
several mantle sources that contributed to formation of the
NER (see Fig. 1). We infer that two are related to the hotspot:
one enriched in incompatible trace elements similar to the
source of flood basalt in the Kerguelen Archipelago and the
other is depleted in incompatible elements, but some trace
element ratios (like Y/Nb) differ from the source of recently
erupted SEIR MORB [1] (see Fig. 2). A third source is
incompatible element-depleted similar to the source of SEIR
MORB; this source is consistent with the inferred proximity of
the hotspot to a spreading ridge during NER construction.
However, Sr and Pb isotopic ratios of acid-leached whole
rocks are not consistent with this inference [2, 3].
Figure 1: Dredges show trends between KA and SEIR EMORB and N-MORB
Figure 2: Y/Nb anomalies in NER basalts.
[1] Frey et al. (2011) EPSL 303 315–224. [2] Nobre Silva et
al. (2007) GCA 71, 15S A721. [3] Nobre Silva et al. (2011)
PhD Thesis UBC.
Mineralogical Magazine
www.minersoc.org
1452
Goldschmidt Conference Abstracts
Abundant marine sulphate in the
Palaeoproterozoic: Models come and
go, but the rock record endures
V.A. MELEZHIK1,2*, A.E. FALLICK3, D.V. RYCHANCHIK4
AND FAR-DEEP DRILLING TEAM
NGU, Postboks 6315, N-7491 Trondheim, Norway
(*correspondence: [email protected])
2
University of Bergen, Postboks 7803, N-5020 Bergen,
Norway
3
SUERC, East Kilbride, Glasgow G75 0QF Scotland
4
Geological Institute, 185610 Ptrozavodsk, Russia
1
An important consequence of progressive oxygenation of
the Earth’s biosphere through the Proterozoic was an
increased rate of sulphide oxidation during continental
weathering, with concomitant increase in marine sulphate
concentration. Hence, accurate assessment of the marine
sulphate reservoir is crucial for correct interpretation and
reconstruction of the oxygenation history of Earth’s early
emvironments. The currently accepted view is that the
Proterozoic biosphere shows protracted oxidation, but marine
sulphate remains low until c. 800 Ma [1]. This view and the
estimated size of the marine sulphate reservoir through the
Proterozoic, was essentially based on (i) a model that involves
S isotope variability, and (ii) the absence of massive Casulphates in the geological record until the late
Mesoproterozoic. A contrasting, and less popular view, based
on geological evidence, suggests otherwise [2]. Recently, the
controversy has been resolved by discovery of massive
anhydrites [3]. At a depth of 2115 m in a c. 3500-m-deep
drillhole in the Onega Basin in eastern Fennoscandian Shield
13
C-rich dolostones of Lomagundi-Jatuli age (335 m) were
intersected followed by massive anhydrite and anhydritemagnesite rocks (c. 100 m), nodular shale interbedded with
massive anhydrite (190 m) and a c. 194-m-thick halite
formation (70-75% halite, 12-20% anhydrite, 10-15%
magnesite) containing large blocks (up to 1 m) of bedded,
coarse-grained anhydrite and magnesite. The c. 500-m-thick
sulphate-halite interval survived orogenic deformation and
associated greenschist metamorphism. Thick dissolutioncollapse breccias occurring basin-wide at more shallow depths
suggest that the preserved section represents only a small
fraction from that what was originally precipitated. Hence, the
geological record in the Onega basin endured and revision of
current models is essential.
U-Pb dating of columbite-tantalite
from Variscan rare-elements granites
and pegmatites
J. MELLETON1, E. GLOAGUEN1, D. FREI2 AND A. LIMA3
BRGM, Mineral Resources Division, Orléans, France
([email protected], [email protected])
2
Stellenbosch University, Central Analytical Facility &
Department of Earth Sciences, Stellenbosch, South Africa
([email protected])
3
Porto University, Center of Geology, Porto, Portugal
([email protected])
1
Rare-elements (Li, Cs, Ta, Be, Sn…) magmatism is well
expressed in the European Variscan belt with mainly
pegmatites and granites. These bodies are known in most of
the different realms of the belt, but they are particularly
abundants in localized parts of the Iberian massif, the French
Massif Central and the Bohemian Massif.
U-Pb dating of columbite-tantalite from selected Variscan
rare-elements granites and pegmatites of these three massifs
has been performed using laser ablation system connected to a
single collector magnetic SectorField - Inductively Coupled
Plasma - Mass Spectrometer (LA-SF-ICP-MS). The main
aims of this study are to investigate the timing of this
magmatism in the Variscan belt and the chronological
relationship with the surrounding granitoid suites. Our results
highlighted the existence of several emplacement episods :
-
in the Moldanubian domain of the Bohemian Massif,
rare-elements pegmatites emplaced at around 340330 Ma.
in the North of French Massif Central, the
Montebras and Beauvoir granites and the Chèdeville
pegmatite lead to emplacement age at 315-310 Ma.
in the North of Iberian massif, three different events
have been recognized, with the emplacement of the
Argemela granite at 326 ± 3 Ma, a first group of
pegmatites emplaced at 310 ± 5 Ma, a second at 301
± 3 Ma.
In this context, rare-elements magmatism do not look to be
related to lower crust processes (i.e. granulitic metamorphism)
and rare metal magmatism event appears diachroneous and
polyphased.
[1] Kah et al. (2004) Nature 431, 834–838. [2] Melezhik et al.
(2005) Terra Nova 17, 141–148. [3] Morozov et al. (2010)
Doklady Earth Science, Geochemistry 435, 230–233.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Microbial iron(II) oxidation in
littoral freshwater lake sediments;
Competition between phototrophic
versus nitrate-reducing iron(II)oxidizers
E.D. MELTON*, C. SCHMIDT AND A. KAPPLER
Geomicrobiology, University of Tuebingen (*correspondence:
[email protected])
The temporal and spatial distribution of microbial iron
redox transformations are determined by local geochemical
conditions and the resident microbial diversity. In the anoxic
part of the top layer of littoral freshwater lake sediments,
nitrate-reducing and photoferrotrophic microorganisms
compete for the same electron-donor, i.e. reduced iron.
Though a conceptual framework for biogeochemical iron
cycling has been proposed [1], it is not yet empirically
understood how these microbes co-exist in the sediment, what
their spatial distribution is relative to one another and what
role they play in the overall iron cycle. In this study,
freshwater littoral lake sediment from Lake Constance was
incubated in microcosm experiments with various additives to
stimulate microbial photoferrotrophic and nitrate-reducing
iron (II) oxidation in order to distinguish between the two
processes and assess their individual contributions to the
sedimentary iron cycle. One set was incubated under constant
light, whilst a parallel set was incubated in the dark at 23°C.
Additionally, a high-resolution MPN depth profile was
performed for iron (II)-oxidizing organisms utilizing light or
nitrate to reveal their spatial distribution in the natural
sediment. These experiments combine microbial and
geochemical techniques to provide key information needed not
only to determine the contribution of microbial activity to the
overall iron oxidation budget and their spatial distribution, but
also to define the role of geo (photo)chemical iron conversion
rates and its general importance in littoral freshwater lake
sediments.
[1] Schmidt et al. (2010) Environmental Chemistry 7, 399–
405.
Mineralogical Magazine
1453
Unraveling microbes-minerals
interactions in the deep biosphere
B. MENEZ1,2*, E. GERARD1,2, D. BRUNELLI3, V. PASINI31,
P. LE CAMPION1,2, S. DUPRAZ1,2, M.C. MARINOZZI1,2,
M. AMOR1 AND F. GUYOT1,24
IPGP, UMR CNRS 7154, 1 rue Jussieu, 75005 Paris, France
(*correspondence: [email protected])
2
Centre de Recherches sur le Stockage Géologique du CO2
(IPGP/TOTAL/SCHLUMBERGER/ADEME)
3
Dipartimento di Scienze della Terra, Università di Modena,
L.go St. Eufemia 19, 41100 Modena, Italy
4
IMPMC, UMR CNRS 7590, 4 place Jussieu, 75005 Paris,
France
1
Subsurface environments harbor diverse and active
microbial populations that influenced the Earth’s chemistry
throughout geological times by mediating elemental fluxes
from the lithosphere to the oceans and atmosphere. However,
the exploration of their metabolic diversity, energy sources,
and biogeochemical transformations at the appropriate scale
remains highly challenging, especially within hard rocks. We
present here dedicated cutting-edge approaches combining
molecular labelling (as fluorescence in situ hybridization and
immunodetection) with an array of high-resolution techniques
(coupled confocal laser scanning microscopy and Raman
spectroscopy,
transmission
and
scanning
electron
microscopies, synchrotron-based X-ray microimaging).
Altogether they allow localizing specifically individual
prokaryotic cells, investigating their phylogenetic affiliation at
the micrometric scale while characterizing concomitantly the
nature and the stucture of their microhabitats and past
interactions (i.e. mineral dissolution and metabolic byproducts
such as biomineralizations). Our ability to reveal chemical,
mineralogical, genetic and metabolic diversity in subsurface
environments will be illustrated by integrated field and
laboratory investigations. Special attention will be dedicated
to hydrogen-driven chemolithoautotrophic ecosystems
associated with ultramafic rocks from the oceanic lithosphere,
in the double fundamental perspective: to explore analogs for
early biological systems on the primitive Earth or other
planetary bodies, and for industrial purposes being a major
target for CO2 geological storage where microbial activity
allow enhancing carbonation processes and reducing the
energetic balance.
www.minersoc.org
1454
Goldschmidt Conference Abstracts
Late Paleozoic tectonic evolution in
eastern Heillongjiang Province, NE
China: Constraints from detrital
zircons and volcanisms
E. MENG, W.L. XU*, F.P. PEI AND F. WANG
College of Earth Sciences, Jilin University, Changchun
130061, China ([email protected])
(*correspondence: [email protected],
[email protected])
Geochronology of detrital and magmatic zircons and
geochemistry of the volcanic rocks from the late Paleozoic
strata in eastern Heilongjiang province of NE China, provide
constraints on the Late Paleozoic tectonic evolution of the
eastern segment of the Central Asian Orogenic Belt between
the Siberian and the North China cratons [1].
LA-ICP-MS U-Pb dating results for detrital zircons from
the Early Devonian sandstones show that the detrital zircons
from the rocks in the Songnen-Zhangguangcai Range Massif
(SZM) have age populations of 2503, 1833, 903~802, and
551~403 Ma, different from those from the coeval rocks in the
Jiamusi Massif (JM) with ages of 569, 542, 509, and 484 Ma
[2]. This finding indicates that (1) they deposited after 403 and
484 Ma, respectively; (2) ancient crustal remnants existed in
the SZM in the Late Paleozoic; (3) the amalgamation of the
SZM and JM could happen before 403 Ma.
Zircon U-Pb dating results for the magmatic zircons from
the Late Paleozoic volcanic rocks in the region indicate that
three volcanical events exist in the Late Paleozoic, i.e. the
Middle Devonian (386 Ma), Early Permian (291 Ma), and
Middle Permian (268 Ma). Their geochemical data and Sr-NdHf isotopes reveal that: (1) the Middle Devonian volcanic
rocks in eastern margin of the JM consist of basalt and
rhyolite, a bimodal volcanism, suggesting an extensional
environment, which is consistent with the existence of coeval
A-type rhyolites in the SZM; (2) the Early Permian volcanic
rcoks in the eastern margin of the JM are composed mainly of
a calc-alkaline volcanic rocks such as basalt, basalt-andesite,
and minor dacite, indicating an active continental margin
setting, whereas the coeval bimodal volcanical rocks in the SZ
suggests an extensional environment similar to a back-arc
basin setting [3];. and (3) the Middle Permian syn-collisional
rhyolites in the southeastern margin of the JM imply the
amalgamation of the JM and the Khanka Massif.
[1] Sengör A.M.C. et al. (1993) Nature 364, 299–307.
[2] Meng et al. (2010) Tectonophysics. 485, 42–51. [3] Meng
et al. (2011) J. Asian Earth Sci. 41, 119-132.
Mineralogical Magazine
Hf-Nd isotope decoupling during
partial melting of thickened eclogitic
lower continental crust
F.X. MENG1*, S. GAO1,2, W.L. XU3, J.L. GUO1
2
AND C.L. ZONG
State Key Laboratory of Geological Processes and Mineral
Resources, China University of Geosciences, Wuhan
430074, China (*correspondence: [email protected])
([email protected])
2
State Key Laboratory of Continental Dynamics, Northwest
University, Xi’an 710069, China
3
School of Earth Sciences, Jilin University, Changchun
130061, China ([email protected])
1
Worldwide granulites usually do not exhibit decoupled
Hf-Nd systems expected for crustal melting at the presence of
garnet. Here we present whole-rock Nd–Hf isotopic data for a
rare suite of lower crustal eclogitic xenoliths and their host
early Cretaceous high-Mg adakitic porphyries from the
Xuhuai area from the eastern North China craton. The
xenoliths and their host intrusions are considered to represent
residues and melt formed by melting of eclogitic lower crust
that foundered into the convecting mantle based on their
complementary major and trace element compositions and
similar zircon age patterns. Nine of the eleven analyzed
xenoliths plot significantly above the terrestrial Hf-Nd array
with !Hf up to +60, while the porphyries fall essentially along
the array. Hf-Nd isotopic modelling shows that the eclogitic
xenoliths can be interpreted by 30-50% extraction of melt,
which after reaction with 10-30% depleted mantle can produce
the observed porphyry. The retarded time-integrated Hf
isotope ingrowth of the porphyries is due to its very low Lu/Hf
ratio and a relatively short time span after its formation. Our
results also indicate that garnet is the major factor controlling
Lu/Hf ratio of the residue with accessory minerals rutile and
titanite also playing a role. Granulite with <10% garnet will
not evolve to show significant decoupled Hf-Nd isotopic
signatures even after 500 Ma of melt extraction. The generally
terrestrial Hf-Nd compositions of worldwide granulites may
be because they have never experienced partial melting at
presence of abundant garnet. Instead, the lower crustal
granulite may transform into eclogite during crustal
thickening. Such an eclogitic lower crust is short-lived, and
will be recycled into the mantle. Decoupled Hf-Nd isotopic
signatures are expected to be more pronounced in eclogite
foundering-related basaltic magma than eclogite-derived TTG
melt, as observed in some of Cenozoic basalts from the eastern
North China craton.
www.minersoc.org
Goldschmidt Conference Abstracts
Thermometry of quartz from the
metaconglomerate of Jack Hills,
Western Australia
M. MENNEKEN1*, A.A. NEMCHIN2 AND T. GEISLER3
Institut für Mineralogie, Westf. Wilhelms Univ. Münster
Correnstr. 24, 48149 Münster , Germany
(*correspondence: [email protected])
2
Department of Applied Geology, Curtin Univ. of Technlogy,
Kent Str. Bentley, 6102 WA, Australia
3
Steinmann Institut, Rheinische-Friedrich-Wilhems Univ.
Bonn, Poppelsdorfer Schloss, 53115 Bonn, Germany
1
The original sample site W74 in the Jack Hills metasedimetary belt, Western Australia [1], is well known for
containing detrital zircon grains as old as 4.4 Ga [2]. Various
geochemical investigations on these detrital zircons and their
inclusions have been utilized in trying to establish conditions
that existed on the early Earth [3 and ref. therein]. We
extended the focus of this research to quartz, the main
component of the conglomerate containing old zircons. In a
comparative study we determined Ti temperatures of quartz
[4] in both the quartzite pebbles and the matrix of the
conglomerate, as well as of quartz from inclusions in zircons.
The quartz grains of the conglomerate pebble record an
average temperature of 437 ± 22°C (2$, n=21), which is
significantly lower than the temperature of 509 ± 80°C (n=15)
obtained from the matrix quartz. The temperatures obtained
from quartz inclusions in separated zircon grains, on the other
hand, are all around 700°C, and are in agreement with Ti-inzircon temperatures obtained from the host zircons, proving
previous assumption that the quartz inclusions were
incorporated during zircon growth. We interpret the matrix
quartz temperature as recording the late metamorphism of the
Jack Hills sedimentary belt at upper greenschist lower
amphibolite conditions [5]. The pebble quartz, however, might
inherit the temperature of an earlier metamorphic event in the
source region. This, in combination with the restriction of the
mineral paragenesis to nearly purely quartz, suggests that
grains, deposited in the Jack Hill sedimentary belt, are derived
from a meta-sedimentary host rock. Zircons, found in the
conglomerate, would thus have experienced at least one
metamorphic event before being re-deposited in the Jack Hill
sedimentary belt.
[1] Compston & Pidgeon (1986) Nature 321 766–769.
[2] Wilde et al. (2001) Nature 409 175–178. [3] Kemp et al.
(2010) EPSL 296 45–56. [4] Wark & Watson (2006) Contrib
Mineral Petrol 152 743–754 [5] Rasmussen et al. (2010)
Precambrian Research 180 26–46.
Mineralogical Magazine
1455
SoilTrEC: An international
consortium to assess soil processes
and functions using a global network
of Critical Zone Observatories
M. MENON AND SOILTREC RESEARCH TEAM
Kroto Research Institute, University of Sheffield, Broad Lane,
Sheffield, S3 7HQ, United Kingdom
([email protected])
Soil Transformation in European Catchments (SoilTrEC)
is an international consortium that aims to develop a
comprehensive understanding of soil processes and functions.
The project will combine experiments and modelling to
describe soil formation and functions using a global network
of Critical Zone Observatories (CZOs) that focus
multidisciplinary expertise onto the study of soil processes.
The specific objectives of the project are the following: (1)
describe from 1st principles how soil structure impacts
processes and function at soil profile scale, (2) establish 4 EU
Critical Zone Observatories to study soil processes at field
scale (3) develop a Critical Zone Integrated Model of soil
processes and function (4) create a GIS-based modelling
framework to delineate soil threats and assess mitigation at EU
scale (5) quantify impacts of changing land use, climate and
biodiversity on soil function and economic value (6) form with
international partners a global network of CZOs for soils
research, and (7) deliver a programme of public outreach and
research transfer on soil sustainability [1].
Four experimental CZOs are chosen for this study [1]; the
Damma Glacier CZO (Switzerland) allows the study of
incipient soil formation in the glacial forefield as the glacier
retreats, to study earliest stages of soil formation. Lysina CZO
(Czech Republic) and Fuchsenbigl CZO (Austria) are included
to study soil processes under well managed forest and arable
landscapes, respectively. The Koiliaris CZO (Greece)
represents highly degraded soils after millennia of intensive
agricultural land use, including grazing, and is under
additional threat from desertification due to modern climate
change. These CZOs provide field data and new
measurements which will be used for the modelling of water
flow, reactive transport, biogeochemical processes and
nutrient cycles. Finally, an intergrated regional scale model
will be developed for soil ecosystem services and threats in
Europe, which will be further validated with other CZOs in
Europe, USA and China. Soil profile sampling from the CZOs
was completed in 2010 and preliminary data will be presented.
[1] Banwart et al. Vadose Zone Journal (in review).
www.minersoc.org
Goldschmidt Conference Abstracts
1456
Quantitative reconstruction of
millennial-scale temperature
variations in Central Europe
G. MENOT* AND E. BARD
CEREGE, Univ. Aix-Marseille, CNRS, IRD & College de
France, Technopole de l'Arbois BP 80, 13545 Aix-enProvence Cedex 04, France
(*correspondence: [email protected], [email protected] )
The amplitude of the environmental changes associated
with the Last Deglaciation provides a useful test bench for the
climatic and oceanic responses and their attendant feedbacks
to major reorganizations of the atmospheric circulation and the
surface hydrology. We present the first quantitative
reconstruction of millennial-scale temperature variations in
Central Europe during the last 40, 000 years based on newly
developed temperature proxies measured in a sediment core
from the Black Sea (MD04-2790). Despite the shift from
lacustrine to marine conditions (and therefore associated
salinity changes) that affected the basin, the tetraether-based
paleothermometer (TEX86) properly records the increase in
surface water temperatures during the Last Deglaciation. To
our knowledge, no quantitative temperature reconstruction has
been published for the Black Sea area so far, a comparison of
the amplitude of temperature changes reconstructed for the
Last Glacial Maximum and the actual in the Mediterranean
basin shows that the Black Sea values are consistent with that
of the western basin and colder than the eastern basin [1].
Interestingly and in contrary to what is seen in nearby archives
(pollen assemblages [2], [3] and speleothems [4]) Heinrich
events deeply imprint our glacial temperature record, whereas
the signature of Dansgaard-Oeschger interstadials are
comparatively attenuated. The high-resolution record also
provides snapshots of the basin responses to specific abrupt
climatic events such as the Younger Dryas and the BøllingAllerød.
Application of thermal analysis and
NMR to study soil organic matter
biodiversity and biodegradability in
afforested lands
AGUSTÍN MERINO*, CÉSAR PÉREZ-CRUZADO,
JOSEFA SALGADO AND NIEVES BARROS.
Escuela Politécnica Superior, University of Santiago de
Compostela, Lugo, Spain
Calorimetry and thermal analysis can be applied to studies
of the stabilization of soil organic matter (SOM) under
different environment situations and types of management. In
this study, differential scanning calorimetry (DSC) and
isothermal calorimetry were applied, along with 13C CPMAS
NMR, to assess the changes in SOM quality in afforested
lands under pine and eucalypt in a humid temperate region.
Samples with the highest carbon percentages contained
highly diverse mixture of aliphatic fractions, carbohydrates,
cellulose, aromatic C and carboxyl groups. The heat of
combustion was also highest in these samples. The loss of
SOM and the C decay affected the aliphatic fraction and
carbonyl groups, which could not be identified in the NMR
spectrum or in the DSC curves of those samples.
Carbohydrates and aromatic C persisted in the samples with
the lowest C percentages. C gain after afforestation
predominantly affected the aliphatic and aromatic fractions in
the pine stands and the aliphatic and carbohydrate fractions in
the eucalypt stands. The method was sensitive to detect
differences in the OM nature attributable to the tree species.
[1] Hayes et al. (2005) Quaternary Science Reviews 24, 999–
1016. [2] Naughton et al. (2007) Marine Micropaleontology,
62, 91–114. [3] Fletcher et al. (2010) Quaternary Science
Reviews, 29 (21-22) 2839–2864. [4] Fleitmann et al. (2009)
Geophys. Res. Let. 36.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Sr-Nd-Pb-Os isotopes of CAMP
tholeiites from northeast America
R. MERLE1*, A. MARZOLI1, H. BERTRAND2,
L. REISBERG3, M. CHIARADIA4 AND G. BELLIENI1
Università di Padova, via Gradenigo 6, 35100 Padova, Italia
(*correspondence: [email protected])
([email protected], [email protected])
2
UMR-CNRS 5570, 46 Allée d’Italie, 69364 Lyon, France
([email protected])
3
CRPG (CNRS UPR2300), BP 20, 54501 Vandoeuvre-lèsNancy, France ([email protected])
4
Université de Genève, 13 rue des Maraîchers, 1205 Genève,
Switzerland ([email protected])
1
The Central Atlantic Magmatic Province (CAMP) is one
of the largest CFB provinces on Earth, extending over a
surface in excess of 107 km2 in circum-Atlantic regions. Here
we document the geochemical characteristics of CAMP lavas
flows, sills and dikes from NE U.S.A. and Nova Scotia
(Canada).
All the samples are low-Ti basalts and compared to NMORBs they display LILE and LREE enriched patterns with
negative Nb anomalies. Based on major and trace element
characteristics (REE patterns, TiO2 vs La/Yb diagrams), three
groups can be defined: (1) the Talcott-Orange-Mt Zion Church
flow units, all the Nova Scotia samples (North Mountain
basalts and Shelbourne dike) and the lower part of the
Palisades sill (TiO2 A 0.5-1.3 wt%, La/Yb A 4-6), (2) the
Holyoke-Preakness-Sander-Hickory flow units (TiO2 A 0.7-1.1
Wt%, La/Yb A 2.5-3.5) and (3) the Hampden-Hook flow units
(TiO2 ~ 1.3-1.5 wt%, La/Yb ~ 2).
All the samples plot in the field of CAMP low-Ti basalts
in Pb-Pb and Sr-Nd isotope plots (206Pb/204Pb = 18.16-18.69,
207
Pb/204Pb = 15.57-15.67, !Nd from -4.1 to 2.3). Most of the
samples display initial 187Os/188Os ratios in the range of typical
upper mantle magmas. Nevertheless, some samples have quite
radiogenic initial ratios (up to 0.479) suggestive of crustal
contamination.
The Talcott-Mt Zion Church-Orange-North MountainShelbourne group shows continental-like Sr-Nd-Pb isotopic
ratios, which coupled with their mostly non-radiogenic Os
compositions, may argue for a dominant source contribution
from subduction-metasomatised sub-continental lithospheric
mantle (SCLM). The Hook-Hampden and the HolyokeSander-Preakness-Hickory units as well as the Rapidan sill are
slightly distinct from the other samples since they yield
206
Pb/204Pb >18.5 and are closer to the NHRL. These
characteristics may suggest a contribution from an
asthenospheric component.
1457
Evaluating the impact of marine
organic aerosols on climate
NICHOLAS MESKHIDZE, JUN XU AND BRETT GANTT
Department of Marine, Earth, and Atmsospheric Sciences,
North Carolina State University, Raleigh, NC, USA
([email protected], [email protected],
[email protected])
A large fraction of the uncertainty in predicting future
climate may be related to the number concentration of marine
aerosol that are prescribed or diagnosed in global climate
models. Therefore, correct assessments of aerosol number
concentration, size distribution and chemical composition over
pristine marine regions may have profound effect on model
predicted extent of human-induced climate change.
The effects of marine organic aerosols on microphysical
properties of shallow clouds and the Earth’s radiative budget
are explored by the NCAR Community Atmosphere Model
(CAM5.0), coupled with the PNNL Modal Aerosol Model.
Sea spray enrichment by organics is estimated using wind
speed dependent size-resolved parameterization, while
marine-source secondary organic aerosol is inferred from the
ocean emissions of biogenic trace gases. The ability of sea
spray to act as cloud condensation nuclei (CCN) are not fully
understood; therefore CAM5 simulations cover the range of
possible scenarios in aerosol mixing sate and hyroscopicity
parameter based on our recent lab experiments. The size,
number, and CCN distributions of aerosols generated by a
bubble-bursting process were determined using a differential
mobility analyzer (DMA)-condensation particle counter
(CPC)-CCN counter (CCNc) system. Predicted concentration
of organic aerosol and CCN in remote marine atmosphere was
compared to in situ data. Simulations show that over the
oceans marine organics can yield up to 10% increase in
surface CCN (0.2%) (see Fig. 1). Changes associated with
liquid water path and droplet number can increase short-wave
forcing by -0.2Wm-2. The disproportional effects of marine
aerosols between pre-industrial and current climate and land
vs. ocean have also been observed.
Figure 1: Annual average percentage change in surface CCN
(0.2%) concentration due to marine emissions.
Mineralogical Magazine
www.minersoc.org
1458
Goldschmidt Conference Abstracts
Evolution of the " D value in waterrich basaltic melt inclusions during
volcanic processes
N. METRICH1*, E. DELOULE2 AND A. DI MURO1
Institut de Physique du Globe, Sorbonne Paris Cité, UMR
CNRS 7154, Univ. Paris Diderot, Paris, France
(*correspondence: [email protected], [email protected])
2
CRPG-CNRS, Vandoeuvre Les Nancy, France
([email protected])
1
Melt inclusions (MIs) hosted in Mg-rich olivines are
powerful tools to record magma evolution and degassing
during their decompression and ascent toward the surface.
However their ability to loose H2O during magma ascent and
degassing through proton diffusion is widely debated [e.g. 1].
H2O contents and "D values were measured in two series
of melt inclusions representative of Ca-rich basalts to arc
basalts, rich in H2O, in using the Cameca IMS 1270 ion
microprobe (CRPG-CNRS, Nancy, France) and Raman
spectroscopy (Saclay, France, [2]), respectively. In lapilli
samples from Vulcano island (Aeolian arc), MIs are hosted in
olivine Fo89-90, they contain on average 4.4 wt% of H2O (±0.2
wt%; 18 measurements) and the post-entrapment olivine
crystallizaton is negligible. In Aoba samples (Vanuatu arc),
MIs are entrapped in olivine Fo86-90, with 2 to 5 % of postentrapment crystallization; their H2O is more variable (1.7-2.3
wt%). In both cases their low CO2 concentrations indicate
shallow olivine crystallization.
As a whole the "D values (42 measurements) vary from
-96‰ to +38‰ (with two values even higher). Isotopic
analyses have been duplicated in single inclusions of Vulcano
samples to verify the data reproducibility.
Hydrogen diffusion out of Mis is required to explain
negative trends between the H2O concentrations and "D, in
particular in one series of Aoba samples showing "D values
%0‰. Leaving apart these latter values, most of
the measured "D are comprise between -19‰ and -40‰. They
plot in the field of Mariana arc Mis (from -55‰ to -12‰; [3]).
The question that arises is to what extent our "D values are
representative of the last stage of melt equilibration with their
surroundings at time of their entrapment and olivine
crystallization or bring constraints on the magma source. The
different processes able to reproduce the trends registered by
Aoba and Vulcano MIs will be discussed.
[1] Gaetani et al. (2009) Eos Trans AGU 90(52) Fall Meeting
supp. Abst. V51E-1770. [2] Mercier et al. (2010) Geochim
Cosmochim Acta 74, 5641–5656. [3] Shaw et al. (2008) Earth
Planet. Sci. Lett. 275, 138–145.
Mineralogical Magazine
Am(III) retention by cement
corrosion products under highly
saline conditions
V. METZ, C. BUBE, E. BOHNERT, M. SCHLIEKER
AND B. KIENZLER
Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute
of Technology, Herrmann-von-Helmholtz-Platz, 76344
Eggenstein-Leopoldshafen ([email protected],
[email protected], [email protected], [email protected],
[email protected])
Cementition is a common method to fix and solidify low
and intermediate radioactive waste (LLW/ILW). Alteration of
radionuclide bearing cement products in diluted aqueous
solutions has been studied quite extensively. Yet, in chloriderich solutions, which are relevant for final LLW/ILW disposal
in rock salt, there is still a lack of thermodynamic data and
understanding with respect to both cement corrosion and
radionuclide behaviour. In the present work, cement
interaction with MgCl2-rich brines have been studied
experimentally on laboratory-scale and with full-scale waste
simulates. In addition, Am (III) retention by cement corrosion
products was quantified from the laboratory experiments.
Due to dissolution of portlandite, ettringite and other solid
cement phases, the initially MgCl2-rich solutions alter to
alkaline CaCl2-rich solutions. Besides reprecipitation of
gypsum, formation of hydrotalcite phases, Mg-Ca-Al
hydroxochloride and brucite is observed. Compositions of the
altered solution and solid phases depend strongly on the
cement / brine ratio. Measured solution compositions agree
well with results of thermodynamic calculations for the
studied cement / brine systems. After equilibration of the
systems, they are doped with small quantities of acidic 241Am
(III) and 243Am (III) solutions (10-9, 10-8 and 10-7 mol Am (kg
H2O)-1). Am concentrations and solution composition have
been monitored for 1000 days in the non-agitated batch
experiments. Within six months a sorption equilibrium is
achieved, demonstrating strong retention of Am (III) by the
corroded cement products. Data of equlibrated systems are
characterized by linear sorption isotherms, which allow
determining apparent sorption coefficients, Rs. In MgCl2CaCl2 and weakly alkaline CaCl2 systems (7.3 < -log (mH+)
<9.0), Rs is measured in the range of 3000 to 6000 ml g-1,
whereas in highly alkaline CaCl2 systems (-log (mH+) ~ 11.5)
Rs = 10000 ml g-1 is observed. The retention of radionuclides
on corroded cement products has often been claimed not only
for dilute solutions, but also for saline brines. This work
enables to quantify the retention of Am and thus corroborates
previous estimations with experimental data.
www.minersoc.org
Goldschmidt Conference Abstracts
Coupled high-resolution #13Ccarb and
87
Sr/86Sr chemostratigraphy on the
North American craton: Identifying
the source of the Late Ordovician
Guttenberg Isotopic Carbon
Excursion
J.G. METZGER AND D.A. FIKE
Dept. of Earth and Plentary Sciences, Washington Univ., St.
Louis, MO 63130, USA. ([email protected],
[email protected])
The Guttenberg isotopic carbon excursion (GICE) is a
~2‰ positive excursion in &13Ccarb found in Late Ordovician
(Early Katian) strata on three different continents and
represents a major perturbation of the global biogeochemical
carbon cycle. We applied &13Ccarb chemostratigraphy to two
Missouri (MO) sections containing the GICE in the Decorah
Formation. Our data show the Kings Lake Member of
southern MO and the Guttenberg Member of northern MO are
coeval rather than successive, thereby revising the erosional
and depositional history of Late Ordovician sediments in MO.
The cause of the GICE remains uncertain. Although
enhanced burial of organic carbon is often invoked, definitive
evidence for this has yet to arise. We couple &13Ccarb and
87
Sr/86Sr chemostratigraphy with biogeochemical cycling
models of C and Sr to constrain possible causes for the GICE.
Parallel variation in "13Ccarb and 87Sr/86Sr suggest a change in
oceanic weathering inputs as the most likely explanation for
the GICE. Modelling results indicate that a single mechanism,
a drop in the total weathering flux (Fw) and/or proportion of
silicates being weathered, can explain the apparent inverse
relationship between &13Ccarb and 87Sr/86Sr in our two sections
from MO. The drop in Fw could have resulted from flooding of
the North American craton, which thereby lowered the amount
of exposed land. Significant stratigraphic evidence of sea level
rise is found across the North America craton and is
coincident with the onset of the excursions in both isotopic
systems. However, a widespread drowning surface at the endGICE across the Upper Mississippi Valley suggests a
decoupling between &13Ccarb and sea level or the presence of
more than one mechanism. Despite the challenges of nonuniqueness in reconciling chemostratigraphy and model
results, we are able to show that coupling multi isotopic
systems and elemental cycling models can constrain the range
of possible source mechanisms, while precluding others.
Furthermore, our results suggest that small excursions in
87
Sr/86Sr may exist over relatively short periods of time (<1
Myr) in Paleozoic deposits.
Mineralogical Magazine
1459
Characteristics and origin of the Lala
iron oxide Cu-Co-(U, REE) deposit:
Sichuan, Southern China
F.M. MEYER1*, C. SCHARDT1, S. SINDERN1,
M. GEHLEN1, P.E. HALBACH2, J. LAHR2 AND J. LI3
Institute of Mineralogy and Economic Geology, RWTH
Aachen University, Wüllnerstr. 2, 52062 Aachen,
Germany (*correspondence: [email protected])
2
Institute of Geological Sciences, Free University Berlin,
Malteserstr. 74-100, 12249 Berlin, Germany
3
Qingdao Institute of Marine Geology, 62 Fuzhou Nan Road,
Qingdao, 266071, People’s Republic of China
1
Cu-Co-REE-U mineralization at the Lala mine is
multistage, controlled by the geologic-tectonic evolution of
the region. The deposit has been interpreted as volcanic-hosted
massive sulfide [1], metavolcanic-sedimentary with
hydrothermal remobilization [2], or IOCG-type mineralization
[3, 4]. The ore deposit is hosted by a Middle Proterozoic
volcano-sedimentary succession, metamorphosed at uppergreenschist to amphibolite-facies conditions, early during the
Sibao Orogeny (~1 Ga). Mineralization occurred during the
Neoproterozoic at ca. 830 Ma [5].
The host rocks are metamorphosed and hydrothermally
altered intermediate to mafic volcanics and mica schist. The
main alteration styles include albitization and sericitization.
Textural evidence allows recognition of 3 modes of sulphide
mineralization with a distinct sequence of formation,
indicating a complex and multiphase genetic evolution. There
are strong indications that the mineralization is essentially
epigenetic-hydrothermal in origin and the formation of
hydrothermal breccias may be attributed to fluid release from
an underlying magma. While there is no strict statistical
correlation between La and Cu, Cu-rich samples are always
enriched in REE elements. Other characteristic features
include the abundance of iron-oxides and Cu-sulfides, a lowTi magnetite chemistry, REE-mineralogy, and the presence of
uraninite.
These new data lend evidence to the conclusion that, in
contrast to previously proposed ore genesis models, the
mineralization at Lala possesses many features that warrant its
inclusion within the global IOCG deposit class.
[1] Zaw et al. (2007) Ore Geol. Rev. 31, 3–47. [2] Baoyong &
Zhengnan (1986) J. Min. Pet. 6, 111–121. [3] Wang et al.
(2005) GCA 69, 573. [4] Li et al. (2002) Bull. Chin. Soc. Min
Petr. Geochem. 21, 258–260. [5] Sun et al. (2006) Geochim.
35, 553–559.
www.minersoc.org
1460
Goldschmidt Conference Abstracts
Biogeochemical cycling in shallow-sea
and terrestrial hydrothermal systems
D’ARCY R. MEYER-DOMBARD1*, DAWN CARDACE2,
SARA T. LOIACONO1, YASEMIN GÜLEÇAL1,3,
KRISTIN WOYCHEESE1 AND JAN P. AMEND4
University of Illinois at Chicago
(*correspondance: [email protected], [email protected],
[email protected])
2
University of Rhode Island ([email protected])
3
Istanbul University ([email protected])
4
Washington University in St. Louis ([email protected])
1
Mounting evidence indicates that microbial diversity
varies substantially between hydrothermal systems of differing
provenances. For example, among terrestrial hydrothermal
systems, it has been shown that diversity and distribution of
microorganisms may be related to geographical location or
physical separation [1, 2]. There is, however, minimal
evidence concerning differences in the diversity and
distribution of genes associated with biogeochemical
functions. Of particular interest is the nature of
biogeochemical cycles such as nitrogen or carbon cycling in
hydrothermal systems. Recent work has revealed snapshots of
genetic potential for nitrogen cycling processes in
hydrothermal systems such as nitrogen fixation and
nitrification, and potential correlation with geography and
other physicochemical parameters [for example, 3-6]. As of
yet, no comparison of these processes between terrestrial and
shallow-sea hydrothermal systems has been made.
We surveyed over 100 locations, representing terrestrial
hydrothermal systems in Yellowstone National Park [USA]
and Turkey, and shallow-sea hydrothermal systems in Sicily
[Italy] and Papua New Guinea. In each area, we have
characterized the geochemical environment, energetic
potential, and functional genes diagnostic for stages of the
nitrogen cycle. Our results show that the distribution of nifH
[nitrogen fixation], amoA [nitrification], and narG/nirKS/nosZ
[denitrification] genes differs between samples in sediments
and biofilms. In addition, the genetic potential for nitrogen
cycling is dependent on metabolic zonation within the
hydrothermal system; for example, chemosynthetic vs.
photosynthetic zones. The diversity of nitrogen cycling genes
also varies with the provenace of the sample location, showing
evidence for adaptation.
Multi-proxy ("" 18O, * m , Nd and Pb
isotopes) study for paleoclimate and
paleoweathering in the Maldives area
L. MEYNADIER1, C.J. ALLEGRE1, A.T. GOURLAN1
2
AND F.M. BASSINOT
IPGP (Sorbonne Paris Cité, Université Paris Diderot,
UMR7154 CNRS), 1 rue Jussieu, 75238 Paris Cedex 05,
France
2
LSCE (CNRS/CEA/UVSQ), Domaine du CNRS, 91190 Gifsur-Yvette, France ([email protected], [email protected],
[email protected], [email protected])
1
On the MD900963 sediment archive cored on the edge of
the Maldives Plateau (Equatorial Indian Ocean), we measured
"18O, CaCO3, Magnetic susceptibility (*m), Neodymium and
Lead isotopic compositions of both the ancient seawater and
the detrital fraction. Our analyses cover the last 250 Ka.
The observed variations show fluctuations, which mimics
the glacial-interglacial variations shown by B18O. The two
dominant frequencies are 100 Ka and 23 Ka.
The coherent results of Nd (!Nd) and Pb isotopes on the
detrital fraction and carbonated corrected *m on one hand and
Nd and Pb isotopes of the ancient seawater on the other hand
show without doubt that these variations reflect the regional
weathering and regional sedimentation. These data will also be
in perspective with ODP Site 758 [1] and additional lead
isotopes data from this eastern site.
All together, these results confirm that rain, physical &
chemical erosion were larger during warm periods than during
cold periods. These variations reflect the fluctuations of the
summer monsoon rain intensity. Therefore the study gives
strong limitations for the processes driving the relationship
between climate, rain and weathering in the equatorial Indian
Ocean region over the Glacial/Interglacial alternate.
[1] Gourlan, A. T. L. Meynadier, C. J. Allègre, P. Tapponnier,
J.-L. Birck, & J.-L. Joron (2010) Quaternary Science Reviews,
29(19-20) DOI: 10.1016/j.quascirev.2010.05.003.
[1] Takacs-Vesbach et al. (2008) Env. Micro. 10.
[2] Whittaker et al. (2003) Science 301. [3] Mehta et al.
(2005) Env. Micro. 7. [4] Zhang et al. (2008) AEM 74.
[5] Hamilton et al. (2011). [6] Hall et al. (2008) AEM 74.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Origin of Earth’s volatile elements:
Constraints from Rb isotopes
K. MEZGER1, O. NEBEL2 AND W. VAN WESTRENEN3
Universität Bern, Switzerland ([email protected])
The Australian National University, Canberra, Australia
3
Free University Amsterdam, Amsterdam, The Netherlands
1
2
Compared to the composition of C1-meteorites the Earth
is strongly depleted in volatile elements. This depletions may
be due to incomplete condensation or volatile loss caused by
impact heating during the early stages of the planet formation.
The elemental depletion correlates roughly with the halfcondensation temperatures of the elements. This general
depletion trend for the volatile element abundances in bulk
silicate Earth (BSE) is modified due to core formation which
further fractioned elements based on their siderophile and/or
chalcophile behavior. The combined cosmochemical and
geochemical effects result in the irregular trends observed in
the abundances of the volatile elements in BSE. In order to
separate the different depletion processes that affected the
final composition of BSE we compare the abundances of Rb
and Pb and their isotope compositions in terrestrial samples
and meteorites In order to evaluate the variability of Rb
isotopes in different solar system materials the Rb-isotope
compositions of 17 primitive meteorites and terrestrial
samples was analysed by MC-ICP-MS with Zr as an internal
standard. This technique results in a reproducibility of ± 0.2
‰ for 87Rb/85Rb. The observed variation of the Rb-isotopes in
all materials studied is less than 2 ‰. The variation does not
correlate with the Rb elemental abundances. The
unfractionated Rb-isotopes of the Earth imply that the volatile
element depletion is not due to evaporation or incomplete
condensation alone but requires at least a two step process. A
more realistic model is that the Earth consists primarily of a
large component of essentially volatile free material that was
later mixed with a component that was not depleted in volatile
elements. In this model the Rb-isotope composition of the
mixture is dominated by the isotope composition of the
undepleted component. Mass balancing with a 90% depleted
Proto-Earth and gain of 10% C1 material can account for the
Rb isotope distribution and abundance in the present day BSE.
If Pb behaved approximately like Rb, as is suggested by its
similar half condensation temperature, BSE requires an
additional Pb depletion event to account for its observed U/Pb
and Pb-isotope systematics. Comparison of Rb abundances
and isotopes with Pb abundances and isotopes implies that the
Pb-depletion in the BSE was not solely due to core formation
but most of the Pb was already missing from the Earth prior to
final core mantle equilibration.
Mineralogical Magazine
1461
Simulating experiments on gas
generation of coal under different
fluid pressure
MI JINGKUI, ZHANG SHUICHANG AND HE KUN
Key Laboratory for Petroleum Geochemistry, China National
Petroleum Corporation.
It is still a controversy whether fluid pressure has a
retardation for the hydrocarbon generation of source rock or
not [1-2]. 4 groups experiments of gas generation of coal were
conducted under different fluid pressure (25Mpa, 50Mpa,
75Mpa and 100Mpa) and temperature (300C-650C) in gold
tube closed system. The maximum amount of total
hydrocarbon gas are 102.32ml/g. coal, 95.63ml/g. coal,
122.26ml/g. coal and 124.56 ml/g. coal under 25Mpa, 50Mpa,
75Mpa and 100Mpa, respectively. So, fluid pressure action on
gas generation of coal is not acceleration or retardation
simply, but retardation in a relatively low scope of fluid
pressure, and acceleration for gas generation of coal with fluid
pressure increasing. The amount variation of methane
generated by coal with fluid pressure increasing is consistent
with that of total gases, but the volume variations of other gas
components (such as H2, H2S, CO2) have great difference, this
indicate the influences of fluid pressure on these gases
formation are different.
There is no explicit correlation between the value of &13C1
and the fluid pressure below 430C, the value of &13C1
becomes from light to heavy first, then to light with the fluid
pressure increasing in main period of gas generation (above
470C) in all 4 groups experiments. The more of gas
generating from coal is, the lower of H/C value of coal residue
is. The RO value of pyrolysis residue under 50MPa is lower
than that under others fluid pressure in 470C-575C, in a
point of other range temperature, there is no measurable
difference of residue RO in 4 group experiments
[1] Dalla Torre M. et al. (1997) Org Geochem 61, 2921–2928.
[2] Wei Tao et al. (2010) Fuel 89, 3590–3597.
www.minersoc.org
Goldschmidt Conference Abstracts
1462
Transport of solutes through
hydraulically and chemically
heterogeneous sediments of the
Bengal Basin
Geologic and hydrologic control of
porewater chemistry and submarine
groundwater discharge into Indian
River Bay, Delaware
H.A. MICHAEL
H.A. MICHAEL1*, C. FERNANDEZ1, C.J. RUSSONIELLO1,
A.S. ANDRES2, K.D. KROEGER3, D.E. KRANTZ4,
J.F. BANASZAK4, A. MUSETTO1, K. MYERS1,
L.F. KONIKOW5 AND J.F. BRATTON6
University of Delaware, Newark, DE 19716, USA
([email protected])
The sedimentary history of the Bengal Basin has
determined the structure and pattern of an aquifer system more
than 250, 000 km2 in area and up to 16 km deep. Rivers
carrying huge sediment loads from the Himalayas have
deposited and eroded floodplain sediments through avulsion
cycles; this combined with transgressions and regressions of
sea level have produced complex stratigraphic sequences that
make up a highly heterogeneous hydrogeologic system.
The sedimentary architecture plays a major role in
determining groundwater flowpaths and subsurface transport
of solutes. The depositional history also contributes to
sediment chemistry, which can affect sorptive properties and
other biogeochemical reactions. The effects of hydraulic and
chemical heterogeneity in the Bengal Basin are considered
generally and in two specific contexts: sustainability of
arsenic-safe groundwater resources and groundwater
salinization in the coastal zone.
Widespread contamination of shallow groundwater with
As concentrations above world health standards occurs
throughout much of the lower Bengal Basin, in Bangladesh
and West Bengal, India. High concentrations are limited to the
upper 100m in many areas; thus deep groundwater has been
targeted as a mitigation option. The sustainability of deep
resources depends on hydraulics and chemistry: both
flowpaths and sorption may reduce vulnerability. Simulation
of these protection mechanisms on a regional scale assuming
basin-wide effective properties suggests a sustainable resource
if properly managed. However, small-scale simulations that
incorporate explicit heterogeneity in physical and chemical
properties suggest that As migration may be highly variable,
with short breakthrough times in some areas.
In the coastal zone, groundwater resources are threatened
by salinization, which may become worse as sea level rises in
the future. Currently, fresh groundwater exists at depth
(>~200m) beneath a brackish zone. Mechanisms and
timescales of salinization, both lateral and vertical, were
investigated with variable-density numerical models.
Subsurface salinity distributions, particularly in transient
states, are highly dependent on heterogeneity in hydrogeologic
properties as well as the history of sea level and storm surge
inundations.
Mineralogical Magazine
University of Delaware, Newark, DE 19716, USA
(*correspondence: [email protected])
2
Delaware Geological Survey, Newark, DE 19716, USA
3
U.S. Geological Survey, Woods Hole, MA 02543, USA
4
University of Toledo, Toledo, OH 43606, USA
5
U.S. Geological Survey, Reston, VA 12201, USA
6
NOAA Great Lakes Environmental Research Laboratory,
Ann Arbor, MI 48108, USA
1
Fluxes of nutrients transported by groundwater contribute
to eutrophication in Indian River Bay, Delaware. Fresh and
saline groundwater discharge rates and porewater salinity
depend on system hydrology, mechanisms of groundwaterbaywater exchange, and geologic heterogeneity. The
interactions between these factors produce complex flowpaths
and mixing that may affect nutrient bioavailability by causing
biogeochemical transformations prior to discharge.
The hydrology, stratigraphy, subsurface salinity and Nspecies distributions, and submarine groundwater discharge
(SGD) rates and patterns were characterized at Holts Landing
State Park. A buried paleochannel and near-bottom confining
beds, expected to control both flow and mixing in the
subsurface, were located with offshore chirp seismic profiling
and coring. Electrical resistivity surveys and vertical
porewater salinity profiles to depths of up to 17m indicate that
a zone of freshened groundwater extends hundreds of meters
offshore. Onshore and offshore multi-level wells were
sampled to obtain a 3D distribution of N species in the
subsurface. SGD measurements from Lee-type seepage meters
were collected to better understand discharge salinity, rates,
and spatial and temporal SGD patterns. Measurements
indicate that SGD is primarily saline, and that the lowest
salinity groundwater discharges near the shoreline in the area
away from the paleochannel feature and along the submerged
paleochannel/interfluve boundary. Hydraulic head and
permeability measurements in onshore and offshore wells
provide information on site hydrology and temporal change.
Data were incorporated into a groundwater flow model of the
Indian River Bay watershed, which provides a larger-scale
estimate of groundwater flowpaths and SGD fluxes and
patterns along the entire bay shoreline.
www.minersoc.org
Goldschmidt Conference Abstracts
Chemical composition of lowtemperature biomass ash
M. MICHALIK1*, R. GASEK2,
W. WILCZYDSKA-MICHALIK2
Institute of Geological Sciences, Jagiellonian University, ul.
Oleandry 2a, 30-063 Kraków, Poland
(*correspondence: [email protected])
2
Institute of Geography, Pedagogical University, ul.
Podchor:Eych 2, 30-085 Kraków, Poland
([email protected])
1
The aim of the study of chemical composition of biomass
ash is to evaluate its possible influence on composition of ash
obtained during co-combustion of biomass and coal.
Modification of composition of fly ash by biomass cocombustion with coal often reduce possibility of its utilization.
Environmental impact of biomass combustion is poorly
studied. There is a common opinion that biomass ash does not
contain toxic metals like in the case of coal ash. The study is
based on eight samples of biomass used in power plants in
southern Poland.
Biomass was ashed at 475oC and the yield of ash was from
0.5wt% (sawdust) to 10.8 wt% (olive kernel). Ash is usually
rich in Ca (highest content ca. 16wt% in sawdust ash; content
above 10wt% in three other samples; and the lowest ca.
1.9wt% in bran biomass ash), K (six samples with content
above 10wt%, the lowest value for beechwood biomass), and
P (two samples with content above 5wt% and the lowest
content ca 0.5wt%).
Content of trace elements in studied samples of ash in
often higher comparing with typical coal ash, e.g. Mn from
321 to >10 000 ppm; Ag from 0.02 to 5.3 ppm; Cd from 0.13
to 71.3 ppm; Cr from 3.8 to 988 ppm; Cu from 18 to 588 ppm;
Mo from 2 to 14.7 ppm; Zn 106 to 1923 ppm and Hg from <5
to 35 ppb.
Ash is usually enriched in metals comparing with biomass
samples. Highest enrichment (measured as ratio of content of
element in ash/content of element in biomass) is observed for
sawdust ash (e.g. Mo – 150; Cu - 193; Zn – 196; Ag – 143; Ni
– 91; Co – 287; Mn – 156, Fe - 270; Cd – 230; Bi – 250; Cr –
177; Ba – 198; B – 464).
Obtained results indicate that both the composition of low
temperature biomass ash and degree of enrichment in selected
elements during ashing varies within broad range. Systematic
study is necessary to predict the influence of biomass cocombustion on properties of ash and possible environmental
impact.
Mineralogical Magazine
1463
Evidence for habitable environments
deep in the Martian crust
J.R. MICHALSKI1,2 P.B. NILES3 AND J. CUADROS1
Natural History Museum, South Kensington, London, UK
Planetary Science Institute, Tucson, AZ, USA
(*correspondence: [email protected])
3
NASA Johnson Space Center, Houston, TX, USA
1
2
Observations
Using infrared reflectance spectroscopy and highresolution imaging, we have detected the presence of Fe/Cacarbonates and Fe/Mg-rich phyllosilicates on Mars within
rocks exhumed from deep in the subsurface by meteor impact
[1]. The carbonates occur within layers or bands that are
interbedded with or injected into layered and foliated chlorite,
chlorite-smectite-, pumpellyite-, and possibly serpentinebearing bedrock (Figure 1). This category of deposit is
fundamentally different from previous detections of clay
minerals [2-3] and carbonates [4-5] on Mars because in this
case: a) carbonates and putative hydrothermal phyllosilicates
occur together, b) the materials reflect a subsurface
environment, rather than surface materials, and c) the minerals
occur within rocks that have metamorphic and hydrothermal
textures.
Implications
The carbonate- and clay-bearing rocks observed within
Leighton Crater were excavated from ~6 km depth. These
rocks may represent some of the most ancient sedimentary
rocks on Mars (also in the Solar System) that were
subsequently buried and metamorphosed. Alternatively, they
may be evidence for deep-seated hydrothermal activity in a
habitable subsurface environment.
Figure 1: A HiRISE image of the central peak of Leighton
Crater, Mars, where carbonates are detected within light-toned
rocks that occur within exhumed, phyllosilicate-rich bedrock.
Arrows point to a fault that offsets carbonates.
[1] Michalski & Niles (2010) Nature Geo. 3, 751–755.
[2] Bibring et al. (2006) Science 312, 400–404. [3] Murchie et
al. (2009) J. Geophys. Res. 114, 1–30. [4] Ehlmann et al.
(2008) Science 322, 1828–1832. [5] Morris et al. (2010)
Science 329, 421–424.
www.minersoc.org
1464
Goldschmidt Conference Abstracts
Geochemical and geophysical
coupling study of the karstic aquifer
between Saïs Basin and the Causses
of the Middle Atlas (Morocco). FezMeknès area
HÉLÈNE MICHE1, ADRIANO MAYER1,
GINETTE SARACCO1, MOHAMED ROUAI2,
ABDELILAH DEKAYIR2, KONSTANTINOS CHALIKAKIS3
3
AND CHRISTOPHE EMBLANCH
CNRS-UMR6635, CEREGE, UPCAM, Europole de l'Arbois,
BP 80, F-13545 Aix en Provence, France
(*correspondence: [email protected])
2
Université M. Ismail, Département de Géologie, Quartier
Zitoune, Meknès, Marocco
3
EMMAH (UAPV, INRA) CNRS-UMR_A 1114, 33 rue
pasteur, 84000, Avignon, France
1
The population growth in the region of Fez-Meknès (1.6
Million), accentuated by the increasing number of wells for
agriculture, and by the increasing aridity in recent years, poses
the problem of controlling water of sufficient quality and
quantity over time.
This fractured karstic Basin mainly composed of Liassic
dolomitic limestones overlying Triassic basalts, shales and
evaporites, is the main drinking water supply in the region.
The karstic reservoir presents a decline in its chemical quality
and ponctually some turbidity problems.
To better understand this system and the interactions
between different aquifers and aquitards, we conducted
coupling study on:
i) geochemistry (major and minor elements, "18O, "D and
222
Rn) of the main springs of Liassic and Triassic origin that
could be connected each other and with the major spring of
Bittit;
ii) electromagnetic multi-scale tomography for separating
draining faults from not draining faults (geological structure).
The geochemistry of water during the three surveys in
2009 and 2010 shows a major Liassic origin for Bittit, Ribaa,
Aguemguam, Amansayarmine, Bou Youssef and El Hajeb
springs, and a major Triassic origin for El Mir, Sbaa 2,
Maarouf1 and Maarouf2 springs. Radon 222 (T=3.85days) has
highlighted the existence of areas of rapid exchange between
waters of Liassic aquifers characterized by low Radon activity
(3500 Bq/m3) and waters of Triassic aquitards characterized
by a high Radon activity (> 12000 Bq/m3). The transit time
from the Triassic aquifer is less than two weeks. Analyses of
"18O versus "D show only a slight excess of Deuterium, this
characterizes a local recharge of the groundwater.
Geophysical measurements of resistivity and conductivity
show anomalies in the direction of Bittit and perpendicularly
to the Causses, confirming the presence of a preferential
drainage where Liassic waters of high quality mix with those
in contact with the Triassic aquitard.
Acknowledgment: These studies are funded by the CNRS,
Program of the Fédération de Recherche ECCOREV, and the
Conseil Régional PACA, BREMEX Program.
Mineralogical Magazine
Natural ferrihydrite: Impact of
structure and composition on redox
cycling
F.M. MICHEL1,2, A.C. CISMASU1, J.S. LEZAMA2,
M. MASSEY1, S. FENDORF3, G.E. BROWN, JR.1,2
2
AND J.R. BARGAR
Geological & Environmental Sciences, Stanford University,
Stanford, CA 94305, USA
2
SLAC National Accelerator Laboratory, Menlo Park, CA
94025, USA
3
Department of Environmental Earth System Science,
Stanford University, Stanford, CA 94305, USA
1
Synthetic ferrihydrite (Fh) is typically used in laboratory
studies and in the field, to a lesser extent, as a model
compound for natural Fh in terms of understanding its sorption
capacity, reactivity, stability, and dissolution and
transformation behavior. All are properties that make naturally
occuring Fh one of the most important natural Fe (III)
oxyhydroxides in geochemical systems undergoing
biogeochemical cycling of iron and redox-active contaminant
metals such as U.Although much is known about synthetic Fh,
recent research by our group calls into questions its relevance
to natural systems. Many past studies have suggested that
natural Fh often contains a suite of impurities (e.g. Zn2+, Cr3+,
Al3+, silicate, phosphate, organic carbon complexes) that can
range widely depending on the conditions of Fh formation. It
is less clear, however, how impurities impact the bulk and
surface structure of Fh and its reactivity and stability. Our
recent work [1] on natural Fh formed in an acid mine drainage
system demonstrated that impurities, mainly Al, Si, and
natural organic matter, increased structural disorder and
decreased average particle size. Such details are important as
they are likely to have significant impact on the
biogeochemical reactivity of Fh.
While our picture of synthetic Fh structure continues to
improve, little is known about the individual and cumulative
effects of structural disorder (e.g. lattice strain and cationic
vacancies), size, and composition on electron transfer
processes occurring in Fh under reducing conditions.
Processes related to the Fe (II)-induced reductive
transformation are important, for example, because of the
potential for environmental contaminants such as uranium to
be directly incorporated in Fh transformation products. Our
current work aims to better understand the links between the
structure/composition and biogeochemical reactivity for both
natural Fh and synthetic analogues to natural samples.
[1] Cismasu et al. (2011) Comptes Rendus Geosci. In press.
www.minersoc.org
Goldschmidt Conference Abstracts
Oxygen and hydrogen stable isotope
composition of precipitation in FriuliVenezia Giulia (Northeastern Italy)
M. MICHELINI*, F. CUCCHI, O. FLORA, B. STENNI,
F. TREU AND L. ZINI
Department of Geosciences, University of Trieste, Italy
(*correspondence: [email protected])
Introduction
Oxygen and hydrogen stable isotopes, being natural
tracers of the hydrological cycle, have been extensively used
as tools to characterize regional aquifers. In particular, the
knowledge of the mean annual-weighted isotopic composition
of precipitation is a very important tool to determine the origin
of the waters that feed aquifers and rivers, their recharge area
and its mean altitude, thanks to the definition of the vertical
isotope gradient. The knowledge of the relationship between
isotopic composition of local precipitation and local
environmental conditions is also essential for hydrological
studies. In order to provide an overview of the isotopic
composition of the precipitation in Friuli-Venezia Giulia
region a monitoring of the regional rain gauge network has
been carried out at the University of Trieste from 2004 to
2010.
Results and Discussion
Here we present "18O data obtained from monthly
precipitation collected by rain gauges; where possible the "18O
data were compared with temperature data weighted for
precipitation (fig. 1) showing generally a good correlation.
Vertical "18O gradients for homogenuos areas and an average
gradient for the region as a whole were also calculated.
Finally the local meteoric water line was calculated using "18O
and "D long-term weighted values for all the sampling sites.
Figure 1: Monthly trends of "18O and temperature for the
Tarvisio sampling site.
1465
Metastable accessory phases in high
heat-producing felsic igneous rocks
A.W. MIDDLETON*, S.D. GOLDING AND I.T. UYSAL
University of Queensland, St. Lucia, QLD 4066, Australia
(*correspondence:
[email protected])
High heat-producing felsic igneous rocks are characterised
by enriched values of U, Th and K relative to upper
continental crust, and are of specific interest when seeking to
exploit geothermal energy through enhanced geothermal
systems. The elevated values reflect the evolved nature of the
felsic rock; common examples include granites and rhyolites.
The current study focuses on famous HHP systems of Soultzsous-Forêts, France, Cornwall, UK, and the novel HHP
rhyolite of central Queensland, Australia.
Samples from Soultz and central Queensland show
evidence that metasomatised titanite can form rutile + calcite
+ quartz with accessory hydrothermal zircon and Ca (REE,
Y)CO3 (OH, F)? or cheralite, respectively. The accessory
phases reflect how Zr, Th, Y and REE can substitute into
titanite’s structure in an evolved system. EPMA of the
anhedral hydroxyl-, fluoro-carbonate phase found elevated
values of both Ca and Ce with variable LREE, Y and Th. The
occurrence of Ca (REE, Y)CO3 (OH, F)? in place of cheralite
may result from elevated [CO2] and [F-] as opposed to [PO43-]
and [CO2]; as indicated by cogenetic chloritisation of Fbearing biotite and intercleavage-grown ankerite. Mobilisation
of incompatible elements as fluoro-carbonate ligand
complexes was minimised by the presence of Ca2+, resulting in
precipitation within or proximal to the titanite void. By
contrast, SEM analyses of the F--dominated Cornish
metasomatic system shows monazite solid-solution phases
along cleavage planes of chloritised biotite, implicating the
uncommon mobilisation of Th4+. Further EMPA will better
define these phases and constrain their palaeometasomatic
conditions.
Analysed primary accessory phases such as titanite were
relatively enriched in incompatible elements that formed
polyminerallic assemblages following metasomatism. The
volatile content of metasomatising fluids played a significant
role in the production of these metastable phases. Titanite
specifically, destabilised in the presence of CO2 or F- [1, 2].
Volatiles not only helped destabilise the primary phases but
also mobilised constituent elements; as seen when halide
ligands drastically increase the mobility of incompatible
elements such as REE and HFSE [3]. By analysing metastable
accessory phases, this study will further constrain under which
conditions HHP systems undergo metasomatism as well as
better understand the extent of metasomatic incompatible
element immobility.
[1] Markl & Piazolo (1991) Am. Min. 84, 37–47. [2] Hunt &
Kerrick (1977) G&C Acta 41, 279–288. [3] Wood (1990)
Chem. Geo. 88, 99–125.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
1466
An experimental study of the stability
of hydrosulfide species of Fe(II) at
hydrothermal conditions
Isotope-geochemical features of
enriched mantle source of rift
tholeiites from Bouvet Triple
Junction (South Atlantic)
ART. MIGDISOV1*, D. ZEZIN2
1
AND A.E. WILLIAMS-JONES
Earth & Planet. Sci., McGill Univ., Montreal, H3A 2A7
Canada (*correspondence: [email protected])
2
Institute of Geochemistry and Petrology, ETH Zurich, CH8902 Zurich, Switzerland
NATALIA A. MIGDISOVA1*,
NADEZHDA M. SUSHCHEVSKAYA1
2
AND BORIS V. BELYATSKY
1
Iron is one of the most abundant elements in the Earth’s
crust, and is actively involved in the processes of
hydrothermal alteration and ore mineralisation. Iron-bearing
sulphides dominate most hydrothermal sulphide ore bodies
and form in a wide variety of geological environments at
conditions ranging from those of magmatic intrusions to those
of sediments undergoing diagenesis. However, our knowledge
of the speciation of this metal in sulphide-bearing fluids is
surprisingly limited. Despite the participation of iron in
processes involving reduced sulphur-bearing fluids, the
behaviour of the hydrosulphide species of this metal is
effectively unknown at elevated temperature. Partly because
of this, the hydrothermal transport and deposition of iron is
commonly modelled exclusively using chloride species. The
goal of our study was therefore to determine stability constants
for hydrosulfide complexes of Fe (II) experimentally at
temperatures up to 350-400 °C, and to evaluate the
contribution of these complexes to the mobilisation of iron in
nature.
Our experiments were performed in light-weight titanium
autoclaves and involved measurement of the solubility of
pyrite (FeS2) in acidic solutions (pH<3) saturated with respect
to H2S at partial pressures of this gas varying from 15 to 120
bars. The acidity of the solutions was controlled using HClO4
for experiments at T8250 °C, and HCl at higher temperature.
After equilibrium was attained, the autoclaves were quenched,
pyrite was removed, and samples of the quenched solutions
were analysed for Fe and Cl. Precipitates that formed during
quenching were dissolved by washing the autoclaves with
HCl; the washing solutions were also analysed for Fe. All
analyses were performed using NAA.
The data obtained in our study suggest that, at
temperatures up to 300 °C, the dominant hydrosulphide
species of iron are FeHS+ and Fe (HS)2°. They also suggest
that the concentration of these species is sufficient for them to
play an important role in the transport and deposition of Fe (II)
in H2S-rich hydrothermal systems.
Mineralogical Magazine
Vernasky Institute of Geochemistry RAS, Moscow, Russian
Federation (*correspondence: [email protected])
2
VNIIOkeanologia, Antarctic Geology, St.Petersburg, Russian
Federation ([email protected])
1
Bouvet triple junction (BTJ) is formed by three spreading
ridges: Mid-Atlantic (MAR), American-Antarctic (AAR),
South-West Indian (SWIR) and is marked by especially
complicated construction and evolution. The isotopic analysis
of glasses from the Spiess Ridge and Bouvet segment of
SWIR revealed the relatively high 206Pb/204Pb (18.4 to 19.2)
and low 143Nd/144Nd values (0.512603-0.513103) indicating
the source enrichment compared to the depleted oceanic
mantle [1]. Differences in 207Pb/204Pb vs 206Pb/204Pb contents in
tholeiites from BTJ region and adjacent structures imply
diverse magmatic sources. We assume that type of enrichment
of BTJ mantle source is like HIMU and is close to those of
lamprophyres from Antarctic Ferrar province formed during
the Karroo - Ferrar plume influence about 180 m. y. ago [2].
Pyroxenite component in parental source was established by
olivine composition [3] and generally constituted about 30-40
% of parental melts [3, 4].
One of the plausible explanations of so considerable
amount of the ancient substance is the formation of the west
end of SWIR over some crustal blocks which were separated
during/ after Gondwana breakup. These microplates could
comprise parts of a pre-existing retro-arc fold thrust belt [5].
[1] Hauri & Hart (1994) J. Geophys. Res. 99, 24301–24321.
[2] Riley et al. (2003) Lithos 66, 63–76. [3] Sobolev et al.
(2007) Science 316, 412–417. 112. [4] Migdisova et al. (2009)
Alpine Ophiolites & Modern Analogues, Continental rifting to
oceanic lithosphere, insights from the Alpine ophiolites &
modern oceans. Abstract volume, 47. [5] Martin (2009) USGS
OF-2007-1047, Extended Abstract 112.
www.minersoc.org
Goldschmidt Conference Abstracts
Cu isotope geochemistry in the
unusual Las Cruces supergene
copper deposit
N.G. MIGUELEZ1*, R. MATHUR2, F. TORNOS1,
F. VELASCO3 AND J.C. VIDEIRA4
IGME, Rios Rosas, 23. 28003, Madrid, Spain & UNIA,
21819 La Rábida, Huelva, Spain ([email protected])
(*correspondence: [email protected])
2
Juniata College, Department of Geology, Huntingdon, PA
16652, USA ([email protected])
3
Universidad del País Vasco, Apdo. 644, 48080 Bilbao, Spain
([email protected])
4
Cobre Las Cruces, S.A., 41860, Gerena,, Sevilla, Spain
([email protected])
1
The Las Cruces deposit (17 Mt @ 6.7% Cu) is the last ongoing mine of the Iberian Pyrite Belt (IPB). The ore deposit
consists of an unusual supergene copper enrichment zone of a
common late Devonian VMS. This is located below the
Guadalquivir river Basin, which hosts an aquifer on its base
that is still interacting with the deposit nowadays. Late Alpine
faults crosscut the deposit and act as fluid pathways related to
the latest enrichment process; thus, three Cu-sulphides
generations are identified: granular non-cemented Cusulphides formed during the weathering process, chalcocite
related to late calcite-quartz veins, and euhedral chalcocite
crystals grown over calcite veins. Textures and isotope
geochemistry suggest a critical influence of microbial activity
during the enrichment processes.
The primary sulphides show enrichment on &65Cu
(1.96±0.70‰) in comparison to other primary sulphides
worldwide [1]. The secondary Cu-sulphides are largely
depleted on &65Cu and they show consecutively steeply
enrichment on &65Cu in the three Cu-sulphides mineralization
generations: &65Cu=-6.39±0.10‰ in granular non-cemented
Cu-sulphides, &65Cu= -5.36±0.19‰, in chalcocite related to
late calcite-quartz veins and &65Cu= -3.77±0.17‰ in euhedral
chalcocite crystals. These would show the three steps of the
evolution of a mineralizing fluid, which is also enhanced by
biogenic activity [2]. Finally, the gossan samples show a very
large variation in &65Cu, including both positive and negative
values (&65Cu= -7.79‰ & 3.84‰).
The &65Cu composition of the Las Cruces ore deposit
present unusual values in comparison with studies developed
on other VMS and gossan related.
1467
The nanoscale structure of complex
perovskite-type oxides with superb
dielectric properties
BORIANA MIHAILOVA
Mineralogisch-Petrogrpahisches Institut, Universität
Hamburg, Grindelallee 48, 20146 Hamburg, Germany,
email: [email protected]
The perovksite (ABO3) structure type is an outstanding
example of how chemical variations can tune the nanoscale
atomic arrangements and thus influence the properties of
complex oxide materials. Thanks to V. M. Goldschmidt who
formulated the relation between the chemical composition and
the structural stability, the perovksite-type crystals are
nowadays key functional materials used in a number of
technological applications. Pb-based relaxors are advanced
ferroelectrics with remarkable dielectric, electromechanical
and electrooptic responses. The exceptional properties of
relaxors are due to their structural inhomogeneities. At
ambient conditions, the average structure is pseudocubic but
rich in ferroic nanoregions too small to be directly studied by
conventional diffraction analysis. However, combining in situ
temperature and pressure diffraction and Raman scattering
allows us to resolve the structural complexity of relaxors. Due
to the different length and time scales of sensitivity,
diffraction probes the long-range order, i.e. the structure
averaged over time and space, while Raman spectroscopy can
detect local structural deviations from the average structure
via the anomalous Raman activity of the phonon modes that,
when the symmetry of the average structure is considered,
should not generate Raman peaks. Hence, the combined
analysis of the long-range order induced at low temperatures
or high pressures and of the phonon anomalies enhanced on
temperature decrease or pressure increase can reveal the
energetically preferred structural nanoclusters existing at
ambient conditions. The structural analysis of series of model
compounds, namely stoichiometric and A-site doped (Ba2+,
Bi3+, La3+, Sr2+) PbSc0.5Ta0.5O3 and PbSc0.5Na0.5O3 as well as
solid solutions with three cationic types on the B-site showed
that at ambient conditions, on the mesoscopic scale, polar
order coexists with antiferrodistortive order, which may be the
key reason for the relaxor behaviour. Chemically-induced
local elastic fields influence the nanoscale atomic clustering
more strongly than chemically-induced local electric fields do.
[1] Larson et al. (2003) Chem. Geol. 201, 337–350.
[2] Mathur et al. (2005) Geochim. Cosmochim. Acta 69, 5233–
5246.
Mineralogical Magazine
www.minersoc.org
1468
Goldschmidt Conference Abstracts
Dissolution kinetics of Pd and Pt
from automobile catalysts by
naturally occurring complexing
agents
MARTIN MIHALJEVI#1, OND"EJ 'EBEK2,
LADISLAV STRNAD2, VOJTFCH ETTLER1, JOSEF JEGEK3,
ROBIN 'TEDRH1 AND PETR DRAHOTA1
Institute of Geochemistry, Mineralogy and Mineral
Resources, Charles University in Prague, Albertov 6, CZ128 43 Prague 2, Czech Republic
2
Laboratories of the Geological Institutes, Charles University
in Prague, Albertov 6, CZ-128 43 Prague 2, Czech
Republic
3
Institute of Applications of Mathematics and Information
Technologies, Charles University in Prague, Faculty of
Science, Albertov 6, CZ-128 43 Praha 2, Czech Republic
1
Powder samples prepared from gasoline (Pt, Pd, Rh, new
GN/old GO) and diesel (Pt, new DN/old DO) catalysts and
recycled catalyst NIST 2556 were tested by kinetic leaching
experiments following 1, 12, 24, 48, 168, 360, 720 and 1440hour interaction with solutions of 20 mM citric acid (CA), 20
mM Na2P4O7 (NaPyr), 1 g L-1 NaCl (NaCl) and a fulvic acid
solution (FA- DOC 50 mg L-1). The mobilization of Pt metals
into solution was fastest through the effect of CA and NaPyr.
In the other interactions (NaCl, FA), the release of PGE is
probably followed by immobilization processes and the
interactions cannot be considered to correspond to simple
release of Pt metals into solution. Because of their low
concentrations, the individual complexing agents did not have
any effect on the speciation of Pd and Pt in the extracts; both
metals are present in solution as complexes (Me (OH)2, Me
(OH)+). Immobilization can take place through the adsorption
of the positively charged hydroxyl complexes or flocculation
of fulvic acid complexing the Pt metals on the surface of the
extracted catalysts. The calculated normalized bulk released
NRi values are similar to the reaction rate, highest in solutions
of CA and NaPyr.
Mineralogical Magazine
Sr/86Sr isotope ratios in single
benthic foraminifera by LA-MCICPMS
87
TAMÁS MIKES1,2*, AXEL GERDES2,
NATÁLIA HUDÁ%KOVÁ3 AND ANDREAS MULCH1,2
Biodiversity and Climate Research Centre (BiK-F), Frankfurt
am Main, Germany
2
Institute of Geosciences, Goethe University, Frankfurt am
Main, Germany
(*correspondence: [email protected])
3
Department of Geology and Palaeontology, Comenius
University, Bratislava, Slovakia.
1
Sr/86Sr analysis of foraminifera is usually performed
from solution samples using either TIMS or MC-ICPMS
techniques. With increasing precision offered by recent
advances of laser ablation instrumentation, the LA-MCICPMS approach rivals solution work in terms of precision,
and outperforms conventional solution techniques in terms of
sample throughput and time needed per analysis.
Within an ongoing paleoclimatic study, we have
determined 87Sr/86Sr isotope ratios from single tests of the
benthic foraminifera Quinqueloculina sp. from a Neogene
hyperhaline paralic sequence in Central Anatolia, Turkey. The
analytical setup used consists of a RESOlution M-50 excimer
LA instrument (&=193 nm) including a factory-built Laurin
two-volume sample cell, coupled to a Thermo Neptune MCICPMS. During 60 seconds of data acquisition a 200-300 µm
long line was ablated (8 Hz, 3.5 J/cm2) with pit diameter
varying between 53 to 140 µm. After correction for
interferences from Rb, Kr, Ca-dimers and doubly-charged
REE, all Sr isotope data were corrected for mass fractionation
(86Sr/88Sr = 0.1194) and normalized to NIST SRM987 using
87
Sr/86Sr of 0.71025. Repeated measurements on a recent coral
from the Red Sea (~3000 ppm Sr) yielded 87Sr/86Sr ratios of
0.709235 ± 0.000023 (2$ s. d.).
For the Quinqueloculina sp. tests, pit diameter were
adjusted to 80 or 120 µm and the ablation path was located at
the topmost part of the curved, quasi-globular test surface.
87
Sr/86Sr ratios cover a range from 0.707174 ± 0.000032 to
0.707255 ± 0.000027, with calculated net reproducibilities
being in the range of as low as ±0.00004 (2$ s. d.).
Overall, the LA-based analysis of 87Sr/86Sr in foraminifera
is likely most suitable in cases where low sample amounts
(e.g. high-resolution stratigraphic work on drillcores) and/or
high sample numbers are dealt with; i.e. for material otherwise
not providing the necessary Sr concentration in the final
solution, or requiring time-consuming Sr separation and
solution work.
87
www.minersoc.org
Goldschmidt Conference Abstracts
The abiogenic generation of low !13C
reservoirs in the deep Earth
S. MIKHAIL1,2*, A. SHAHAR3, S.A. HUNT1,
A.B. VERCHOVSKY2, I.A. FRANCHI2, S, BASU1
1
AND A.P. JONES
Department of Earth Sciences, UCL, Gower Street, London,
WC1E 6BT, UK (*correspondence: [email protected])
2
PSSRI, The Open University, Walton Hall, Milton Keynes,
UK
3
Geophysical Laboratory, Carnegie Institution of Washington,
Broad Branch road, Washington, DC 20015, USA
1
The stable isotopes of carbon from mantle diamonds
(expressed as &13C) provide a direct proxy used to understand
the Earth’s deep carbon cycle (carbon speciation, reservoir
identification and exchanges between such reservoirs). Carbon
speciation is highly dependent upon the local fO2 and
variations of this parameter in an open system can result in
isotopic fractionation of carbon where two species are stable
and one is mobilised and removed [1]. The largest measured
fractionation factor in nature for 13C under mantle conditions
is between graphite and Fe-carbide (circa +12 ‰) [2] and at a
higher temperature between diamond and Fe-carbide (circa +7
‰) [3]. This system may have a large impact on the BSE deep
carbon cycle and if not considered, and well quantified, may
cause significant errors in the interpretation of low &13C values
determined from terrestrial and extra-terrestrial mantle
samples. This system requires fO2 conditions to be lower than
the IW buffer and also requires the presence of FeO. Frost et
al. [4] provided experimental evidence for the stability and
predicted existence of FeO with magnesium silicate perovskite
and ferropericlase in the lower mantle. More recently
Rohrbach et al. [5] demonstrated that from depths < 250 km,
the upper mantle can also host stable FeO with subcalcic
pyroxene and majoritic garnet buffering the fO2 to IW -2.
Therefore it is plausible that two solid phases of carbon could
be stable; diamond and Fe-carbide. We present new data for a
measured fractionation factor between natural and synthetic
diamond and Fe-carbide samples and place constraints upon
the P-T effects of 13C fractionation from 2-25 GPa and 142000 K in the system Fe-C. This data probes conventional
ideas surrounding the modelling of 13C fractionation during
mantle-core differentiation, geodynamic cycling of carbon as
inferred using empirical data from mantle xenoliths and
xenocrysts and the nature and source (abiogenic vs. biogenic)
of low &13C values determined from terrestrial and extraterrestrial mantle samples.
Kirschsteinite exsolution lamellae in
olivine from young angrites:
Implications for their thermal history
T. MIKOUCHI1*, M. MIYAMOTO1 AND G.A. MCKAY2
Dept. Earth & Planet. Sci., Univ. of Tokyo, Tokyo 113-0033,
Japan (*correspondence: [email protected])
2
NASA-JSC, Houston, TX 77058, USA (deceased)
1
Angrites are among the oldest known basaltic rocks in the
solar system characterized by unique mineralogy and
chemistry. They can be mainly divided into two subgroups by
difference in texture and crystallization ages (~4564 Ma
‘quenched’ angrites and ~4558 Ma ‘plutonic’ angrites) [e.g.
1]. Among them, young plutonic angrites are important to
understand prolonged igneous activity in the angrite parent
body (APB), and understanding of their geological settings
can offer good information about the crustal evolution of
APB. Kirschsteinite exsolution lamellae present in olivine
from LEW86010 (LEW) plutonic angrite could be used to
estimate its cooling rate and burial depth by calculating Ca
diffusion profiles [2]. Similar exsolution was found in recently
discovered plutonic angrite NWA4590 (NWA) [3], and we
performed the same calculation. The obtained cooling rate of
NWA olivine is 0.15 oC/year, corresponding to the burial
depth of 240 m. This cooling rate is ~1 order of magnitude
slower than that of LEW (1.7 oC/year: 75 m depth [2]). The
lamella growth in NWA was from 975 to 700 oC, and the
LEW lamellae grew in a similar temperature range (1000-700
o
C) [2, 4]. Amelin et al. [5] obtained a cooling rate of 540±290
o
C/Ma for NWA by using the Pb-Pb age difference of
pyroxene and silico-apatite. This cooling rate is too slow and
will homogenize pyroxene zoning observed in NWA, and thus
the age difference is unrelated to cooling as also suggested by
[5]. A geological setting for the 75~240 m depth might be in a
lava lake or hypabyssal intrusion. Although LEW and NWA
share similar mineralogy and crystallization ages [1, 2, 5],
their cosmic-ray exposure ages are different [6], suggesting
sampling from different regions of APB. If this is the case, a
rock unit with the lithology similar to LEW and NWA may
show wide and deep spatial distribution in the crust of APB.
[1] Amelin (2008) GCA 72, 221–232. [2] McKay et al. (1998)
MAPS 33, 977–983. [3] Kuehner & Irving (2007) LPSC
XXXVIII, #1522. [4] Davidson & Mukhopadhyay (1984)
Contrib. Mineral. Petrol. 86, 256–263. [5] Amelin et al.
(2011) LPSC XLII, #1682. [6] Nakashima D. et al. (2008)
MAPS 43, Suppl. A112.
[1] Cartigny et al. (1998) Science 280, 1421. [2] Deines &
Wickman (1975) GCA 39, 547. [3] Mikhail et al. (2010) AGU
Abstract [4] Frost et al. (2004) Nature 428, 6981.
[5] Rohrbach et al. (2010) J. Petrol 52, 717-731.
Mineralogical Magazine
1469
www.minersoc.org
1470
Goldschmidt Conference Abstracts
Evaluation of matrix effects during
laser ablation MC ICP-MS analysis
of boron isotopes in tourmaline
JITKA MÍKOVÁ1,2*, JAN KO'LER2
3
AND MICHAEL WIEDENBECK
Czech Geological Survey, Klárov 3, Prague 1, CZ-118 21,
Czech Republic
(*correspondence: [email protected])
2
Centre for Geobiology and Department of Earth Science,
University of Bergen, Allegaten 41, Bergen, N-5007,
Norway
3
Helmholtz Centre Potsdam, GFZm German Research Centre
for Geosciences, Telegrafenberg, 14473 Potsdam,
Germany
1
This study evaluates the effects of laser ablation ICP-MS
instrument parameters and sample matrix composition on data
accuracy and precision. Laser ablation MC ICP-MS was used
to determine boron isotopic compositions of several natural
tourmaline group minerals with variable chemical
composition. Some of the studied samples have been
previously used as reference materials for in situ isotopic
analysis (98144 elbaite [1, 2], 108796 dravite [1, 2], 112566
schorl [1, 2] and B4 [3]). The choice of laser and ICP-MS
instrument parameters has a significant effect on the measured
11
B/10B ratios, namely as a result of different signal intensities
and 40Ar4+ spectral interferes on the 10B mass peak. This
interference can be suppressed by optimizing mass resolution
of the instrument. Laser induced isotopic fractionation of B
was negligible for single laser spot and laser raster sampling
strategies, allowing for a choice of an optimal sampling mode
depending on the size, shape and homogeneity of the sample.
It can be demonstrated that the tourmaline matrix affects
significantly the obtained #11B values and impacts on data
accuracy, especially if a non matrix-matched reference
material is used for calibration. In case of matrix-matched
calibration, the accuracy of LA MC ICP-MS boron isotopic
data is comparable to the previously published values obtained
by TIMS technique. The measurement precisions associated
with the average "11B values achieved by LA MC ICP-MS are
between 0.2 and 0.5‰ (1 s).
[1] M.D. Dyar et al. (2001) Geostand. Newsl. 25(2-3), 441–
463. [2] W.P. Leeman, S. Tonarini (2001) Geostand. Newsl.
25(2-3), 399–403. [3] Tonarini et al. (2003) Geostand. Newsl.
27, 21–39.
Re-Os age of molybdenite from the
Tatra Mountains, Poland
S.Z. MIKULSKI1, A. GAWIDA2 AND H.J. STEIN3,4
Dept. of Mineral Deposits Geology, Polish Geological
Institute - National Research Institute, Warsaw, Poland
(stanislaw.mikulski @pgi.gov.pl)
2
Faculty of Earth Sciences, University of Silesia, 41-200
Sosnowiec, Poland ([email protected]
3
AIRIE Program, Colorado State University, USA
([email protected])
4
Norges Geologiske Undersøkelse, 7491 Trondheim, Norway
1
The Tatra Mountains are a tectonically uplifted piece of
Variscan crust emplaced during the Alpine orogeny and
forming part of the Central Western Carpathians. Mesozoic
sedimentary formations overlie a pre-Alpine core composed of
a polygenetic granitoid intrusion and its metamorphic
envelope, extensively migmatized [1]. The contact zone of
metamorphic rocks and hybrid granite [2] is well exposed in
the western part, called Western Tatra Mts.Textural,
geochemical, and isotopic studies point to a mixed I- and Stype character for the Tatra granitoid intrusion, formed by
multiple magma batches in the age interval 370–345 Ma [2, 3,
5]. The polygenetic granitoid intrusion, defined as a tongueshaped, tabular body [4], is concordant with regional
metamorphic foliation.
Molybdenite was collected from the northern debris slope
(ca. 1580 m a. s. l.) below the Wo<owiec peak. Molybdenite is
observed as single isolated blades (<3 mm) or small
aggregates of crystals (<5 mm in diameter) in pegmatite,
within a coarse-grained leucocratic porphyritic granite.
Molybdenite is associated with K-feldspar, albite, quartz and
coarse-grained muscovite. In this area the local brecciation of
the granite and its envelope by boron-rich fluid is observed.
The analyzed molybdenite sample has a Re concentration
of 16.58 ± 0.01 ppm, and an 187Os concentration of 61.04 ± 5
ppb, providing a 187Re-187Os model age of 350 ± 1 Ma
indicating a period of molybdenite crystallization in
Carboniferous Lower Missisippian (Tournaisian) and is in
accordance (within brackets) with WR Rb-Sr isotopic age of
pegmatites and U-Pb dating of magmatic zircons [6]. We
suggest molybdenite crystallized from fluids locally derived
from the hosting coarse-grained leucocratic granite. This is the
first report on the presence of molybdenite in the Tatra Mts.
and its age can be interpreted as the timing of fluid exsolution
from the cooling granite.
This work was financially supported by Polish Ministry of
Science and Higher Education, Grant N N 525 393739.
[1] Burda & Gaw;da (2009) Lithos 110, 373–385. [2] Burda et
al. (2011) Mineralogy & Petrology (in print). [3] Gaw;da
(2008) Geol. Carpathica 59, 4, 295–306. [4] Kohut & Janak
(1994) Geol. Carpathica 45, 5, 301–311. [5] Poller et al.
(2000) Inter. Jour. Earth Sci. 89, 336–349. [6] Gaw;da (1995)
Geol. Carpathica 46, 2, 95–99.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Linking structural isomerism of
organic ligands to the precipitation
and structure of ferrihydrite
C. MIKUTTA
Institute of Biogeochemistry and Pollutant Dynamics , ETH
Zurich, Switzerland ([email protected])
The extent of interference of organic ligands with the
polymerization of Fe(III) has not been systematically studied
as a function of structural ligand properties. Here I tested how
the number and relative phenol group positions in
hydroxybenzoic acids affect both ferrihydrite formation and its
local (<5 Å) Fe coordination. To this end, acid Fe(III) nitrate
solutions were neutralized up to pH 6.0 in the presence of
increasing concentrations of 4-hydroxybenzoic acid (4HB),
and the two constitutional isomers 2,4-dihydroxybenzoic acid
(2,4DHB) and 3,4-dihydroxybenzoic acid (3,4DHB). The
precipitates formed were dialyzed, lyophilized, and
subsequently studied by means of X-ray absorption
spectroscopy and synchrotron X-ray diffraction.
The solids contained up to 32 wt% organic C. Only
precipitates formed in 3,4DHB solutions comprised significant
Fe(II) (Fe(II)/Fetot 86 mol%), implying the abiotic
mineralization of the catechol-group bearing ligand during Fe
(III) hydrolysis under oxic conditions. Ferrihydrite formation
was significantly impaired by the ligands (4HB ~ 2,4DHB <<
3,4DHB). Coordination numbers of edge- and corner-sharing
Fe in the precipitates decreased with increasing initial ligand
concentration by up to 100%. Linear combination fitting
(LCF) of Fe K-edge X-ray absorption near edge structure
(XANES) and extended X-ray absorption fine structure
(EXAFS) spectra, however, revealed that these decreases were
due to increasing proportions of organic Fe(III) complexes.
All ligands reduced the coherently scattering domain (CSD)
size of ferrihydrite as indicated by synchrotron X-ray
diffraction analysis (4HB < 2,4DHB << 3,4DHB). With
decreasing particle size of ferrihydrite its Fe(O,OH)6 octahedra
became progressively distorted as evidenced by an increasing
loss of centrosymmetry of the Fe sites. Pre-edge peak analysis
of the Fe K-edge XANES spectra in conjunction with LCF
results implied that ferrihydrite contains 11 ± 2% tetrahedral
Fe(III).
The results suggest that especially hydroquinone moieties
of NOM effectively suppress Fe(III) polymerization and
ferrihydrite formation. Organic chelates seem to control
ferrihydrite formation mainly by kinetically modulating the
availability of Fe(III) for nucleation and/or polymerization
reactions. As a consequence, NOM may trigger the formation
of smaller ferrihydrite nanoparticles possessing increased
structural strain.
Mineralogical Magazine
1471
Helium rain and core erosion in gas
giant planets
BURKHARD MILITZER*
University of California, Berkeley, CA 94720, USA
(*correspondence: [email protected])
Starting with a brief overview over the search for
extrasolar planets, this talk will discuss the state of matter at
high temperature and pressure conditions that prevail in the
interiors of giant planets. We describe how data from the
Galileo mission to Jupiter has been combined with ab initio
simulations to demonstrate that there exists helium rain on this
planet [1]. Furthermore we use such simulations to predict two
new phases of water ice (figure) at megabar pressures and
characterize the associated structural and electronic transitions
[2]. Since water ice is assumed to be one of the primary
components of the cores of gas giants, we analyzed its stability
when it is exposed to metallic hydrogen. We show that the
cores of Jupiter and Saturn have been eroded [3]. We conclude
with discussing the erosion of heavier materials.
Figure 1: High pressure phases of water ice. The large and
small spheres denote the oxygen hydrogen atoms,
respectively.
The top left panel shows ice X, the highest pressure phase
seen in experiments. On the lower left, the Pbcm phase is
shown that was predicted theoretically in 1996. Recently we
used ab initio simulations to predict the existence of the two
new phases shown on the right [2]. The lower one is metallic.
[1] H. F. Wilson & B. Militzer (2010) Phys. Rev. Lett. 104,
121101. [2] B. Militzer, H. F. Wilson (2010) Phys. Rev. Lett.
105, 195701.[3] H. F. Wilson, B. Militzer, ‘Erosion of Icy
Cores in Giant Gas Planets’, http://arxiv.org/abs/1009.4722
www.minersoc.org
Goldschmidt Conference Abstracts
1472
Isotope distribution of dissolved
carbonate species in Serbian thermal
waters
N. MILJEVIC *, D. GOLOBOCANIN , J. COLIC
3
AND M. MARTINOVIC
1
2
1
Jaroslav Cerni Institute for Development of Water Resources,
Jaroslava Cernog 80, 11226 Belgrade, Serbia
(*correspondence: [email protected])
2
Vinca Institute for Nuclear Sciences, POB 522, 11001
Belgrade, Serbia
3
University of Belgrade, Faculty of Mining and Geology,
Belgrade, Serbia ([email protected])
1
In this paper we will discuss the results relative to the
major ion composition of the thermal waters, along with the
"13C composition of the dissolved inorganic carbon, and to
evaluate the interaction processes occurring between gas and
thermal reservoirs in different geodynamic environments as
well as the origin of dissolved CO2. The "13C of CO2 leaving
thermal springs ranges from -8.2 to 5.6 ‰ (vs. PDB, n=9),
while the "13C of dissolved inorganic carbon (DIC) in water
ranges from -18.4 to +1.8 ‰ (n=53) [1] (Fig. 1).
Effect of ocean acidification on
processes in the ocean
FRANK J. MILLERO
Rosenstiel School of Marine and Atmospheric Science,
University of Miami, Miami, FL USA 33149
The burning of fossil fuels has increased the pCO2 in the
atmosphere from 280 ppmv to 385 ppmv over the last 200
years. This increase is larger than has occurred over the past
800 ky. Equilibration of this CO2 with surface waters will
decrease the pH (called Ocean Acidification) from current
values of 8.1 to values as low as 7.4 over the next 200 years.
The decrease in the pH of ocean waters can affect chemical
and biological processes that occur in the oceans. Many recent
studies have shown that ocean acidification can affect the
production and dissolution of CaCO3 (s) microorganisms in
surface waters. Ocean acidification can also affect ionic
equilibria such as acid-base and the formation of metal
complexes. Many oxidation-reduction reactions of metals are
also affected by changes in the pH.
In this paper, I will examine how ocean acidification of
seawater can affect the state of metal ions. The decrease in pH
can cause a decrease in the concentration of inorganic (OH-,
CO32+ ions) and organic ligands that complex many metals in
natural waters. This will change the speciation of many metals
in seawater. Uncomplexed Cu2+ is toxic to bacteria and
phytoplankton while uncomplexed Fe2+ is more available for
the growth of phytoplankton Since organic ligands in natural
waters can form strong complexes with metals, more studies
are needed on the effect of metal organic complexes.
Figure 1: TDIC (Total Dissolved Inorganic Carbon) contents
vs. "13CDIC togather with &13CCO2gas (theoretical) for thermal
waters [2].
Water isotope compositions indicate that most waters are
meteoric in origin or resulting from mixing between meteoric
water and heavy isotope end members.
[1] Miljevic et al.(1996) J. Serb. Chem. Soc. 61, 831–840.
[2] Grassa et al. (2006) Pure Appl. Geophys. 163, 781–807.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Redox- and diffusion-controlled
fractionation of Fe stable isotopes in
silicate minerals of igneous rocks
MARC-ALBAN MILLET, JOEL BAKER,
MONICA HANDLER, CONSTANCE PAYNE
AND JESSICA DALLAS
School of Geography, Environment and Earth Sciences,
Victoria University of Wellington, New Zealand
Amongst the non-traditional stable isotopic systems
available for study in high temperature geochemistry, Fe
isotopes have received particular attention. However, the
controls of Fe stable isotope fractionation in high temperature
magmatic systems are not fully understood, mainly due to
poorly constrained isotopic fractionation factors between
silicate minerals and melts.
We present new Fe stable isotope data obtained using a
high precision double-spike technique ("56Fe ± 0.02‰, 2 sd)
for minerals from terrestrial (basalt-rhyolite, gabbro-granite,
boninite) and extraterrestrial igneous rocks (angrites, eucrites,
mesosiderites). Results show that significant mineral isotopic
fractionations exist in terrestrial samples that appear to be
controlled by Fe redox state ("56FeIRMM-14 = -1.0 to +0.85‰).
Fe2+-rich minerals like olivine display enrichments in light Fe
("56FeIRMM-14 = -0.35 to -0.25‰) compared to host melt
("56FeIRMM-14 = +0.05 to +0.22‰). Conversely, Fe3+-rich
minerals like plagioclase have heavy Fe ("56FeIRMM-14 = +0.25
to +0.42‰), and alkali feldspar exhibits markedly heavy Fe
("56FeIRMM-14 = +0.85‰). Clinopyroxene typically has a Fe
stable isotopic composition the same or only slightly lower
than host melt. In contrast to the terrestrial samples, olivine,
pyroxene and plagioclase from basaltic meteorites formed on
planetesimals that differentiated in the early Solar System
under reducing magmatic conditions do not show measurable
Fe stable isotope fractionations. This demonstrates isotopic
fractionation between Fe2+ and Fe3+ in high temperature
magmatic systems, which is then captured in terrestrial
igneous rocks when minerals incorporate various proportions
of these two Fe pools according to their mineral chemistry.
Analyses of single olivine crystals from a basaltic andesite
erupted in a subduction zone setting display an extreme
isotopic range ("56FeIRMM-14 = -0.96 to +0.19‰). Evidence for
chemical zonation in the olivine related to Fe-Mg
interdiffusion between olivine and melt suggests that
significant stable Fe isotopic fractionation in the olivines may
be due to diffusion-driven processes. This dataset will be
complemented by Mg stable isotopes of the same grains in
order to assess the relative importance of redox- and diffusioncontrolled processes on Fe stable isotopic fractionation in high
temperature magmatic systems.
Mineralogical Magazine
1473
Carbon isotope fractionation
associated with CaCO3 precipitation
induced by ureolysis
S.C. MILLO*, M. DUPRAZ, F. ADER, C. GUYOT,
R. THALER AND B. MENEZ
IPGP-Sorbone Paris Cité, Univ. Paris Diderot, UMR7154
CNRS, Paris, France (*correspondence: [email protected])
It is increasingly recognized that carbonate precipitation
by microorganisms presents some similarities with the
carbonate biomineralization of skeleton-forming organisms.
For example, in both processes crystallization often starts with
the formation of amorphous carbonate, and the polymorphism
and habit of carbonate crystals are influenced by interactions
with the cell membrane or with extracellular organic products.
However, if the occurrence of vital isotopic effects has been
extensively documented for skeleton-forming organisms, so
far the potential vital effects associated with microbial
carbonate precipitation have remained unexplored.
Paleoenvironmental reconstructions based on microbial
carbonates therefore rely on the assumption that the carbon
isotope fractionation expressed during microbial carbonate
precipitation is equal to that expressed during inorganic
precipitation at isotopic equilibrium.
We performed an experimental study of the carbon isotope
fractionation expressed during CaCO3 precipitation associated
with ureolysis induced by Sporosarcina pasteurii used as a
model organism for carbonate precipitation by heterotrophic
bacteria. The crystallization sequence initiates with the
formation of amorphous calcium phosphate followed by
vaterite and then calcite, which dominates the CaCO3 products
at the end of precipitation. The carbon isotope composition of
CaCO3 evolves following a typical Rayleigh distillation
pattern, which can be modeled assuming precipitation with no
isotopic re–equilibration between CaCO3 crystals and
dissolved inorganic carbon (DIC). According to this model,
the first stage of precipitation, possibly of vaterite, is
characterized by an increasing 13C–depletion of CaCO3
relative to DIC of up to 2‰. The second stage, probably of
calcite, proceeds very close to calcite precipitation isotope
equilibrium. These results suggest that vital isotopic effects
are probably not limited to skeleton-forming organisms but
may also occur during microbial biomineralization, where
they might be related to the initial precipitation of metastable
mineral phases.
www.minersoc.org
1474
Goldschmidt Conference Abstracts
U-Pb geochronology and Lu-Hf
isotope data from meta-carbonatites
in the southern Canadian Cordillera
LEO J. MILLONIG1*, AXEL GERDES2
1
AND LEE A. GROAT
Department of Earth and Ocean Sciences, University of
British Columbia, 6339 Stores Road, Vancouver, BC,
Canada, V6T 1Z4 (*correspondence: [email protected])
([email protected])
2
Institut fuer Geowissenschaften, Goethe University Frankfurt,
Altenhoeferallee 1, Germany
([email protected])
1
Of the 14 carbonatites in British Columbia [1] only 7 have
been dated yielding a wide range of dates interpreted as
intrusion ages, which cannot be explained within a coherent
tectonic setting. The scope of this study is to provide reliable
age data for several undated and/or previously unknown
carbonatites.
U-Pb and Th-Pb ages of zircons and accessory phases
from meta-carbonatites, obtained by LA-SF-ICP-MS
techniques, of the southern Canadian Cordillera provide
evidence for two episodes of carbonatitic magmatism during
the Cambrian at around 500 Ma and the Late Devonian to
Early Carboniferous at ~360-340 Ma. Furthermore, episodes
of regional metamorphism are recorded by Pb-loss of the
zircons and/or new zircon growth at ~170 Ma, 70-65 Ma and
~50 Ma. Lu-Hf isotope data from these zircons show a
complex pattern of homogenous to strongly varying values
between and within samples, indicating isotopic differences in
the magmatic sources or different degrees of isotopic
disturbance during metamorphism. In addition, U-Pb age
dating of the accessory phases allanite, apatite, baddeleyite,
monazite, pyrochlore, titanite and zirconolite will be
conducted in order to determine the intrusion ages and the
timing of high-grade metamorphism as well as its effect on the
different minerals.
In this study 10 carbonatite, 2 mafic and 4 syenite samples
are currently being processed and the results will provide new
constraints on the geodynamic evolution of the Canadian
Cordillera with regard to carbonatitic-alkaline magmatism.
This in turn will help to elucidate why some of the
investigated carbonatite-alkaline complexes are of economic
interest with regard to the Rare Earth Elements (REE) and Ta
and Nb.
Long period oscillations in the
Neoproterozoic carbon cycle
BENJAMIN MILLS1*, ANDREW J. WATSON1,
COLIN GOLDBLATT2, RICHARD BOYLE1
1
AND TIMOTHY M. LENTON
School of Environmental Sciences, University of East Anglia,
Norwich, NR4 7TJ, U.K
(*correspondence: [email protected])
2
Astronomy department and Virtual Planetary Laboratory,
University of Washington, Box351580, Seattle, WA
98195, USA
1
The proposed Neoproterozoic snowball Earth events imply
a super-greenhouse period following deglaciation, in which
the high CO2 concentration required to initiate glacial retreat
coupled with the decrease in planetary albedo causes greatly
elevated surface temperature [1]. In this situation, increased
reaction kinetics would drive greater silicate weathering
fluxes, which draw down CO2 until a steady state is achieved
[2].
However, the speed at which the system returns to steady
state is highly dependent on the global erosion rate. When
temperature and runoff are very high, the supply of cations to
the weathering zone becomes a limiting factor for silicate
weathering [3]. Using estimates for post-snowball CO2
concentration [1, 4] and the Phanerozoic average erosion rate
[5] yields a stabilisation time of >107 years in the COPSE
biogeochemical model [6], comparable with the timing of
Neoproterozoic glaciations.
Extended periods of high temperature and nuteirnt
abundance following a snowball glaciation may help to
explain the biological advances made over the
Neoproterozoic, as well as the geochemical features such as
long positive excursions in &13C and massive deposition of
phosphorus. Conversely, evidence that CO2 concentration
quickly returned to low levels might help constrain our views
on snowball Earth.
[1] Hoffman et al. (1998) Science 281, p. 1342–1346.
[2] Walker et al. (1981) JGR 86, p. 9776–9782. [3] West et al.
(2005) EPSL 235, p. 211–228. [4] Pierrehumbert (2005) JGR
110. [5] Wilkinson & McElroy (2007) GSA Bulletin 119, p.
140–156. [6] Bergman et al. (2004) Am.J.Sci. 304, p. 397–
437.
[1] Woolley & Kjarsgaard (2008) Carbonatite occurences of
the world, Map & Database. Geological Survey of Canada,
Open File 5796.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Experimental evidence for coarsening
of crystals and bubbles during
thermal cycling of mafic and silicic
magmas
R.D. MILLS* AND A.F. GLAZNER
Dept. of Geological Sciences, Univ. of North Carolina, Chapel
Hill, NC 27599, USA
(*correspondence: [email protected])
Porphyritic textures in igneous rocks are commonly
interpreted as evidence for low nucleation rates and/or high
growth rates, but experiments in both magma analog systems
and ice cream show that temperature oscillations can promote
crystal cannibalism and coarsening, and thus porphyritic
texture. Here we show that thermal cycling significantly
increases crystal and bubble size during experiments on a
basalt at 1-atm in a gas-mixing furnace and on a watersaturated rhyolite at 100 MPa in a cold-seal furnace.
The basalt experiments clearly show that temperature
cycling dramatically increases crystal sizes. Experiments were
performed on an alkali basalt at 1160°C, Ni-NiO buffer, for
durations of 20 to 120 hours. After thermal cycling with
amplitudes of 5 to 20°C and periods of 20 to 40 minutes, the
larger plagioclase crystals were ~20 times more massive, and
the larger olivine crystals ~5 times more massive, than in
comparable static experiments. Cycle amplitude and period
interact in complex ways with crystal structure to produce
coarsening, but all cycled experiments show increased
coarsening compared to the experiments at constant
temperature.
Initial results from experiments in a water-saturated
rhyolitic system at 100 MPa and 810°C indicate that cycling
of 10°C at a period of 40 minutes greatly increases the size of
plagioclase (mass ratio ~12) and hornblende (~4). These
results indicate that temperature cycling may offer a way to
attack the kinetic problems inherent in experimental work in
high-silica systems.
In both sets of experiments, thermal cycling caused
marked coarsening of bubbles. Although the processes by
which bubbles coarsen are probably different from those that
govern crystal coarsening, the results are very similar.
Thermal cycling greatly increases the size of bubbles and
decreases their number, suggesting that thermal cycling could
play an important role in degassing of magmas and ultimately
in determining the explosivity of eruptions.
1475
Jiaodong gold district, Northeast
China: Discrepancies with orogenic
gold mineralisation
S.E. MILLS* AND A.G. TOMKINS
School of Geosciences, Monash Uni, Melbourne, Australia
(*correspondence: [email protected])
The world-class gold deposits of the Jiaodong Peninsula
represent the most important gold-producing area in the
world’s leading gold-producing country. They are considered
by some researchers to be orogenic gold deposits; however
this study shows this classification ignores fundamental
differences in mineralisation character.
Typical orogenic gold mineralisation is associated with
compressional
or
transpressional
tectonics
in
a
collisional/accretionary setting and is commonly hosted in
metamorphosed terranes. In Jiaodong, it is well accepted that
mineralisation occured in extensional tectonics that included
lithospheric thinning and large-scale granitic emplacement [1];
fieldwork from this study also shows evidence for
mineralisation during normal faulting. Likewise, at the time of
mineralisation Jiaodong was far inboard of the active
subduction front (Paleo-Pacific Plate subducting benath the
East Asian margin), and although metamorphosed
Precambrian basement is present, mineralisation is almost
exculsively hosted in Mesozoic granitic intrusions. Also, the
Precambrian basement reached upper-amphibolite to granulite
facies metamorphism at ~2.5Ga, resulting in devolitalization
and making it unlikely that mineralisation is related to
basement metamorphism [2].
Results from this study also illustrate that deposit scale
characteristics are contrary to orogenic deposits, including
high base-metal enrichment (600, 150, 35 times background
for Cu, Pb, and Zn respectively) in the form of polymetallic
mineralisation (chalcopyrite and galena) proximal to
controlling faults in high-grade Au zones. Gold-associated
enrichments include Ag, Bi, As ± Sb, Mo, W with low Au:Ag
(0.005 to 1.66, average 0.4). Sulfur isotope analyses on pyrite
show &34S values ranging from +6‰ to +13‰ with an average
of +9‰.
These regional to deposit scale characteristics show that
although Jiaodong deposits have some similarities to orogenic
systems, major discrepancies exist. It is likely that dynamic
processes in the lithosphere and asthenosphere (i.e. mantle
lithosphere destruction, asthenospheric upwelling) were
instead the regional drivers behind mineralisation.
[1] Mao, J. et al. (2008) Ore Geology Reviews 33, 361–381.
[2] Zhao, G. et al. (2001) Precambrian Research 107, 45–73.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
1476
The fate of organic pollutants in soil –
Emerging views on the relevance of
non-extractable residues
ANJA MILTNER *, KAROLINA NOWAK ,
CRISTOBAL GIRARDI1, ANDREAS SCHÄFFER2
1
AND MATTHIAS KÄSTNER
1
1
UFZ - Centre for Environmental Research, Department of
Environmental Biotechnology, Leipzig, Germany
(*correspondence: [email protected])
2
RWTH Aachen, Department of Environmental Biology and
Chemodynamics, Aachen, Germany
1
C from soil pollutants partitions into parent compound,
metabolites, non-extractable residues (NER), CO2 and microbial biomass. This distribution must be known to assess the
fate of a compound in soil, but simulation tests in soils are
rarely performed because they are expensive and complex.
Data from aqueous systems are much more abundant, and
using them for fate assessment in soils would increase the
database enormously. The main obstacle for this is that NER
formation cannot be simulated in aqueous systems. In the past,
NER were considered to mainly consist of adsorbed and
sequestered parent compound or metabolites and thus hazardous. However, they may partly derive from bacterial biomass, resulting in harmless biogenic residues. We compared
the biodegradation of isotope labeled 2, 4-D, ibuprofen and
ciprofloxacin in aqueous systems and soil and quantified the
contribution of microbial residues to NER in soil. Both 2, 4-D
and ibuprofen were mineralized fast in aqueous systems. In
soil, mineralization was lower, and significant amounts of
NER were formed. The amount of label found in biomolecules
indicated that virtually all of the NER derived from microbial
biomass. We found no mineralization of ciprofloxacin in
aqueous systems, but a low mineralization in soil. NER
formation from ciprofloxacin was fast and independent of
microbial activity. Ciprofloxacin reduced microbial activity
more in aqueous systems than in soil, because sorption and
spatial inaccessibility reduced the toxicity in soil. In conclusion, for readily degradable compounds, mineralization is
lower in soil than in water, and a significant part of the carbon
is channeled to microbial biomass, which later is stabilized in
soil organic matter, resulting in biogenic residues. Toxic
compounds are mineralized more easily in soil than in water,
because NER formation, spatial heterogeneity, and microbial
biodiversity in soil reduce the toxicity of the compounds. NER
formation without corresponding mineralization indicates
formation of potentially hazardous NER derived from the
parent compounds or (toxic) metabolites. In contrast, NER
formed along with significant mineralization are biogenic and
thus non-hazardous.
Mineralogical Magazine
Boron isotopes by laser ablation
MC-ICPMS
J. ANDY MILTON*, FRANCES DEMUTH,
GAVIN L. FOSTER AND MARTIN R. PALMER
School of Ocean and Earth Science, National Oceanography
Centre, Southampton, Southampton, UK
(*correspondence: [email protected])
The invention of multicollector inductively coupled
plasma mass spectrometers (MC-ICPMS) has revolutionised
the way in which a number of isotope systems are measured.
Not least the light dual-isotope systems such as boron where
the large, but stable, mass fractionation of the plasma ion
source allows accurate correction using bracketing standards
of known isotope composition [1]. An additional advantage of
these instruments is the ability use a laser ablation introduction
system that allows relatively precise isotopic analysis, without
prior chemical purification, on the scale of 10-100’s of
microns (e.g. [2]). The few studies that report boron isotopes
by LA-MCICPMS [3, 4] are very encouraging, especially
given the obvious advantages offered by rapid sample
throughput and high spatial precision by LA and the
difficulties associated with boron isotope analysis by solution
MC-ICPMS (e.g. poor washout, low sensitivity, and the
difficulties associated with silicate dissolution).
Here we present our recent efforts investigating the
accuracy and precision of boron isotope analysis by LAMCICPMS of a variety of samples and reference materials
(glass, tourmaline, carbonates). Our initial results suggest
accurate and precise data, rivalling the most precise solution
analyses [1], can be generated in situ on samples amounting to
<0.5 ng of boron.
[1] Foster (2008) EPSL, 271, 254–266. [2] Foster & Vance
(2006) Nature, 444, 918–921. [3] le Roux et al. (2004) Chem.
Geol. 203, 123–138. [4] Fietzke et al. (2010) JAAS doi,
10.1039/c0ja00036a.
www.minersoc.org
Goldschmidt Conference Abstracts
Assessing the role of microorganisms
in biogeochemical processes by
protein immunodetection using
nanoSIMS
J. MILUCKA1*, L. POLERECKY1, I. LIEBERWIRTH2,
M. SCHÜLER3, T. KEIL3, T. VAGNER1, F. WIDDEL1
1
AND M.M. M. KUYPERS
Max Planck Institute for Marine Microbiology, 28359
Bremen, Germany
(*correspondence: [email protected])
2
Max Planck Institute for Polymer Research, 55128 Mainz,
Germany
3
Max Planck Institute of Biochemistry, 82152 Martinsried,
Germany
1
Anaerobic oxidation of methane (AOM) coupled to sulfate
reduction, performed by consortia of methanotrophic archaea
(ANME) and sulfate-reducing Deltaproteobacteria, plays a
crucial role in biogeochemical carbon and sulfur cycling in
marine sediments. We developed a method that allowed us to
visualize single cells in AOM consortia, identify these cells
based on the presence of key enzymes and determine their
elemental and isotopic composition.
First, thin sections of AOM aggregates were prepared and
examined by fluorescence microscopy. The discrimination
between ANME and Deltaproteobacteria was achieved by
using fluorescent antibodies targeting specific enzymes of
each of the two organisms. Next, the sample preparation and
immunolabeling protocol was successfully adapted for
nanometer-scale
secondary
ion
mass
spectrometry
(nanoSIMS). We selectively targeted the ANME with primary
antibodies against methyl-CoM reductase – the key enzyme of
AOM – and NanoGold-coupled secondary antibodies. The
obtained nanoSIMS images revealed an unusually high
phosphorus and iron content of the ANME-associated
bacteria. The transmission electron microscopy coupled to
energy-dispersive X-ray spectroscopy (TEM/EDX) showed
that these bacterial cells contained peculiar amorphous ironand phosphorus-rich particles in their cytoplasm.
Based on these results we speculate that AOM might also
play a – yet unrecognized – role in iron and/or phosphorus
cycling in marine sediments. This demonstrates that
imunodetection of key enzymes in combination with
nanoSIMS can be used to assess the involvement of functional
groups of organisms in biogeochemical processes.
Mineralogical Magazine
1477
Reaction of silicate with released CO2
by inorganic precipitations of marine
carbonate in sandstone: Evidence
from 87Sr/86Sr, !18O and !13C isotopes
in calcareous sandstone
MASAYO MINAMI1, TSUYOSHI TANAKA2*,
MAKOTO TAKEUCHI3 AND SAEKO MITO4
Center for Chronological Res., Nagoya Univ., Nagoya 4648602 Japan ([email protected])
2
Center for Chronological Res., Nagoya Univ., Nagoya 4648602 Japan and RITE, Kyoto 619-0292 Japan
(*correspondence: [email protected])
3
Earth and Environmental Sci., Nagoya Univ., Nagoya 4648602 Japan ([email protected])
4
Res. Inst. of Innovative Technology for the Earth, Kizugawa,
Kyoto 619-0292 Japan ([email protected])
1
87
Sr/86Sr, #18O and #13C isotopes of carbonate in calcareous
sandstone show intermediate values between marine carbonate
and silicate phase of the sandstone.
Triassic Hiraiso Formation of the South Kitakami Terrane
in Japan contains calcareous sandstone. The carbonate
distributed homogeneously in lithic fragments and partly
replaced plagioclase of the sandstone. It is considered that the
early Triassic period was a dried climate and the Hiraiso
Formation was deposited at near shore marine. The carbonate
phase and silicate phase were separately examined. 87Sr/86Sr
and #18O isotopes of the carbonate phase are lower than the
values of limestone at that Triassic period. The values show
the intermediate between silicate minerals and marine
carbonate, while #13C shows the value of marine carbonate.
The 87Sr/86Sr and #18O isotopes indicate that these are the
mixed ones of marine Sr and oxygen with those in silicate
phase. Very few carbon is contained in the silicate phase and
the #13C value shows always that of marine. It shows
simultaneous formations of the 1st: Carbonate precipitation
from seawater in the sandstone with 2nd: Precipitation of
carbonate by the quick reaction of silicates and the nascent
carbon dioxide released at that time.
www.minersoc.org
1478
Goldschmidt Conference Abstracts
Anthropogenic aerosols and the
weakening of the South Asian
summer monsoon
YI MING1, MASSIMO BOLLASINA2
3
AND V. RAMASWAMY
Geophysical Fluid Dynamics Laboratory/NOAA, 201
Forrestal Road, Princeton, NJ 08540 ([email protected])
2
Program in Atmospheric and Oceanic Sciences, Princeton
University, Princeton, NJ 08540
([email protected])
3
Geophysical Fluid Dynamics Laboratory/NOAA, 201
Forrestal Road, Princeton, NJ 08540
([email protected])
1
an integral component of the Earth’s hydrological cycle,
the South Asian summer monsoon is critical for the well-being
of over one-fifth of the world’s population. Observations show
that South Asia underwent a widespread drying during the
second half of the twentieth century, but it is still largely
unclear whether this prolonged shift was due to natural
variations or human activities. Here we use a series of
perturbation experiments with a state-of-the-art climate model,
which realistically simulates the observed historical trend
when driven with all known climate forcings, to investigate
the South Asian monsoon response to natural and
anthropogenic factors, with particular focus on aerosols and
greenhouse gases. We find that the observed precipitation
decrease is very likely to be of anthropogenic origin, and can
be attributed almost entirely to aerosols. The drying is a robust
outcome of a slowdown of the tropical meridional overturning
circulation, which is fundamentally driven by the need to
counteract the aerosol-induced energy imbalance between the
northern and southern hemispheres. In contrast, greenhouse
gases give rise primarily to a weakening of the equatorial
zonal overturning circulation. These results provide
compelling evidence of the prominent role of aerosols in
shaping regional climate change over South Asia.
Volatiles (H2O, CO2, S, Cl, F) in
primary magmas of Kliuchevskoy
volcano (Kamchatka)
N. MIRONOV1* AND M. PORTNYAGIN1,2
V.I. Vernadsky Institute of Geochemistry and Analytical
Chemistry (GEOKHI RAS), Kosygin str. 19, 119991
Moscow, Russian
(*correspondence: [email protected])
2
Leibniz Institute of Marine Sciences (IFM-GEOMAR),
Wischhofstr. 1-3, 24148 Kiel, Germany
1
We carried out a melt and fluid inclusion study to estimate
the amount of volatiles (H2O, CO2, S, Cl, F) in primary
magmas of Kliuchevskoy volcano in Kamchatka. Volatiles in
melt inclusions were analyzed by EMP (S, Cl), SIMS (H2O, F)
and FTIR (CO2, H2O). Fluid inclusions were studied
criometrically. More than 400 melt and fluid inclusions in
olivine (Fo92-67) were studied. We found that diffusive H2O
loss from inclusions, redistribution of CO2 between melt and
fluid and sulfide immiscibility inside inclusions preclude
straightforward interpretation of volatile concentration in
glasses of primitive MIs (Ol-host Fo>85) as representative for
primary melts. Careful selection of the least modified after
entrapment melt inclusions allowed us to define the most
plausible range of volatile concentrations in primitive
Klyuchevskoy magmas (minimum-maximum, average, wt.
%): H2O=2.8-3.6, 3.2; S=0.13-0.23, 0.16; Cl=0.02-0.13, 0.08;
F=0.022-0.051, 0.032. A minimum CO2 content in primitive
melts is estimated from density of CO2 fluid inclusions in
primitive olivines to be 3500 ppm. Inclusions in more evolved
olivines (Fo<80), which were trapped shortly before eruption,
reflect variable extent of magma degassing and were nearly
undisturbed by the later processes of melt modification after
entrapment.
The concentration of volatiles in Kliuchevskoy melts are
similar to those estimated in other, much less productive
Kamchatkan volcanoes [3]. Given the large productivity of
this volcano (on average 60 Mt /year), the flux of volatiles
from Kliuchevskoy volcano is however very high during the
Holocene (e.g. H2O flux amounts at 3.27 Mt/year). The high
volatile flux may indicate a large part of subducting plate
delivered fluids focused to the source of Kliuchevskoy and/or
perhaps additional contribution of volatiles from serpentinites
in the subducted plate.
[1] Minerals, inclusions & volcanic processes (2008) Reviews
in mineralogy & geochemistry, 69. [2] Mironov, Portnyagin
(2011) Russian Geology & Geophysics, in press.
[3] Portnyagin et al. (2007) Earth & Planetary Science Letters
255, 53–69.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Chronology of early solar system
inferred from precise Al-Mg isotope
systematics of Vigarano CAIs
R.K. MISHRA AND M. CHAUSSIDON
Centre de Recherches Petrographiques et Géochimiques,
CRPG - CNRS, UPR 2300, 15 rue Notre Dame des
Pauvres, BP 20, 54501Vandoeuvre les Nancy, France
([email protected], [email protected])
Calcium, Aluminium-rich Inclusions (CAIs) are the oldest
solar system solids that have been absolutely dated to have an
age of ~4.57 Ga [1-2]. High precision in situ Al-Mg isotope
systematics studies of CAIs, and other early formed solar
system objects, using secondary ion mass spectrometer
(SIMS) provides an opportunity to obtain very precisely time
of last melting event (from 26Al/27Al ratio) and Mg isotope
composition at this time (from &26Mg0) [3-6]. This allows
better understanding of high temperature events in the solar
accretion disk by constraining their durations with greater
precision (~105 years), the components involved (gas or
solids) and the history of these components. Eight CAIs of
different types from one of the least altered meteorite
Vigarano (CVreduced 3.1-3.4) were analysed for Al-Mg isotopic
composition in order to answer several first order questions:
(i) did condensation/melting of CAI precursors happen only
during a unique single event in the accretion disk, (ii) how
many high temperature events did CAI undergo, (iii) whether
some of these events were related with chondrule formation?
In addition, it provides arguments for quantifying the level of
homogeneity of Al, and Mg isotopes in the inner solar system
[3, 7]. Results obtained so far suggest melting of CAIs at
different periods of time from precursors extracted earlier, in a
short time interval, from the solar gas. No indication of 26Al
heterogeneity has been found.
[1] Bouvier & Wadhwa (2010) Nature geo. 3, 637–641.
[2] Amelin et al. (2010) EPSL 300, 343–350. [3] Villeneuve et
al. (2009) Science 325, 985–8. [4] Kita et al. (2010) LPSC 41
2154. [5] Davis et al. (2010) LPSC 41 2496. [6] MacPherson
et al. (2010) ApJ 711, L117-121. [7] Jacobsen et al. (2008)
EPSL 272, 353–364.
1479
Formation of the nitrogen
B-aggregates in type Ib diamond
Y. MITA1*, Y. NISIDA1 AND M. OKADA2
Graduate School of Engineering Science, Osaka University,
Toyonaka, Osaka 560-8531, Japan
(*correspondence: [email protected])
2
Research Reactor Institute, Kyoto University, Sennan, Osaka
590-0451, Japan
1
Most of natural diamonds contain nitrogen atoms more or
less and they form many types of aggregates by annealing.
When the diamonds contain nitrogen atoms in single
substitutional form, in substitutional nitrogen pairs (named Acenters) or in B-aggregate form, they called type Ib, type IaA
or type IaB, respectively. As many natural diamonds are their
mixed types and contain impurity atoms in reality, all types of
diamonds must be obtained artificially for investigation.
However to form the nitrogen B-aggregates consist of four
substitutional nitrogen atoms surrounding a vacancy from
isolated nitrogen atoms of type Ib diamond the samples must
be annealed for an extraordinary long time under high
temperature and high pressure conditions. Therefore it was
thought till recently that to form the B-aggregates artificially is
preposterously difficult and a diamond which contains the Baggregates is natural. Collins [1] observed formation of the Acenters in the electron irradiated and annealed type Ib diamond
and thought that the aggregation of nitrogen is enhanced by
vacancies introduced due to the electron irradiation. However
this treatment was not enough powerful for generating big
nitrogen aggregates like the B-aggregate.
We studied the neutron irradiation effects on the nitrogen
aggregation in type Ib diamonds. The nitrogen concenteration
of samples were ranged from 50 to 340 ppm and the neutron
irradiation was carried out with doses of 1.1J1016 n/cm2 to
2.8J1018 n/cm2. The samples were annealed at various
temperatures between 1000 to 1700 centigrade degrees for
several annealing times under a pressure of 6 GPa. It was
observed that the aggregation due to the high temperature and
high pressure annealing is highly accelarated by vacancies
introduced through the neutron irradiation and a large amount
of B-aggregate was generated from single nitrogen. The best
record of generation time of B-aggregates at present is shorter
than 30 minutes.
[1] Collins (1980) J. Phys. C, Solid St. Phys. 13 2641–2650.
Mineralogical Magazine
www.minersoc.org
1480
Goldschmidt Conference Abstracts
River red gum biogeochemical
expression of buried Broken Hill type
mineralisation
C. MITCHELL1* AND S.M. HILL2
The University of Adelaide, Adelaide, 5005, Australia
(*correspondence: [email protected])
2
The University of Adelaide, Adelaide, 5005, Australia
([email protected])
1
River red gums (Eucalyptus camaldulensis) are a tree
native to Australia but now widely grown in warm and semiarid parts of the world. In Australia, they are one of the most
widely distributed tree species, especially in riparian zones of
arid regions. Their distribution closely corresponds to areas
where sediments and and alluvial aquifers are well developed.
As such, they tend to colonise settings where the underlying
bedrock geochemistry is poorly defined. These long-lived and
deep-rooted trees therefore have potential to provide important
biogeochemical expressions of the geochemistry of buried
bedrock. This study provides an overview of multi-element
(ICP-MS and XRF) analysis of leaf samples from about 500
river red gum trees from the Broken Hill region in semi-arid
central Australia. Particular attention is given to the
biogeochemical expression of sites of known Broken Hill type
(Ag-Pb-Zn) mineralisation. It shows that biogeochemistry can
provide an effective recognition of buried mineralisation, even
when the overlying sediments do not contain a geochemical
expression that distinctly highlights mineralisation. It also
provides an indication of some of the highly elevated metal
and trace element contents that can be hosted in native
vegetation near the natural occurrences of ore bodies.
Samples from trees overlying mineralisation near the
Pinnacles Mine and along the Broken Hill Line of Lode show
highly elevated contents of Ag (max. 1.36 ppm), Pb (max. 411
ppm) and Zn (max. 338 ppm), where regional 'background'
values are typically low or approaching analytical detection
limits (e.g. Ag 0.01 ppm; Pb 1 ppm; and, Zn 17 ppm). Some
samples from near mineralisation also contain elevated Cd,
Au, In and Tl contents, however, values are variable, and these
elements are best considered within the context of the major
ore forming elements (e.g. In/Zn). The spatial extent of the
elevated biogeochemical response depends on the size and
grade of mineralisation but also the characteristics of the
physical and chemical dispersion that vary in different parts of
riparian zones.
Mineralogical Magazine
Selenium adsorption and associated
selenium isotope fractionation
K. MITCHELL1*, R.-M. COUTURE1, T.M. JOHNSON2,
P.R.D. MASON3 AND P. VAN CAPPELLEN1
Georgia Institute of Technology, Atlanta, USA
(*correspondence: [email protected])
2
University of Illinois at Urbana-Champaign, Urbana, IL, USA
3
Utrecht University, Utrecht, The Netherlands
1
Riverine input is a source of selenium to the coastal
oceans: between 5 and 12% of Se input consists of particulate
selenium. Depending on the site, particulate organic Se is
estimated to account for 40 to 100% of the particulate Se pool,
suggesting that up to 60% of particulate selenium is in another
form, possibly as selenium oxyanions adsorbed onto either
organic matter or iron (Fe) oxides
Among the Fe oxides, goethite has been put forth as the
dominant authigenic Fe(III) phase in freshwater and marine
sediments. Hematite is found in association with goethite,
though generally it is not as widespread. Ferryhydrite, while
short lived, is a precursor to the latter phases. Thus, these
ubiquitous phases are important carrier of adsorbed Se species
to oceans.
Nevertheless, sorption behavior of selenate and selenite as
well as the isotope fractionations associated with these
reactions has not been systematically investigated. Here, we
measured total Se concentrations as a function of time during
the equilibration of selenate and selenite with suspensions of
2-line ferryhydrite, hematite, goethite (Table 1).
2-line ferryhydrite
Hematite
Goethite
Selenite 50
0.5
275
Selenate ~0
~0
1
Table 1: Calculated partition coefficient (Kd; L g-1) for Se
sorption onto selected Fe(III) oxyhydroxide minerals.
We show that selenate does sorb onto goethite (Table 1),
contrary to expectation, albeit to a much lower extent than
selenite. We conclude by discussing the isotope shifts
associated with these sorption reactions and the potential use
of Se isotopes to fingerprint the sorption mechanism of Se
removal by Fe oxides in the aquatic environment.
www.minersoc.org
Goldschmidt Conference Abstracts
Adsorption and sorption of Zn2+ on
the surface of aluminum hydroxide
The composition of Earth’s oldest
iron formations: The Nuvvuagittuq
Supracrustal Belt (Québec, Canada)
A. MIYAZAKI1*, M. NUMATA1, M. ETOU2,
K. YONEZU3, I. BALINT4 AND T. YOKOYAMA2
Japan Women’s University, Tokyo 112-8681, Japan
(*correspondence: [email protected])
2
Faculty of Science, Kyusyu University, Fukuoka 810-8560,
Japan
3
Faculty of Engineering, Kyusyu University, Fukuoka 8190395, Japan
4
Institute of Physical Chemistry, 77208 Bucharest, Romania
A.M. MLOSZEWSKA*, E. PECOITS1, N.L CATES2,
S.J. MOJZSIS2, J. O'NEIL3 AND K.O. KONHAUSER1
1
Adsorption/sorption of heavy metal ions on clay
minerals
Clay minerals are expected as one of the most effective
adsorbent/sorbent for heavy metal ions in soil. Miyazaki et al.
[1] reported that solid-liquid interfacial reaction of Zn2+ ions
on alumina can be divided into three processes: adsorption due
to formation of inner-spehre complex, desorption of Zn2+
accompanied with dissolution of Al3+ and then co-precipitation
of Zn2+ with Al (OH)3. Shlegel and Manceau [2] reported that
after adsorption of Zn2+ onto montmorillonite, which was
exchanged with Al3+ or Keggin Al13, the Zn2+ located in vacant
octahedra of gibbsite-like layers. These reactions for Zn2+ may
correspond to transfer from adsorption to sorption. In order to
access and control the mobility of heavy metals in soil
systems, it is essential to understand the relationship between
their sorption and adsorption onto clay minerals. One of the
crucial problems is the role of Al3+ in the process of
adsorption/sorption. In this study, Zn2+ was adsorbed onto Al
(OH)3 and change in the chemical state of Al3+ in Al (OH)3
after the adorption was analyzed using 27Al MAS NMR.
Results and discussion
Al (OH)3 was prepared by hydrolisis of Al3+ in KAl
(SO4)2K12H2O solution. In the 27Al MAS NMR spectra for Al
(OH)3, a peak was observed around 5 ppm. In case of Al
(OH)3 after adsorption of Zn2+, the NMR peaks were observed
around 15 and 60 ppm depending on the experimental
condition such as pH, concentration etc. These peaks may be
AlO6 octahedral species adsorbing Zn2+ and AlO4 tetrahedral
species, respectively. Interestingly, the peak at 60 ppm was
also found in the co-precipitates of Zn2+ with Al (OH)3. From
these results, it can be assumed that adsorption of Zn2+ onto Al
(OH)3 induces Al3+ dissolution and the Al3+ precipitates on the
solid forming Keggin-like structure which correspond to the
sorption.
[1] Miyazaki et al, (2003) Geochim. Cosmoschim. Acta 67,
3833–3844. [2] Shlegel & Manceau (2007) Environ. Sci.
Technol. 41, 1942–1948.
Mineralogical Magazine
1481
Earth and Atmopsheric Sciences, University of Alberta,
Edmonton, Alberta, T6E 1Y1
(*correspondence: [email protected])
2
Geological Sciences, University of Colorado at Boulder,
90309-0399, USA
3
Terrestrial Magnetism, Carnegie Institution of Washington,
Washington DC, 20015-1305, USA
1
The composition of iron formations in the >3.8 Ga year
old [1, 2] Nuvvuagittuq Supracrustal Belt in northern Québec
provide a proxy for seawater composition of the Eoarchean,
and perhaps Hadean oceans, as well as constraints on the types
of nutrients available to Earth’s earliest life forms. Having
precipitated directly out of seawater, it is thought that the
primary iron minerals that comprised the initial BIF sediments
(e.g. ferric oxyhydroxides) retained the chemical signature of
this seawater in the process. Integrated petrologic and
geochemical relationships mapped between mineral phases in
thin section and whole-rock chemistry provides a framework
for interpreting bulk and micro-scale variations in these
chemical sedimentary precipitates. Results show that there are
two distinct chemical sedimentary units in the Nuvvuagittuq
belt: i) a BIF unit, consisting of alternating micro-bands of
magnetite, Fe-Mg-Ca-silicates and quartz, and ii) a more
silicate-rich (Fe-poor) banded silicate-formation (BSF) unit of
alternating micro-bands of quartz and Fe-Ca-silicates.
Precursor BIF and BSF deposits were layered amorphous
silica and ferric oxyhydroxides, fine-grained carbonate oozes
and/or Ca-Mg-Fe rich silicate gels deposited in a marine
setting. Low Al2O3, TiO2 and HFSE concentrations show that
they are relatively detritus-free, with distinctively seawaterlike REE+Y profiles and consistently positive Eu anomalies.
These features suggest that the rocks preserved their seawaterlike compositions despite metamorphic overprinting. The most
significant trace elements in the sediments are Ni and Zn.
Experimentally-derived partitioning coefficients show that
Earth's earliest oceans had relatively high dissolved Ni
concentrations (up to ~300 ppm) while those for Zn were
relative low (up to ~20 ppm) compared to modern seawater.
Compositional resemblances between the Nuvvuagittuq
sediments and those documented in the ca. 3.8 Ga Isua
supracrustals (west Greenland) provide a plausible case that
global ocean processes had reached steady-state by the
Eoarchean.
[1] Cates & Mojzsis (2007) EPSL. 255, 9–21. [2] O'Neil et al.
(2008) Science 132, 1828–1831.
www.minersoc.org
1482
Goldschmidt Conference Abstracts
Petrogenesis and tectonic significance
of Shuangjianshan highly evolved
I-type granite, Beishan orogen,
NW China
1
YALONG MO1.3, XINBIAO LÜ1.2*, ZHUJIANG1, DENGJIE1,
XIAOFENG CAO1 AND YUCAI DAI4
Faculty of Earth Resources, China University of Geosciences,
Wuhan 430074, China
(*correspondence: [email protected],
[email protected])
2
State Key Laboratory of Geological Processes and Mineral
Resources, China University of Geosciences, Wuhan
430074, China
3
Yunnan provincial tourism school, Kunming 650221, China
4
No. 6 Geological Party, Xinjiang Bureau of Geology and
Mineral Exploration, Hami 839000, China
We have studied the petrology, major and trace element
geochemistry, isotope geochemistry of the Shuangjianshan
intrusion and discussed its petrogenesis and tectonic
significance. The Shuangjianshan intrusion is located in south
of Hongshishan ophiolitic mélange in Beishan orogeny belt,
Gansu, north of Tarim. It is a monzogranite. The content of
SiO2 is 73.04-74.39 %, A/CNK ranges from 0.996 to 1.065,
total alkalis ranges from 8.29 to 8.44 % with Na2O over 3%,
calculated corundum is less than 1 % and DI ranges from
91.29 to 93.26. Thus, it is a highly evolved I-type granite with
total REE (146.79-157.5 ppm), (La/Yb)N (8.08-8.80) and &Eu
(0.64-0.73). It is enriched in Rb, Ba, Th, U and depleted in Ta,
Nb, Sr, Ti. Its geochemistry characters show the affinity of
island arc magmatic rock. LA-ICP-MS zircon U-Pb dating
gave the intrusive age of 322.3±1.7Ma (weighted 206Pb/238U
age). Its has high 0Nd (t) (+1.9 to +2.7), low (87Sr/86Sr)i
(0.70312!0.70343) and the samples from the intrusion plots
in the orogeny evolution trend on the 206Pb/204Pb vs. 207Pb/204Pb
diagram. It falls in the area of syn-collisional granite area on
R1-R2 diagram, however in the volcanic arc granite area on
the Y vs. Y+Nb and Y vs. Nb diagrams. The characteristics
described above indicate that the Shuangjianshan intrusion is a
highly evolved I-type granite originating from the mantle
wedge. Trace elements exibit the characteristics of subduction
zone. The granite also contaminated by crust and underwent
highly fractional crystallization. Combining with the 334 Ma
adakite, we believe that the intrusion is a later product of the
subducted North Tianshan ocean crust, which closed before
322 Ma and then came to the syn-collisional stage.
Quaternary soil and climate change
inferred from TL Dating of
Quaternary terraces in Taleghan
basin, Iran
A. MOEINI1 AND E. ALIZADE PAEEN AFRAKATY2
Department of Agriculture and Natural Resources, Science &
Research Branch, Islamic Azad University (IAU), Iran
([email protected])
2
Faculty of Environment, University of Tehran, Iran.
1
Introduction and methods
We report the first thermoluminescence ages for the
quaternary sediments of the Taleghan Drainage Basin, Tehran,
Iran.
Results
Teracces
Terrace Name
Q4
Toria War
4650+ 520
Q3
Wurm
9100 ± 800
Q2
Wurm
15600 ± 2000
Q1
Riss
54900± 8700
Table1. Result of TL dating [1, 2]
The carbonates appeared in the field as nodules in the
wurm terrace and laminar or conglomeratic massive cemented
accumulation (Petrocalcic horizons) in the Riss terrace and the
Toria war (youngest terraces), rejuvenates by flooding, and
has not secondary carbonate within the profile.
Discussion
Based upon the above observations, we theorize that, at
the ~100 ky ago climate was cold and arid, at the ~15 ky ago
climate was tardi glacial, at the ~9 ky ago climate was pluvial
and temperate with arid transitions and at the ~4 ky ago
climate was flooding [3].
[1] Aitken, M.J. (1998) Oxford University Press, Oxford.
[2] Shannon, M. (2000) (USGS) October 13, 2000.
[3] Thomas, M.F. (2004) Catena 55 (2),107–124.
This work is founded by 305 Project of State Science and
Technology Support Program (Grant No. 2007BAB25B04).
Mineralogical Magazine
Age (y)
www.minersoc.org
Goldschmidt Conference Abstracts
Cu, Zn and Fe isotope systematics of
low-T hydrothermal Fe-Si deposits
K. MOELLER1*, R. SCHOENBERG2, I.H. THORSETH1
1
AND R.B. PEDERSEN
Centre for Geobiology and Department of Earth Science,
University of Bergen, Allegaten 41, 5007 Bergen, Norway
(*correspondence: [email protected])
2
Institute for Geoscience, University of Tuebingen,
Wilhelmstrasse 56, 72076 Tuebingen, Germany
1
The formation of Si-rich ferric oxyhydroxide deposits is
observed distal to the white smoker-type Jan Mayen
hydrothermal vent fields at the Mohns Ridge, North Atlantic,
in an area of diffuse low-temperature venting. Individual
stratified laminated layers within these deposits are largely
composed of branching, twisted filaments resembling
encrusted stalks of Fe-oxidising bacteria, indicating
biologically influenced precipitation of ferric iron.
In this study, we used stable isotope systematics of
transition metals from different layers of the Fe-Si deposits in
order to trace the evolution of hydrothermal fluids within the
oceanic crust, from which these deposits ultimately formed.
Isotope measurements show fractionation of the redoxsensitive elements Fe and Cu, whereas Zn with its singular
oxidation state behaves more conservatively. Isotopically light
Fe (&56Fe = -2.09 to -0.66 ‰) points to abiogenic partial,
subsurface Fe oxidation [1] and/or dissimilatory iron reduction
in combination with re-oxidation by Fe-oxidising bacteria.
The reactive surface of the ferric oxyhydroxides of the Fe-Si
deposits may absorb Cu and Zn from the venting fluid, thereby
preferentially incorporating the heavy isotopes of these
elements [2]. However, measured Zn isotope data do not show
a significant enrichment relative to hydrothermal fluids [3]
and Cu is isotopically lighter than primary hydrothermal Cu
sulphides [4]. We hypothesize that precipitation and/or
adsorption processes below the seafloor lead to the depletion
of heavy isotopes in the evolved hydrothermal fluids from
which the Fe-Si deposits formed.
[1] Rouxel et al. (2003) Chem. Geol. 202, 155–182.
[2] Balistrieri et al. (2009) GCA 72, 311–328. [3] John et al.
(2008) EPSL 269, 17–28. [4] Rouxel et al. (2004) Econ. Geol.
99, 585–600.
Mineralogical Magazine
1483
Geochemistry of Cheshmeh Sefid
manganese deposit, Sabzevar,
Khorasan province, Iran
S.J. MOGHADDASI* AND M. GANBARI
Payame Noor University, Department of Geology, 193954697, Tehran, Iran
(*correspondence: [email protected])
Cheshmeh Sefid manganese deposit is located in 60 km
south of Sabzevar, a major city in Khorasan province,
northeast of Iran. The study area is situated in central Iran
structural zone. Manganese mineralization is occurred in a
volcano-sedimentary succession consisted of grey limestone,
submarine volcanic, Neogene sediments and flysch-like
deposits. Manganese mineralization is mainly hosted by green
colored rhyolitic tuffs of Eocene age. Manganese rich
stratiform bodies are enclosed in jasper and overlain by grey
colored dacite and rhyodacite. They are often syngenetic,
based upon the stratigraphic persistence of the manganese
horizon and the observed interstratification of manganese ore
and hosting volcanics. Manganese deposits occur as lenses and
stratiform bodies of different sizes. Upper and lower contacts
of the ore bodies are characteristically sharp. Ore
mineralography and XRD examinations were indicated that
pyrolusite, psilomelane and cryptomelane were major
manganese ore minerals in the studied deposit.
Geochemically,
iron
and
manganese
were
characteristically fractionated, producing low Fe/Mn ratios.
Si-Mn-Fe and Al-Si discrimination diagrams were also used to
recognize between hydrothermal and hydrogenous manganese
deposits. The collected geochemical data from the study area
plot in the characteristic field of hydrothermal deposits. The
manganese ores were indicated relatively low concentrations
of Ni, Co, and Cu compared with those concentrations in
hydrogenous manganese deposits. Diagnostic plot to Mn-Fe10 (Ni+Co+Cu) discrimination diagram was indicated a
characteristic depletion in Ni, Co, and Cu, suggesting a
hydrothermal origin for the studied manganese deposit.
Geochemical composition of manganese deposits of the
studied area and their host rocks indicates that manganese
oxides of the study area are the result of rapid deposition from
Mn-rich fluids. These fluids have a hydrothermal exhalative
nature and were probably associated with volcanic activities in
Eocene period.
www.minersoc.org
1484
Goldschmidt Conference Abstracts
Removal of seawater 234U
incorporated in Holocene basaltic
sediments from the Reykjanes ridge
K.J. MOHAMED1,2*, L.F. ROBINSON2,3
2,4
AND J.F. MCMANUS
University of Vigo, Vigo, Spain
(*correspondence: [email protected])
2
Woods Hole Oceanographic Instit., Woods Hole, MA, USA
3
University of Bristol, Bristol, UK
4
Columbia University, Lamont-Doherty Earth Observatory,
Palisades, NY, USA
1
The ratio (234U/238U) of detrital sediments is a potential
tool for direct determinations of sediment transport time and
provenance. Changes in grain size, shape and mineralogy after
deposition can obscure the (234U/238U) variation with time,
providing erroneous estimates of transport time. Addition of
Uranium from external sources can also change this ratio,
even to values higher than secular equilibrium.
Icelandic sediments recovered from the eastern flank of
the Reykjanes ridge, in the Björn drift, showed (234U/238U)
values higher than 1. Basalts, the main rock in the area, are
known to incorporate Uranium from seawater with a
(234U/238U) of 1.14, which may explain the anomalously high
(234U/238U) measured in our samples. To identify the source of
this 234U addition, we performed a leaching of Holocene and
deglacial sediments from the same site with increasing
concentrations of HCl.
Older sediments with initially low (234U/238U) showed little
variation with increasing acid concentration. On the contrary,
younger samples with high (234U/238U) show steep decreases at
concentrations lower than ~2.5 N HCl, and little changes from
3 to 9 N.
Leachates exhibit higher (234U/238U) than residues in all
cases. In low (234U/238U) samples, leachates decrease initially
and reverse the trend at HCL concentrations higher than 2.5 N
HCl reaching values close to secular equilibrium. Leachates
from samples with high (234U/238U) show similar behavior as
the residues.
The incorporation of seawater uranium in Holocene
samples suggests that these sediments have a higher
contribution from Icelandic basalts. This 234U contamination
from seawater can be removed by leaching with 2.5 N HCl,
which increases the reliability of transport time estimates
based on the (234U/238U) ratio. Higher HCl concentrations may
dissolve the sediment grains, which releases detrital 234U and
would explain the reversed trend observed in the leachates
above 2.5 N HCl.
Mineralogical Magazine
Helium in Michigan Basin sediments:
A tracer for pore fluid migration and
age
R.K. MOHAPATRA1*, I.D. CLARK1, R.E. JACKSON2,
K. RAVEN2 AND M. JENSEN3
Dept. of Earth Sciences, University of Ottawa, Ottawa, ON
Canada, K1N 6N5
(*correspondence: [email protected])
2
Geofirma Engineering, Ottawa
3
Nuclear Waste Management Organization, Toronto
1
As a central component of hydrogeological investigations
at a proposed site for low and intermediate level nuclear waste
disposal, we have measured He in Ordovician strata from the
Deep Geological Repository site in the Michigan Basin near
Tiverton, Southern Ontario. Samples were micro-cored (6mm
dia., 20mm length) from full 76 mm core samples of shales
and argillaceous limestones shortly after recovery from depths
between 450 and 850 m, for measurement of He on a MAP
215-50 mass spectrometer (MAPL). Supplemented by stable
isotope measurements and major and trace element
geochemistry, the labile helium fraction is used to estimate
pore fluid age and source location. The xRa profile shows a
consistent value near 0.0200 ± 0.0015 in the very low
permeability Upper Ordovician shales, with a shift to 0.0360
±0.0020 in the underlying Middle Ordovician limestones. In
situ production rates for 3He from 6Li fission and 4He from U
and Th decay in the shales provide a calculated xRa that,
within the margin of uncertainty, is the same as the measured
ratio, suggesting an autochthonous source for He in that
section. Pore fluid age, based on the calculated 4He production
rate and measured He concentrations in the shales, indicates
accumulation over ~ 200 Ma. In the very low permeability
limestones the calculated in situ xRa of 0.001 to 0.004
suggests an allochthonous He source. The xRa value of 0.036
measured in the limestones was indistinguishable from that
measured in the thin basal Cambrian sandstone aquifer
groundwater collected during the study. This value may be
explained by a mixture of a mantle 3He-enriched end member
derived from the rifted base of the Michigan Basin and He
from the Canadian Shield.
www.minersoc.org
Goldschmidt Conference Abstracts
Isotopic data from the Pomarinho
enclave swarm (SW Iberian Chain)
The ca. 4.2-3.7 Ga history of the
Acasta Gneiss Complex (Northwest
Territories, Canada)
P. MOITA1, J.F. SANTOS2 AND P. SILVA3
S. MOJZSIS1*, N. CATES1, A. MAIER1, M. HOPKINS1,
D. TRAIL2, M. GUITREAU3, O. ABRAMOV1,4
5
AND W. BLEEKER
HERCULES, CGE, Univ. Évora ([email protected])
GeoBiotec, Univ. de Aveiro ([email protected])
3
IDL, ISEL, Lisboa ([email protected])
1
2
Mafic microgranular enclaves are a common feature of
calc-alkaline granitoids (e.g. tonalites and granodiorites) in
active continental margins and collisional orogens. They
correspond to dark-coloured globules that, although
widespread throughout the host rock, usually constitute only a
small proportion of the whole volume of the intrusion. When
the enclaves occur strongly concentrated in a restricted area,
they form an enclave swarm (e.g. [3]). At Pomarinho, the
Granialpa quarry is a privileged exposure of a cluster of dark
igneous enclaves that has been targeted for geochemical and
geophysical studies (GeoRadar and AMS).
The Pomarinho swarm is located in the SW edge of Évora
granitoid (Carvalhosa, 1983), in the Portuguese sector of the
Ossa-Morena Zone (Iberian Variscides). The enclaves have
tonalitic and granodioritic compositions, whereas the host
correspond to a very homogeneous light-coloured
granodiorite. Preliminary geochemical information, based on
major and trace elements [2], suggests that the enclaves and
the host rock are probably derived from co-genetic magmas.
Rb-Sr isotope data now obtained in four enclaves and
three host-rock samples yield an isochron corresponding to
335±14Ma (MSWD=0.96), which fits into the spectrum of
ages of the Variscan granitoids in the region. Additionally, the
homogeneity of both 87Sr/86Sr335 (0.704758 to 0.705133) and
0Nd335 (-0.10 to 1.13) values corroborates the hypothesis of
derivation of the enclaves and the host granodiorite from a
common primitive melt through magmatic differentiation.
Low 87Sr/86Sr335 and high 0Nd335 values suggest that ultimately
the parental melt is related to a mantle source, with no or only
small contribution of metasedimentary crustal materials.
Funding:
Petrochron
GIX/112561/2009)
project
(PTDC/CTE-
[1] Carvalhosa, A. 1983. Esquema geológico do Maciço de
Évora. Comun. Serv. Geol. Portugal 69 (2), 201–208.
[2] Moita, P. Santos, J.F. Silva, P. & Pardal, E. (2011)
Geochemical signature of the Pomarinho enclave swarm
(Ossa-Morena Zone, Portugal) Abstract, Hutton Symposium.
[3] Tobish, O.T. McNulty, B.A. & Vernon, R.H. (1997)
Microgranitoid enclave swarms in granitic plutons, central
Sierra Nevada, California. Lithos 40, 321–339.
Mineralogical Magazine
1485
CU, Geol. Sci., Boulder, CO 80309-0399 USA
(*correspondence: [email protected])
2
RPI, Earth & Environ. Sci., Troy, NY 12180 USA
3
ENS, LGLTPE, 69007 Lyon, France
4
LPI, Houston, TX 77058 USA
5
GSC, Ottawa, ON K1A 0E4 Canada
1
Compiled U-Pb zircon ages of the oldest components of
the Acasta Gneiss Complex (AGC) on the western margin of
the Archean Slave Province [1] span 4.05-3.90 Ga [2-5]; even
older (4.2 Ga) ages [2, 3] have also been noted. AGC outcrops
cover a large (>50 km) area across several domal basement
antiforms, but only a small subset of these is documented. We
report ion microprobe conventional 2-D spot and 3-D depthprofile geochronology coupled with whole-rock (WR) and
zircon REE and Ti thermometry, in petrographic thin sections
and from mineral separates, of a diverse suite of AGC
lithologies including orthogneisses and gabbroic hornblende
schist enclaves. Samples were collected from photo-mapped
outcrops (1:25) to guide sampling. Discrete cm-scale gneissic
domains show distinctive [Th/U]zirc vs. [Ti]zirc temperatures
correlative with zircon U-Pb ages and rock compositions. We
used lattice-strain theory to model zircon/WR REE of zircon
domains (cores/rims) in different generations of gneisses and
relate these to ages of original igneous emplacement and
subsequent polyphase metamorphic histories. We confirm that
the earliest geological history of the AGC is at 4.2 Ga,
followed by magmatic incursions at mid-crustal depths (4.054.02 Ga) and thermal modifications at 3.96-3.85 Ga
concurrent with some lunar basin formation ages. Eoarchean
AGC ages (3.74-3.72) are also preserved, contemporaneous
with documented emplacement times for the 3.85-3.71 Ga
Itsaq Gneiss Complex in West Greenland [6] and 3.78-3.75 Ga
Nuvvuagittuq belt in northern Québec [7].
[1] St-Onge et al. (1988) Geol. Surv. Canada, Open Files
Report 1923. [2] Iizuka et al. (2006) Geology 34, 245–248.
[3] Bowring & Housh (1995) Science 269, 1535–1540.
[4] Iizuka et al. (2007) Precamb. Res. 153, 179–208. [5] Stern
& Bleeker (1998) Geosci. Canada 25, 27–31. [6] Nutman et
al. (1996) Precamb. Res. 78, 1–39. [7] Cates & Mojzsis
(2009) Chem. Geol. 261 98–113.
www.minersoc.org
1486
Goldschmidt Conference Abstracts
REE geochemistry of iron-apatite
deposits in Central Iran
Modelling of nanoparticles:
Aggregation of oxides and hydroxides
Geological survey of Iran, Exploration, Regional exploration
group ([email protected])
2
Czech geological Survey ([email protected])
Dept. of Chemistry, University of Bath, Bath, BA2 7AY, UK
(*correspondence: [email protected])
2
Dept. of Engineering and Applied Science, Cranfield
University, Shrivenham, SN6 8LA, UK
M.A.A. MOKHTARI1, M.H. EMAMI1, N. ABEDIAN1,
M. KHEZRI1 AND J. BABUREK2
1
REEs in different ore types display characteristic patterns,
related to different modes of formation of the ore. The apatites
of iron- apatite ores of Bafq region (Central Iran) show a
strong LREE/HREE ratio and a pronounced negative Eu
anomaly. This pattern is a distinct characteristic of igneous
apatites. Mentioned REE pattern is similar to that of apatites
from Kiruna iron ore and the other Kiruna- type iron ores in
elsewhere of the world.
In the all Iron-Apatite deposits of Central Iran, the REE
patterns of apatites, phosphate- bearing iron ores and iron ores
with no or very little phosphate, are similar and have a
different REE contents. This similarity indicates a common
source for these rocks and deposits. On the other hand, the
REE patterns of granitic intrusions which are located adjacent
to the iron-apatite ores have a similar REE patterns to that of
iron- apatite ores. This similarity, in turn, also indicates a
genetic relation for these rocks.
In general, it can be consider a basic alkaline magma rich
in iron and some incompatible elements such as P, REE, ThU, Cl and F, have been parent magma for Iron-Apatite ores
and granitic intrusions. This parent magma had been
differentiated into immiscible silicate- oxide- phosphate units
in route of ascend to the earth's surface.
M. MOLINARI1* D.C. SAYLE2 AND S.C. PARKER1
1
We use molecular dynamics simulations to study the
aggregation of CeO2 (ceria) and Mg(OH)2 (brucite)
nanoparticles (NPs). Calculations are running in vacuum and
in water in order to include the effect the solvent during
aggregation. We employ the DL_POLY code [1] and a
potential model fitted in the METADISE [2] and the GULP
[3] codes against ab initio data derived using the VASP code
[4]. We use ceria, an extended solid oxide, and brucite, a
layered material, as models. Forcing oriented aggregation
during the crystal growth of such important materials for
catalysis and sorption processes can facilitate the production
of tailor-made structures with enhanced properties.
The free energy change due to aggregation NPs can be
evaluated considering different interparticle orientations.
Results for 1ns run for ceria NPs in vacuum are shown in
Figure 1. The calculations predict no free energy barrier to
aggregation when the NPs approach along crystallographic
orientations as previously reported by Spagnoli et al. [5].
Finally, a comparison between aggregation in dry and wet
conditions is considered.
Figure 1: Free energy change of aggregation as a function of
distance for a 5nm diameter octahedral CeO2 NPs with a fixed
orientations: dashed line, approaching edges; solid line,
approaching faces.
[1] W. Smith, T.R. Forester, J. (1996) Mol. Graph. 14, 136.
[2] G. Watson et al. (1996) J. Chem. Soc. Faraday Trans. 92,
433. [3] J. Gale (1997) J. Chem. Soc. Faraday Trans. 93, 629.
[4] G. Kresse, J. Furthmuller (1996) Phys. ReV. B 54, 11169.
[5] D. Spagnoli et al. (2008) J. Phys. Chem. C. 112, 14731.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Direct pore-scale numerical
simulation of precipitation and
dissolution
S. MOLINS*, D.B. SILIN, D. TREBOTICH
AND C.I .STEEFEL
Lawrence Berkeley National Laboratory 1 Cyclotron Road,
Berkeley, CA 94720 USA
(*correspondence: [email protected], MS 90R1116)
([email protected], [email protected],
[email protected])
Mineral precipitation and dissolution driven by field
applications such as carbon sequestration or remediation
strategies can modify the geometry and structure of porous
media in relatively short time scales. In this context, feedback
processes between geochemical reactions and flow that take
place at the pore scale affect continuum scale parameters such
as permeability or reaction rates. Beyond the insights gained
by innovative experimental and imaging techniques such as xray computed micro-tomography, modeling provides a unique
tool to mechanistically understand and quantify these feedback
processes at the pore scale and inform continuum scale
models. In this work, we develop strategies to perform
efficient direct numerical simulation of flow and reactive
transport on idealized and complex pore scale geometries
building on existing platforms. We apply these approaches to
a range of pore geometries from single pores to 1-cm-long
columns to calculate average reactions rates and porositypermeability evolution and illustrate model capabilities and
limitations.
Simulations show that dissolution and precipitation
reactions affect the pore space nonuniformly. As a result, a
simple porosity-permeability correlation may be insufficient to
describe the complexity of the reaction-induced pore space
evolution. The relative magnitude of the reaction rate
constants affects the evolution of the permeability-porosity
relationship. In dissolution simulations, fast reactions result in
localized effects and further evolution of permeability is
relatively unaffected by subsequent porosity increase. In
contrast, slow reactions cause a less localized dissolution, with
the result that the permeability increase is consistent with the
porosity increment. Simulations show that in columns with the
same average parameters, including column porosity, reactive
surface area, and flow rate, different pore structures with
different flow patterns can result in different average reactions
rates.
Sequential coupling between transport and geochemical
reactions allowed us to use an efficient and flexible
computational fluid dynamics platform that implements
higher-order algorithms, while implicit coupling shows
promising results for efficient simulation of pore geometry
evolution. We discuss further model development for
interpretation of experimental results.
Mineralogical Magazine
1487
Genetic relation between Skarn ore
deposits and magmatic activity in the
Ahar region, Western Albuorz,
northwest of Iran: Evidence for
metasomatism and copper
mineralization
HABIB MOLLAEI AND RAHIM DABIRI
Department of Geology, Mashhad Branch. Islamic Azad
University, Mashhad -Iran. Office Phone No.: 0098
5118446361 ([email protected])
Numerous skarn deposits formed in the contact between
the Upper Cretaceous impure carbonate rocks and Oligocene–
Miocene Magmatic rocks in the Ahar region. The aim of this
study is to understand how magmatic activity led to the copper
skarn mineralization in this region. The history of skarn
formation starts with the emplacement and upwelling pluton
body, followed by the assimilation of limestone by the
magma. The skarnification process occurred mainly in two
stages: the first stage is starting with prograde metasomatism
and anhydrous minerals, this stage followed by four stages of
retrograde skarn deposit. In addition to Fe, Si and Mg,
substantial amounts of Cu, along with volatile components
such as H2S and CO2 were added to the skarn system.
Consequently considerable amounts of hydrous calc-silicates,
sulfides, oxides and carbonates replaced the anhydrous calcsilicates and the chemistry of the host granodiorites,
Mineralogical and chemical characteristic indicate that an
island arc or Subduction-related origin of Fe-Cu skarn deposit.
www.minersoc.org
Goldschmidt Conference Abstracts
1488
Thermodynamic models of aqueous
systems to high temperature and
concentration
REE in groundwater as indicators of
catchment lithology in semi-arid
regions
N. MOLLER* AND J.H. WEARE
Chemistry and Biochemistry, UCSD, San Diego, CA, 92093
(*correspondence: [email protected])
We have developed thermodynamic models, using the
Pitzer specific interaction equations, that describe interactions
as well as solid-liquid-gas equilibria to high temperature and
concentration within the H+, Na+, K+, Ca2+, Mg2+, Al3+, Al
(OH)2+, Al (OH)2+, Al (OH)30, Al (OH)41 Cl1, OH1, HSO4-,
SO42-, HCO3-, CO32-, Si (OH)4, SiO (OH)31, SiO2 (aq), CO2
(aq/g), H2S (aq/g), CH3 (aq/g), H2O system. In this
presentation, the construction of two models that produce
predictions with accuracy near the uncertainty of the
experiments is discussed. One, correctly calculates
solute/solvent activities and solid-liquid equilibria in the HNa-K-OH-Cl-HSO4-SO4-H2O system from dilute to high
solution concentration and from low to high pH within the 0°
to 250°C temperature range. The other correctly predicts
solvent/solute activities and monomeric aluminum hydrolysis
speciation as well as solid-liquid equilibria in the H+, Na+,
Al3+, Cl1, Si (OH)4, SiO (OH)31, OH1, Al (OH)2+, Al (OH)2+,
Al (OH)30, Al (OH)41 system as a function of pH to high salt
concentrations (I 8 5 m NaCl), for temperatures up to 300°C
and for saturation pressures. The latter model accurately
predicts the fluid compositions for the low Al (8 10-5 m) and
Si (OH)4 (8 10-4 m) concentrations commonly encountered in
the intermediate pH ranges typical of most natural fluids. For
high and low pH regions where the formation of polymeric Al
hydrolysis species is low, the model will apply to higher total
aluminum concentrations. The successful prediction of the
solubility of aluminiosilicate solid phases falling within this
system is also described.
Mineralogical Magazine
P. MÖLLER1, C. SIEBERT2 AND S. GEYER2
Helmholtz Zentrum Potsdam, Deutsches
GeoForschungsZentrum, D-14473 Potsdam
2
Helmholtz Center for Environmental Research-UFZ,
Halle/Saale 06120, Germany
1
REE in groundwater (GW) in regions with little soil
coverage characterize the lithology of its recharge area
because interaction of precipitation with soil coverage is short
to absent. Under such conditions the dissolution of minerals in
the catchment area becomes an important tool in particular in
regions with dominant transboundary GW flow in politically
unstable regions.
REE patterns in GW recharged over limestones resemble
those of the limestones. GW recharged over olivine bearing
basalts yield REE patterns that are controlled by dissolution of
the least stable minerals such as olivine and by scavenging
during weathering by ferric hydroxides and calcite. Bowlshaped REE patterns are typical. REE in GW from sandstones
are controlled by leachable minerals of their cements. In the
presences of gypsum and phosphates the intermediate REE are
enriched in GW.
REE in GW from aquifers of the same lithology of fthe
recharge area are controlled by strong sorption of REE onto
mineral surfaces. In case of limestones overlaying basalts the
GW from basalts shows nearly the same pattern as in GW
from the limestone above because the high REE abundance in
GW is adsorbed by minerals of the basalt and thus with time
GW passes the basalt without significant changes. In case of
basalts overlaying limestones the REE abundance in the final
GW is lower than expected from interaction with limestones.
Due to high Ca and Mg concentration from weathering of
plagioclase and olivine in basalts dissolution of calcite from
limestones is limited and thus the REE patterns achieved from
the basalt is not significantly altered during the passage of
limestone.
www.minersoc.org
Goldschmidt Conference Abstracts
Mineral textures and fluid inclusion
characteristics of ore samples from
the Guanajuato district, Mexico
Sulfide mineralogy of
West Greenland kimberlitic
mantle xenoliths
D. MONCADA* AND R.J. BODNAR
Dept. of Geosciences, Virginia Tech, Blacksburg, VA 24061
USA (*correspondence: [email protected], [email protected])
Successful exploration for mineral deposits requires tools
that the explorationist can use to distinguish between targets
with high potential for mineralization and those with lower
economic potential. In this study, we describe a technique
based on petrographic and fluid inclusion characteristics that
may be applied in exploration for precious metal deposits to
identify areas of high-grade mineralization.
The Guanajuato mining district in Mexico is one of the
largest silver producing districts in the world with continuous
mining activity for nearly 500 years. Ore shoots in the district
are localized along three major northwest trending vein
systems, the La Luz, the Veta Madre and the Vetas de la
Sierra. Mineralization in the district shows much variability
between and within individual deposits, from precious metalrich to more base-metal-rich zones, and from gold-rich to
silver-rich zones. Ore textures also vary and include void
space that formed during multiple fissuring events, banded
quartz veins, massive quartz veins and stockworks. More than
1, 200 samples representing all the different mineralization
styles were collected from all three vein systems in the
Guanajuato mining district, and the mineral textures and fluid
inclusion characteristics of each sample have been defined. In
addition, each sample was assayed for Au, Ag, Cu, Pb, Zn, As
and Sb.
Samples from the Guanajuato district show a wide range
in silica textures. Some of these textures, including colloform
texture, plumose texture and jigsaw texture, are indicative of
rapid precipitation, such as occurs when fluids boil. Other
mineral phases, including illite, rhombic adularia and bladed
calcite are also indicative of rapid growth in a hydrothermal
system and are characteristic of boiling systems. Because
boiling is an effective mechanism for precipitating gold and
silver from hydrothermal fluids, the presence of mineral
textures indicative of boiling is a desirable feature in
exploration. In many samples, textural evidence for boiling is
supported by coexisting liquid-rich and vapor-rich fluid
inclusions, or Fluid Inclusion Assemblages consisting of only
vapor-rich inclusions, suggesting ‘flashing’ of the
hydrothermal fluids. Textural and fluid inclusion evidence for
boiling has been observed in the deepest levels of the
Guanajuato mining district, suggesting that additional precious
metal resources may occur beneath these levels.
Mineralogical Magazine
1489
SISIR K. MONDAL1*, STEFAN BERNSTEIN2
2
AND MINIK T. ROSING
Department of Geological Sciences, Jadavpur University,
Kolkata-700032, India
(*correspondence: [email protected])
2
Natural History Museum of Denmark, University of
Copenhagen, 1350 Copenhagen, Denmark
([email protected], [email protected])
1
Sulfide minerals control the platinum group element
(PGE) budget of mantle rocks along with PGE behaviour
during melting and thus trace the Earth’s differentiation
processes. We have conducted mineralogical study of the
sulfide assemblages of mantle xenoliths sampled from two
West Greenland kimberlites dykes of presumed
Neoproterozoic age. One dyke from the Sarfartoq area, is
situated in 2.8 Ga continental crust, and part of the ca. 1.8 Ga
Nagsoqtoqidian mobile belt. The second kimberlite dyke
comes from the Aasivik terrain which represent early
Archaean, 3.5 to 3.7 Ga crust. The Sarfartoq- and Aasivikdykes can therefore be classified as Proton and Archon,
respectively. The xenoliths from the Sarfartoq kimberlite dyke
are relatively fresh but commonly contain pockets of finegrained magnetite, mica and hydrothermally altered silicates
interpreted to represent melts invaded from the kimberlitic
host. The Sarfartoq-dyke xenoliths are garnet-lherzolite
(olivine Fo 86.8-91.1), garnet-dunite (olivine Fo 90.1-91.2),
spinel-dunite (olivine Fo 91.4-93.0) and dunite (olivine Fo
89.2-92.5). Sulfide minerals are present as rounded blobs
mostly within olivine and rarely within garnet and
clinopyroxene. Minor amount of interstitial sulfide is also
present. Both types commonly occur in a single sample. Blobs
are dominated by pentlandite with minor chalcopyrite and
pyrrhotite and veined by late generated magnetite. The
xenoliths from the Aasivik kimberlite dyke are nearly all
extensively altered and appear to be mostly dunite (olivine Fo
87.8-92.5). Only relicts of olivine grains are present, and these
contain blobs of sulfides as inclusions. Our study suggests that
the sulfide was initially monosulfide solid solution, reequilibrated at low temperature.
www.minersoc.org
1490
Goldschmidt Conference Abstracts
The Pan-African reconstruction of
NW Angola: Petro-structural and
temporal constraints
P. MONIÉ1, D. BOSCH1, O. BRUGUIER1, A. VAUCHEZ1,
P. NSUNGANI1,2 AND Y. ROLLAND3
Géosciences Montpellier, UMR-CNRS-5243, Univ.
Montpellier 2, Place E. Bataillon, 34095 Montpellier,
Cedex 05, France ([email protected])
2
Agostinho Neto University, Avenida 4 de Fevereiro 7,
Luanda, Angola
3
Géosciences Azur, UMR 6526 CNRS, Université de Nice
Sophia Antipolis, Parc Valrose, 06108 Nice cedex 2 –
France
1
At the end of Neoproterozoic times, assembly of the
Gondwana supercontinent resulted in the closure of several
oceanic domains and accretion of large cratons. Various
tectono-metamorphic belts developed et the margins of these
cratons during the Panafrican orogeny. During this work, we
developed a study combining petro-structural and
geochronological investigations on the West Congolian belt
(NW Angola) resulting from the collision between the Congo
and Sao Francisco cratons. Two main tectono-metamorphic
units have been recognized in the studied area, namely eastern
and western internal units, and show a westward increase of
deformation and metamorphic grade. The WIU consists of
high-grade gneisses and migmatites with intercalation of
amphibolites, quartzites and pegmatites. This sub-unit
experienced metamorphic conditions that increase upward and
westward. Maximum P-T conditions for high-grade gneisses
have been estimated at 10-12 Kbar and 600-650°C. One garnet
amphibolite intercalated with gneisses has been dated and
yields ages of 539±7Ma and 498±5Ma for U-Pb and Ar-Ar
methods, respectively. A pegmatitic dyke concordant to the
regional foliation provides a concordant U-Pb age of
544±13Ma taken as our best estimate for pegmatite
emplacement. Two paragneisses have been also dated with
ages ranging from 589±12Ma to 678±48Ma suggesting a
detrital origine and indicating that detritus was derived from
Neoproterozoic source material. At least monazites from one
of this gneiss show a complex U-Pb age distribution (three
batches between 560-490Ma) and Ar-Ar biotite age of
487±5Ma. All this age underlines the predominance of the
Pan-African deformation and metamorphism in the
construction of this belt.
Mineralogical Magazine
Characterization of hyperalkaline
fluids produced by serpentinization
of mantle peridotites in Oman and in
Liguria (Northern Italy)
C. MONNIN*, V. CHAVAGNAC, G. CEULENEER,
C. BOULART AND G. HOAREAU
Geosciences Environement Toulouse, 14 Avenue Edouard
Belin, 31400 Toulouse, France
(*correspondence: [email protected])
High pH waters and gases produced by serpentinization of
mantle peridotites as well as precipitates forming at the
springs have been sampled between 2008 and 2011 in the
Semail nappe of the Oman Mountains and the Voltri group of
the Ligurian Alps (Northern Italy).
Factors influencing the composition of the hyperalkaline
waters are: 1) alteration of the ultramafic basement, 2)
formation of precipitates at the water discharge, 3) interaction
of the waters with the atmosphere, 4) mixing with surface
(runoff) waters, 5) concentration by evaporation.
In Oman the springs are located along major geological
discontinuities (Moho, basal contact between the ophiolite and
the underlying Cretaceous sedimentary formations).
The increase in the Na, K and Ca contents of the Oman waters
with chlorinity cannot be explained by evaporation, pointing
to the reactivity of these elements (formation of clays and Cacarbonates).
In Liguria, the alkaline springs are located above the river
beds and their waters do not mix with the river waters. In
Oman this mixing leads to a continuous range of pH from the
normal runoff (6 to 8) and the extreme values (12.1). In this
case, the pH change can be very rapid (dropping by two pH
units in half a meter at the site ‘Grande Ligurie’). Conversely
the pH drop of the alkaline waters collected in the irrigation
channels (falaj) is very slow, being due to the sole uptake of
atmospheric CO2.
Minerals forming at the springs are mainly calcite,
aragonite and brucite.
Larger values of the H2 content of the gas phase bubbling
at the springs are found in Oman while CH4 is more important
in Liguria.
The reaction of the infiltrating surface waters with the
ultramafic formation almost entirely removes the Dissolved
Inorganic Carbon indicating that the alteration of ophiolites is
indeed an efficient sink for carbon.
Our observations ask the question of the hydrologic
pathways of the water in ophiolites: percolation through the
ultramafic formation or circulation along major geological
discontinuities?
www.minersoc.org
Goldschmidt Conference Abstracts
Towards modelling biogenic
magnetite, Fe3O4
AMY MONNINGTON1, DAVID J COOKE1
2
AND COLIN L FREEMAN
Department of Chemical and Biological Sciences, University
of Huddersfield, UK ([email protected])
2
Department of Engineering Materials, University of
Sheffield, UK ([email protected])
1
There is an increasing number of new, exciting and
dynamic uses for magnetic nanoparticles (MNPs), including
many in the field of medicine (site-specific chemotherapy),
technology (spintronics) and industry (ferrofluids).
Magnetotactic bacteria produce chains of nanosized magnetite,
Fe3O4, particles that operate as internal magnets. This
biosynthesis of magnetite is the earliest known example of
biomineralisation, having first occured some two billion years
ago. Despite this, much of the detailed atomistic mechanism
by which the process occurs is unknown. Therefore, we have
begun to develop an atomistic model for the system, in an
attempt to understand the processes involved, particularly the
role of the 1-5% Co that is present in the biomineral.
In this work we report initial results for modelling the
different surfaces of magnetite, using differing methods.
Comparison of the related surface energies produced for these
methods, using energy minimisation (METADISE [1]) and
molecular dynamics (DL_POLY [2]), identified the {100}
surface as the most stable. For all methods, elasticity constants
were compared to the data produced from previous studies [3].
Subsequent to this, attachments of simple organic molecules to
the magnetite were analysed and modelling of interactions
between these molecules and the {100} surface were
performed.
Future work will validate the potentials for the interactions
between the simple organic molecules and the magnetite
surface, enabling us to fit the required organic/ inorganic cross
parameters to a system where the stable surfaces are well
defined, allowing us to better access the validity of each of the
components of the model. This is in the aim of progressing to
more complex protein attachments.
[1] Watson, G. W. et al. (1996) J. Chem. Soc. Faraday Trans.
92(3), 433. [2] Smith, W. & Forester, T. R. (1996) J. Mol.
Graphics 14(3), 136. [3] Doraiswami, M. S. (1947) Proc.
Math. Sci. 25(5), 413.
Mineralogical Magazine
1491
Neodymium isotopic composition of
gorgonian corals as reliable tool to
reconstruct water mass circulation
P. MONTAGNA1,2,3*, M. LOPEZ CORREA4, S. GOLDSTEIN2,
M.T. MCCULLOCH5, A. FREIWALD6, M. TAVIANI3,
J.A. TROTTER5 AND J. RADDATZ7
LSCE-CEA, 91198, Gif-sur-Yvette, France
(*correspondence: [email protected])
2
LDEO, Palisades, NY 10964, USA
3
ISMAR-CNR, Via Gobetti 101, 40129 Bologna, Italy
4
GeoZentrum Nordbayern, 91054 Erlangen, Germany
5
University of Western Australia, 6009 Crawley, Australia
6
Senckenberg am Meer, Abteilung für Meeresforschung,
D-26384, Wilhelmshaven, Germany
7
IFM-GEOMAR, D-24148 Kiel, Germany
1
It has recently been shown that intermediate and deep
ocean circulation can be reliably reconstructed using the
neodymium (Nd) isotopic composition of the aragonitic
skeleton of scleractinian deep-water corals [1,2,3,4].
Motivated by these findings, we have investigated the Nd
systematics of the high-magnesium calcite skeleton of deepwater gorgonian octocorals. These corals have centennialscale lifespans and are distributed worldwide, representing
potential archives of past oceanic circulation at sub-decadal
resolution. Live-collected corals, belonging to the families
Isididae (genus Keratoisis) and Coralliidae (genus
Corallium), were retrieved from the Atlantic, Pacific, and
Southern Oceans as well as from the Mediterranean Sea at
water depths between ~500 to ~1300m. Seawater samples
from two profiles in the Mediterranean Sea were collected at
the same locations and depths as the coral samples in order to
compare seawater Nd isotopic compositions with the coral
skeletons. The isotopic ratio (143Nd/144Nd) was obtained using
a VG Sector 54-30 thermal ionization mass spectrometer by
dynamic multicollection. The neodymium concentration was
analysed along different tracks parallel to the growth bands
using a 193nm laser ablation microsampling system connected
to a Varian 820 inductively coupled plasma mass
spectrometer.
The gorgonian calcite skeletons and the surrounding
seawater share equivalent Nd isotopic compositions, which
clearly show that these calcite corals are reliable archives of
water mass circulation.
[1] van de Flierdt et al. (2010) GCA 74, 6014-6032. [2] Copart
et al. (2010) QSR 29, 2499-2508. [3] Colin et al. (2010) QSR
29, 2509-2517. [4] Montagna et al. (2010) AGU meeting, San
Francisco.
www.minersoc.org
Goldschmidt Conference Abstracts
1492
OIB’s from South Eastern Pacific:
Notes from key geochemical features
Style and chronology of growth by
oblique accretion and oroclinal
bending: The Panama Isthmus
P. MONTECINOS MUÑOZ* AND K. PINTO LOGUERCIO
C. MONTES*1,2, A. CARDONA1,2, G.A. BAYONA2,
R. MCFADDEN1, S.E. MORON1, C.A. SILVA1,
S.RESTEPO-MORENO1 AND D.A. RAMIREZ1
Emilio Vaisse 332c, Santiago, Chile
(*correspondence: [email protected])
We summarize some geochemical features of basalts from
Easter, Juan Fernandez and Galapagos. Data were obtained
from GEOROC on March 2011. Elemental concentration were
normalized to primitive mantle displaying strong enrichment
for Juan Fernandez ([U]N~98, [Pb]N~49, [Th]N~40, [Nb]N~70,
[Ta]N~78) similar to EM2 source [1]. Easter and Galapagos
exhibit a moderately enrichment for Nb and Ta
([Nb]N~35,[Ta]N~50), and small enrichment for U, Pb, Th
([U]N~22,[Pb]N~9,[Th]N~17). These enrichment factors are
less than those for samples from EM and HIMU sources, and
the [U/Pb]N and [Th/Pb]N ratios of Easter and Galapagos are
different from EM and HIMU sources, suggesting that the
sources of the two islands contain Pb whose origins were not
explained by subduction-related process invoked for EM2 [1]
and HIMU [2].
That statement is supported by Pb isotopes plotted on a
206
Pb-normalized space (Fig. 1). In this plot a linear trend
composed by ~90% of Easter (Line e) is noticeable. Principal
component analysis calculation shows that Line e is an
eigenvector explaining a 94% of variability of Easter. Some
Easter samples are outside FOZO field [3] suggesting
influence from DM source and possibly other extreme
component located at left beyond FOZO. Azores samples
composing Az3 line (Fig.1) seems to confirm such extreme
component. Az1-Az2 lines go beyond Fozo field suggesting
another possible component different to HIMU and FOZO.
We thank to Professor Shun’ichi Nakai (University of
Tokyo) by his suggestions.
Smithsonian Tropical Research Institute, Box 0843-03092,
Balboa, Ancon Republic of Panama, ([email protected])
2
Corporación Geológica Ares, Calle 44a # 53-96, Bogotá,
Colombia
1
The Panama Isthums displays, in approximatley 500 km
(or ~15 Ma), the transition from: 1) ongoing subduction and
magmatism in a normal intra-oceanic arc setting; 2) a
deformed, exhumed and extinct magmatic arc, still in an
intraoceanic setting, and 3) an extinct arc accreted to a
continental margin. This west to east geographic progression
from active arc to accreted is also a proxy for the chronology
of this arc-continent collisions. The oblique accretion of the
Panama arc to northwestern South America is documented
with geologic mapping and multidisciplinary analytical
studies. A new geologic map with >2000 field stations, 40
petrographic analyses, 24 paleomagnetic sites, and over 30
new geochronological and thermochronological analyses,
supports the middle Miocene accretion of the Panama arc to
northwestern South America and a late Eocene initiation of
tectonic interaction. The extinct arc segment in central Panama
arc is composed of a folded-faulted, ~ 3 km-thick basaltic
sequence, intruded by granitoid bodies and onlapped by
mostly undeformed shallow marine and continental strata.
Existing geochronological data, and new whole-rock Ar/Ar
(2), and U/Pb zircon ages (6), reveal intense late Paleocene to
middle Eocene magmatism, a temporary cessation of
magmatic activity between 38 and 28 Ma, and renewed
magmatism after 28 Ma in a position approximately 75 km
south of the former magmatic axis in central Panama. The
geographic patterns of these magmatic pulses is interpreted as
a collison that left-laterally offset, and oroclinally bent the axis
of the arc, and terminated magmatic activity in the 28 to 38
Ma interval. Magmatic activity restarted after 28 Ma but lasted
only until ~15 Ma east of the Canal Basin and west of the
Uramita suture, defining an arc segment approximately 400
km in length that shows no sign of magmatic activity younger
than 15 Ma, probably the result of this part of the arc getting
detached and overthrusted the Caribbean Plate to the north.
The sigmoidal part of the Panama arc is therefore the result of
an extinct arc that has been obliquely accreting to the
northwestern margin of South America for the last 15 Ma.
[1] Jackson et al. (2008) Gcubed 9. [2] Hanyu et al. (2011)
Gcubed 12 . [3] Stracke et al. (2005) Gcubed 6.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Nucleation and growth of acicular
goethite from ferric hydroxide gel
under moderate temperature
(30 and 70°C)
G. MONTES-HERNANDEZ1*, P. BECK2, F. RENARD1,
E. QUIRICO2, B. LANSON1, R. CHIRIAC3
2
AND N. FINDLING
CNRS-UJF, Institute of Earth Sciences (ISTerre),
OSUG/INSU, BP 53, 38041 Grenoble Cedex 9, France
(*[email protected])
2
CNRS-UJF, IPAG, OSUG/INSU, BP 53, 38041 Grenoble
Cedex 9, France
3
Laboratoire des Multimatériaux et Interfaces UMR CNRS
5615, 43 bd du 11 novembre 1918, 69622 Villeurbanne
Cedex, France
1
The present study describes a simple and novel synthesis
route for sub-micrometric acicular goethite (+-FeOOH) using
high OH/Fe molar ratio (=5) and moderate temperature (30
and 70°C). Two different alkaline sources (NaOH and Ca
(OH)2) and two iron (III) sources (FeCl3.6H2O and Fe
(NO3)3.9H2O) were investigated. FESEM, XRD, FTIR, N2
sorption isotherms, colour evolution and pH monitoring have
been used to determine the formation mechanism, the particle
size, specific surface area, and morphology of goethite. Three
pH regions were determined during goethite formation and
each region was qualitatively associated to (I) the formation of
ferric hydroxide gel, leading to acid conditions (pH<2.5); (II)
spontaneous nucleation of goethite, leading to alkaline
conditions (pH>11) and fine sedimentable particles; (III)
growth of goethite in alkaline conditions (11<pH<13.5). The
kinetic behaviour depends clearly on the reaction temperature;
globally the nucleation-growth of goethite at 70 °C was about
three times faster than at 30 °C. For example, well-crystallized
goethite particles (high acicular goethite < 1µm in length with
moderate specific surface area, SBET=31.2m2/g) were produced
after 7h of reaction at 70 °C while about 24h of reaction are
required to produce well-crystallized goethite particles (low
acicular goethite < 0.5µm in length with high specific surface
area, SBET=133.8m2/g) at 30 °C using in both cases iron
chloride. In summary, the temperature and iron (III) source
have a significant effect on the particle size, specific surface
area and morphology of goethite. Herein, single-phase
goethite particles were formed. When Ca (OH)2 particles are
used as alkaline source, a complex mineral composite with
high specific surface area (87.3 m2/g) was synthesized; this
powdered material was mainly composed of unreacted Ca
(OH)2 coated by nanosized particles (possibly amorphous iron
hydroxide), calcium iron oxide chloride hydrate and calcite.
The best conditions to prepare uniform goethite particles,
possibly with high potential as adsorbents or pigments, have
been established.
Mineralogical Magazine
1493
Uncertainty assessment in
quantification of silicate weathering
rates in global rivers
SEULGI MOON1*, C. PAGE CHAMBERLAIN2
1
AND GEORGE E. HILLEY
Department of Geological and Environmental Sciences,
Stanford University, Stanford, CA 94305, USA
(*correspondence: [email protected],
[email protected])
2
Department of Environmental Earth System Science,
Stanford University, Stanford, CA 94305, USA
Department of Geology, University of California, Davis,
CA 95616 ([email protected])
1
Chemical weathering is important for understanding
landscape evolution, nutrient supply to ecosystems, and global
geochemical cycles. Total silicate weathering fluxes to oceans
have been quantified using compilations of catchment-wide
measurements of concentration and water discharge [1-3].
Sources of chemical elements were differentiated using
geochemical mass balance models (forward and inverse
models) to partition the fluxes of each of the measured
elements into carbonate, silicate, evaporite, and rain-water
pools.
In this research, we analyze time-series of elemental
concentrations and discharge from 52 global rivers provided
by the GEMS/Water compilation, which together constitute a
database of ~9000 data points. With these comprehensive
datasets, we estimate uncertainties within silicate weathering
rates in global rivers that consider the effects of infrequent
sampling, covariation between river discharge and
concentration, and uniqueness of attribution of weathering
fluxes to the different pools. This is accomplished using a
Bayesian Metrolpolis-Hastings algorithm to estimate the
overall uncertainties within, and covaration between
weathering fluxes that are attributed to the different pools
based on the GEMS/Water database. Knowing the overall
uncertainties in global estimates will provide information
about required sampling frequencies, number of sites, and
chemical elements that will help to design future catchmentscale studies.
[1] Gaillardet et al. (1999) Chem. Geol. 159, 3–30.
[2] Meybeck (2003) in Treatise on Geochemistry, Surface &
Ground Water, Weathering, & Soils, vol. 5, 207–223.
[3] Meybeck & Ragu (1997) UNEP Publication.
www.minersoc.org
Goldschmidt Conference Abstracts
1494
The origin of Darreh-Zanjir lead-zinc
Deposit, ‘Central Iran’
F. MOORE, E. SAJEDIAN, B. TAGHIPOUR
Department of Earth Science, College of Science, Shiraz
University, Shiraz, Iran
The Darreh-Zanjir Zn-Pb deposit is located 25 km southwest of Yazd province within Cenozoic magmatic belt of
central Iran. It occurs in the Lower Cretaceous dolomitized
limestones of Taft Formation and is underlained by Albian
shales of Biabanak Formation. A major fault known as
Darreh-Zanjir thrust fault is associated with minor faults and
trending east, north-east seems to control the mineralization.
This fault is also responsible for pushing Lower Cretaceous
carbonate strata over the older Albian shales. Cretaceous
dolomite formed by metasomatism of Lower Cretaceous
orbitolinous limestone, hosts the Pb-Zn mineralization.
The carbonated-hosted epigenetic mineralization consists
of primary galena and sphalerite and secondary carbonates
such as cerussite and smithsonite. The principal type of
mineralization is irregular, open space filling, forming vein
and stockworks. Two stages of mineralization are indicated.
The first being the dolomitization of limestone followed by
invasion
of
metal-bearing
hydrothermal
solutions.
Mineralization is confined to fault planes, fractures and their
margins. Several factors including geologic setting, lithology,
and hydrothermal solutions have played a role in the
mineralization. Minor faults and fractures have also provided
suitable conditions for secondary dolomitization and
mineralization. Field observations, mineralogy and
geochemical investigations show that Darreh-Zanjir Pb-Zn
deposit is a Mississippi Valley Type deposit.
[1] Report of GSI (1996) 96, 13-28.
Mineralogical Magazine
Natural attenuation of metal
contaminants in a large mineimpacted river: A long-term case
study of temporal and spatial trends
J.N. MOORE AND H.W. LANGNER*
University of Montana, Missoula, MT 59812-1296, USA
(*correspondence: [email protected])
We conducted a 20-yr study to determine environmental
trends in a mine-impacted watershed in Northwestern
Montana, USA. About 100 million tons of waste from copper
and precious metals mining were disposed of in the
headwaters of the Clark Fork River (CFR) between 1880 and
1982. Large amounts of contaminated material were
transported downstream and deposited on the floodplain,
where it acts as a secondary source of contamination to the
river. Our study focuses on spatial and temporal trends of As,
Cu, Cd, Pb and Zn in fine-grained bed sediments along a 200km river section below a set of tailings ponds that were
constructed to cut off the source of contaminants upstream.
Remediation in this section has been minimal, providing an
excellent area to study natural attenuation of contamination.
We collected monthly sediment samples from three locations
for most months between 1991 and 2010. In addition, four sets
of about 40 sediment samples were collected longitudinally in
1991, 1998, 2001 and 2009. The longitudinal concentration
profiles showed decreasing contaminant concentrations, with
temporal trends being less obvious than for monthly samples
at the three sites. Initial concentrations for As, Cd, Cu, Pb and
Zn at the most upstream monthly sampling site were 140, 8.3,
1400, 220, 1500 mg/kg, respectively, in 1991. Monthly
samples for all elements and sites trended down over time
following a first-order exponential decay model. However,
half-lives of sediment concentrations differed considerably
between elements, suggesting element-specific processes
affecting their transport and retention in the system. Half-lives
for Cd were 10 ± 0.5 yr for the three locations in the
watershed. Half-lives for Cu, Pb and Zn were 22 ± 5 yr, and
for As 35 ± 10 yr. Our monthly sampling also revealed high
variability without obvious relationships to seasonal or annual
variations of the hydrograph, showing that sediment sampling
in long intervals (e.g. annually) is insufficient to accurately
estimate trends. Our exponential ‘decay’ model predicts when
acceptable contaminant levels will occur without human
intervention. Thus, these results may assist with the selection
of cleanup strategies, for example where natural mixing and
transport processes may be preferable over engineering
approaches to remediation.
www.minersoc.org
Goldschmidt Conference Abstracts
The lower regolith boundary
revisited in unmatched detail with a
new global lithological map
NILS MOOSDORF, JENS HARTMANN
AND RONNY LAUERWALD
Institute for Biogeochemistry and Marine Chemistry,
KlimaCampus, University of Hamburg, Bundesstrasse 55,
20146 Hamburg, Germany ([email protected])
Bedrock is the lower boundary of the regolith column. It
represents one control on regolith formation. For this bedrock
types and properties are more relevant than its age, which
most geological maps focus on. A new high-resolution global
lithological map (GLiM) could provide a valuable tool for
global analyses of the regolith zone.
GLiM consists now of more than one million polygons
that were assembled from more than 65 geological maps;
some natively in digital format, some digitized by hand. Most
of the maps are at a scale of 1: 2, 500, 000 or finer. The
lithology information was gathered from metadata of the maps
or from additional literature, totalling more than 220 different
sources. The classification was expanded from the system
introduced by Dürr et al. [1, 2]. The map distinguishes six
classes of sediments, six classes of igneous rocks, as well as
metamorphic rocks. Additional information levels add further
detail (e.g. sediment grain size).
A presented comparison between maps of the uppermost
regolith layer (soil) and GLiM shows expected significant
spatial correlations between the lithological classes and soil
types. This highlights the impact of lithology on regolith
generation, which is one possible explaination of the impact of
lithology on chemical erosion3. Due to its high resolution, the
new global lithological map can be applied to numerous global
problems that require high levels of detail.
[1] Dürr, H. H. Meybeck, M. & Dürr, S. H. (2005) Global
Biogeochemical Cycles 19, GB4S10. [2] Moosdorf, N.
Hartmann, J. & Dürr, H. H. (2010) Geochem. Geophys.
Geosyst. 11, Q11003. [3] Hartmann, J. Dürr, H. H. Moosdorf,
N. Meybeck, M. & Kempe, S. (in press) International Journal
of Earth Science.
Mineralogical Magazine
1495
Organic nitrogen cycling during
organic matter decomposition
M. MOOSHAMMER1*, W. WANEK1, A.H. FRANK1,
F. HOFHANSL1, K.M. KEIBLINGER2,
S. ZECHMEISTER-BOLTENSTERN2 AND A. RICHTER1
Dept. of Chemical Ecology and Ecosystem Research,
University of Vienna, 1090 Vienna, Austria
(*correspondence: [email protected])
2
Federal Research and Training Centre for Forests, Natural
Hazards and Landscape, BFW, 1131 Vienna, Austria
1
Proteins represent the dominant input of organic N into
soil ecosystems. The breakdown of proteins to amino acids is
anticipated to be the critical process determining the
underlying mechanisms in litter and soil N dynamics. This
includes initiating the N mineralization sequence by providing
substrates for ammonification and microbial uptake. However,
the release and fate of organic N-containing compounds
during decomposition of organic matter is largely unknown.
We developed a new 15N pool dilution assay to quantify
gross rates of protein depolymerization (i.e. amino acid
production) and amino acid immobilization [1]. The assay is
based on the concurrent labeling of the pool of 18
proteinogenic amino acids, which are present in a free form in
soil and litter, and the measurement of 15N:14N ratios in the
individual amino acids by GC-MS over time.
The results from a litter decomposition experiment
showed that gross protein depolymerization exceeded gross N
mineralization by >8 fold indicating that only a small fraction
of amino acids released by extracellular enzymes was actually
mineralized to ammonium. These results point to an important
direct role of dissolved organic N (i.e. amino acids) for
microbial N nutrition and a negligible contribution of MIT
(‘mineralization-immobilization
turnover’;
extracellular
deamination of amino acids) to N mineralization in
decomposing litter. Furthermore, controls such as litter quality
and microbial community structure and the effect of stress (i.e.
temperature) on organic and inorganic N cycling processes
will be discussed in more detail.
[1] Wanek et al. (2011) Soil Biology & Biochemistry 43, 221–
221.
www.minersoc.org
1496
Goldschmidt Conference Abstracts
Synthesis of magnetite nanoparticles
and using them for separating toxic
elements from the wastewater of
sulphuric gold mines
M.A. MORADIAN1, M.O. MORADIAN2,
3
AND Z. BOROUMAND
NanoBioEarth Group, Applied Research Center of Geological
Survey of Iran ([email protected])
2
Chemistry faculty of Kashan University
([email protected])
3
NanoBioEarth Group, Applied Research Center of Geological
Survey of Iran ([email protected])
1
Arsenic is a toxic element that the maximum allowable
concentration for it in drinking water is about 0.5
mg/lit. Arsenic Inorganic compounds include As2O3, FeAsS,
AsS and As2S3. Although arsenic has a multi allotrope element
with yellow, gray and black colors, but only the gray ones that
are solid metalloid, crystalline and fragile, are persistent in the
nature. Approximately 100, 000 tones arsenic are produced
per year in the world because of excavating metals such as
copper, lead, cobalt and gold. It causes cancer because of
impairing synthesis of DNA and RNA.
One of the most essential problems in Zarshouran gold
mine, in northwest of Iran, is existence of too much arsenic in
wastewater of mining. Different methods are presented to
remove arsenic from the wastewaters such as: Arsenic can be
removed by composite of graphene oxide and ion exchange
method, but these methods are so high expense that has
limited using them. We prepared magnetic nanoparticles with
different methods in laboratory. These nanoparticles were less
than 50 nanometers in diameter that we used it for removing
arsenic as a very light expense method from Zarshouran
wastewaters. A natural bond creates between arsenic and
magnetic nanoparticles. After separating of arsenic,
nanoparticles can be separate from the solution with a simple
magnet. We succeed to remove arsenic with over 99 percent in
volume by this method.
Mobility of nitrogen and heavy
metals in biosolid amended soil
D. MORAETIS*, S. VOUTSADAKI, M. KOTRONAKIS,
G. KONTOLAIMAKIS1, F.E. STAMATI, N.P. NIKOLAIDIS
AND N. KALOGERAKIS
Technical University of Crete, Chania 73100 Greece
(*correspondence: [email protected])
The potential leaching and availability of nitrogen and
heavy metals in biosolid-amended soil were investigated using
batch and column studies. The mobility of heavy metals were
assessed with SPLP and TCLP tests while the availability of
nitrogen with a KCl extraction test. In addition semicontinuous column studies were conducted to assess the
leachability of nitrogen and heavy metals from biosolidamended soil under simulated-unsaturated soil conditions. One
type of biosolids, a compost derived from municipal solid
waste recycling of the organic fraction together with a clayey
soil typical of Crete were used in this study. Two application
rates of 100 and 200 t/ha were tested. The results were
compared with soil lysimeter measurements of a parallel
experiment in an olive grove.
Results
The total input of N was 1160 and 2320kg/ha for the two
amendments. KCl extraction showed that 15 and 96 kg/ha of
N (N-NO3+N-NH4) was bio-available which correspond to
1.3% and 4.2% of the total N input for the 100 and 200t/ha
application rates respectively. Columns packed with soil
amended with 200t/ha compost and receiving synthetic rain
released 34 kg/ha of N (N-NO3+N-NH4). Using lysimeter
measurements the average release of N in olive grove compost
amended soil was estimated to be 16kg/ha N. The results from
all measurements were consistent.
Heavy metal mobility from compost-amended soil was
assessed with the SPLP and TCLP batch tests, semicontinuous column studies and field measurements with
lysimeters. All results were consistent and orders of magnitude
lower than EPA standards [1]. Zn was shown to be the most
mobile metal in all measurements. Results suggest that onetime application of biosolids at agronomic rates will not
impact the groundwater.
[1] EPA (1996) Soil Screening Guidance, Document 540/R96/018.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Long-distance transport of North
Gondwana Cambro-Ordovician
sandstones: Evidence from detrital
zircon Hf isotopic composition
NAVOT MORAG1*, DOV AVIGAD1, AXEL GERDES2,
ELENA BELOUSOVA3 AND YEHUDIT HARLAVAN4
Institute of Earth Sciences, The Hebrew University of
Jerusalem, Jerusalem 91904, Israel
(*correspondence: [email protected])
2
Institut für Geowissenschaften, Johann Wolfgang Goethe
Universität, D-60438 Frankfurt am Main, Germany
3
GEMOC, Department of Earth and Planetary Sciences,
Macquarie University, NSW 2109, Australia
4
The Geological Survey of Israel, Jerusalem 95501, Israel
1
A voluminous Early Paleozoic sequence of quartz-rich
sandstones was deposited in northern Gondwana following its
assembly during the Neoproterozoic-Cambrian Pan-African
Orogeny. Field evidence for the sense of transport indicate
that sediments were carried from Gondwana hinterland
towards the supercontinent margins in the North (present
coordinates). Derivation from Pan-African terranes is evident
from the ubiquity of detrital zircons with Neoproterozoic U-Pb
ages, but the exact provenance of these siliciclastic deposits
remains unclear. Herein we present new Hf isotopic data from
U-Pb dated detrital zircons of the Cambro-Ordovician
sandstone that top the juvenile Neoproterozoic basement of
the Arabian-Nubian Shield in Israel and Jordan. Remarkably,
the detrital zircon Hf isotopic signal stands in marked contrast
with Nd and Hf isotopic signature of the underlying basement.
A preponderance (61%) of the Neoproterozoic-aged detrital
zircons from the Cambro-Ordovician sandstones in Israel and
Jordan yielded negative 0Hf(t) values incompatible with a
juvenile source. Therefore, rather than from the adjacent
Arabian-Nubian Shield, most of the detrital zircons were
derived from distant terrane(s), comprising preNeoproterozoic crust reworked during Pan-African orogeny.
Because our sampling sites are situated at the northern tip of
the Arabian-Nubian Shield, sand must have been transported
several thousand kilometers before deposition. This finding
also implies that the Arabian-Nubian Shield and other PanAfrican orogens of NE Africa were completely warned down
by the onset of Cambro-Ordovician deposition and that vast
areas in the northern part of Gondwana were then low-lying
such as to allow transfer of sand across the continent.
Mineralogical Magazine
1497
Macroscopic anhydrite interacted
with Pb-doped solutions
JUAN MORALES1, J.M. ASTILLEROS1,2, AMALIA JIMÉNEZ3.
AND L. FERNÁNDEZ-DÍAZ1,2
Dpto. Cristalografía y Mineralogía. Universidad Complutense
de Madrid. 28040 Madrid. Spain
2
Instituto de Geociencias (UCM-CSIC). 28040 Madrid, Spain
3
Facultad de Geología de la Universidad de Oviedo, 33005,
Oviedo, Spain
1
Pb is a toxic metal that affects the vital functions of living
organisms. A previous study showed that Pb sorption by
gypsum is an effective uptake mechanism [1]. Here the ability
of anhydrite to uptake Pb from aqueous solutions is evaluated
and its effectiveness as Pb-remover compared with that of
gypsum. Experiments were performed by placing 2g of
crushed pure anhydrite in 100 mL of Pb-bearing aqueous
solutions (ranged from 10 to 1000 mg/L) and, after specific
reaction periods (1 minute to 5 weeks), analyzing the aqueous
solution and examining the solids formed on the surface of the
anhydrite crystals. DRX data revealed that anglesite formed on
anhydrite after short interaction periods (Figure 1). ICP-OES
analyses showed that when the initial Pb concentration,
[Pb]ini, was % 50 ppm, it decreased very rapidly to reach a
constant value (A 5 ppm) after about six hours. The evolution
of the solution composition is consistent with a coupling
between anhydrite dissolution and anglesite precipitation. Our
results indicate that anhydrite and gypsum surfaces have
similar ability to remove Pb from aqueous solutions.
Figure 1: SEM images of anhydrite surface after interaction
with a Pb-bearing aqueous solution ([Pb]ini =100ppm). (A)
BSE image showing the distribution of anglesite crystals
(bright spots) formed on anhydrite surface after 5 minutes
interaction. (B) After a 24 hours interaction period of anglesite
reach sizes in the range 3 to 10 microns.
[1] J.M. Astilleros et al. (2010) Applied Geochemistry 25(7),
pp. 1008–1016.
www.minersoc.org
1498
Goldschmidt Conference Abstracts
Partitionning of Pt-Re-Os between
solid and liquid metal in the Fe-Ni-Si
system
G. MORARD1,2, J. SIEBERT1,2, D. ANTONANGELI1,2
1
AND J. BADRO
1
2
Institut de Physique du Globe de Paris, France
Institut de Minéralogie et de Physique des Milieux
Condensés, Paris, France
The Earth evolved into a layered body early in its history
with silicates and oxides forming the mantle while molten
metal was gravitationally segregated to form the core. Cooling
of the Earth causes the liquid core to crystallize. In the
meantime, small amount of liquid outer core material could be
remixed by dynamical entrainment in the deep mantle. This
mechanism was proposed as responsible for the Os isotopic
anomalies observed in some mantle-plume derived lavas
(OIBs). In that model, a radiogenic Os signature would be
produced in the outer core as a result of inner core
crystallization, and would then be remixed with the mantle
and imprint the isotopic composition of some OIBs.
Here we investigate the solid-liquid fractionation of Os,
Re and Pt in the metal at high pressure. As these partition
coefficients depend on metal composition, we choose to study
the most realistic candidate for core composition, the Fe-Ni-Si
system, for which no data exist so far.
He-Pb lead evidence for marble cake
under the Pacific-Antarctic ridge
M. MOREIRA1*, C. HAMELIN1 AND L. DOSSO2
Institut de Physique du Globe de Paris, Sorbonne Paris Cité,
CNRS (UMR 7154), 1 rue Jussieu, 75238, Paris Cedex,
France (*correspondence: [email protected])
2
CNRS, UMR6538, Domaines Océaniques, IFREMER,
B.P.70, 29280 Plouzané, France
1
Lead isotopes and Helium isotopes were analyzed in glass
samples from 10 seamounts located off-axis of the PacificAntarctic Ridge between 50.5°S and 41.5°S. Samples were
dredged during the Pacantarctic 2 cruise of the R/V L’Atalante
in Dec. 2004-Jan. 2005. Helium isotopic ratios vary between
the local mean MORB value (4He/3He=95, 300; R/Ra=7.58)
and more radiogenic values (4He/3He=182, 460; R/Ra=3.96)
associated with high He abundances (~10µccSTP/g). The
206
Pb/204Pb ratio goes up to 20.2. 4He/3He ratio and 206Pb/204Pb
ratios are correlated in samples from the pacific ridges [1] and
off-axis seamounts (figure). Clearly, this correlation between
helium and lead isotopes reflects the marble-cake structure of
the mantle where the fertile component carries the radiogenic
signatures. Because of a thicker off-axis lithosphere, this
fertile component is more likely to be sampled off-axis as it
melts preferentially to the peridotitic mantle.
[1] Hamelin et al. (2011) Earth & Planetary Science Letters
302, 154–162.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
A geochemical approach to the Sado
saltmarshes (Portugal)
The plumbing system of the Ischia
island: A physico-chemical window
on the fluid-saturated and CO2sustained Neapolitan volcanism
(Southern Italy)
S. MOREIRA1*, M.C. FREITAS1, C. ANDRADE1
2
AND M.F. ARAÚJO
Universidade de Lisboa, Faculdade Ciências, Departamento
de Geologia & Centro de Geologia, 1749-016 Lisboa,
Portugal (*correspondence: [email protected])
2
Instituto Tecnológico e Nuclear, EN 10, 2686-953 Sacavém,
Portugal
1
The Sado estuary develops ca. 20 km south of Lisbon and
studies of its subtidal and intertidal sediments, (namely of
marginal marshes - Malha da Costa, Faralhão, Carrasqueira,
Alcácer) showed that upper estuarine (Alcácer) sediments
yield a Zn/Al-normalized ratio up to 14x (channel) and 7x
(marsh) higher than in all remaining areas [1, 2]. Zn is sourced
in the Iberian Pyrite Belt terranes - exploited for ore since the
Calcolithic - which are intersected by the Sado’s watershed;
weathering and lixiviation of waste-piles input inorganic
carriers of Zn into the drainage system, the metal progressing
downstream until reaching the high-salinity upper estuarine
domain.
This motivated the sedimentological and geochemical
study of a 2.7 m-long core taken from the Alcácer saltmarsh,
to investigate the variatons in Zn and other heavy metals along
time. The core consists of a monotonous accumulation of
muddy sediment (coarse fraction <8%), with compatible
values of Si (26-28%) and Al (~9%), high in organic matter
(~7-10%) and CaCO3-free, thus low (<0.5%) in Ca.
The vertical profiles of terrigenous elements are fairly
invariant. K (1.7-1, 9%) and Ti (0.5-0.6%) usually associate
with Al-silicates, and may be replaced by Rb (145-157 mg/kg)
and Zr (129-161mg/kg), respectively, in those minerals; these
elements and Al present identical vertical variation profiles.
The elemental content in Zn decreases upcore (3200 to
443mg/kg) and the Al-normalized values range between
50J10-4 and 365J10-4. The lowermost 6 cm of the core yielded
Zn/Al >100J10-4. The contents of Cr, Ni, Cu and Pb are 95153, 41-59, 91-228 and 44-73mg/kg, respectively. The vertical
variation of the Al-normalized values of these metals show a
slight increase of Cr and Pb upward and a clear decrease in Ni
and Cu in the top meter.
The closure of several mines and rehabilitation of tailing
areas should have decreased the supply of Zn to River Sado
tributaries, and consequently in the lower reaches of the river.
At this point it is not possible to indicate the factor responsible
for the increment of Cr and Pb to the surface.
R. MORETTI1,2, I. ARIENZO2, G. ORSI2, L. CIVETTA2,3
4
AND M. D’ANTONIO
Dipartimento di Ingegneria Civile, Seconda Università di
Napoli, Aversa (CE), Italy
2
INGV-Osservatorio Vesuviano, Via Diocleziano 328, Napoli,
Italy
3
Dipartimento di Scienze Fisiche, Università di Napoli
“Federico II”, Napoli, Italy
4
Dipartimento di Scienze della Terra, Università di Napoli
“Federico II”, Napoli, Italy
1
Ischia, a small island located 18 miles NW offshore
Naples (Southern Italy), is a densely populated active caldera
(last eruption 1302 A.D.). Melt inclusions in phenocrysts of
poorly differentiated eruptive products constrain structure and
nature of the Ischia deep magmatic feeding system. Volcanic
products bear clear evidence for CO2-dominated gas fluxing,
under very oxidized conditions, and CO2 enrichment in
magma portions stagnating at major crustal discontinuities.
Volatile concentrations require gas-melt equilibria between 3
and 18 km depth. At Ischia there is much less magma than that
needed to directly supply the amount of released magmatic
fluid. Comparison with data from the other nearby Neapolitan
volcanoes (Procida, Campi Flegrei –CF-, and SommaVesuvius –SV-) highlights the pivotal role of deep fluids in
originating the volcanism. Despite the compositional and
eruptive style differences observed within the small extension
of the Neapolitan Volcanic District, and the variable
occurrence of mixing, crustal assimilation and fractional
crystallization, the different kinds of volcanism are mostly
linked by supercritical CO2 fluids produced by the
devolatilization
of
subducted
terrigenous-carbonatic
metasediments. Geochemical and isotopic differences among
Ischia, CF and SV from one side, and Procida from the other
one, reflect the tectonically controlled slab-derived fluids
release and upraise trough the mantle wedge, that, in turns,
control magma generation.
[1] Cortesão & Vale (1995) Mar Pollut Bull 30, 34–37.
[2] Moreira et al. (2009) J Coastal Res SI 56, 1380–1384.
Mineralogical Magazine
1499
www.minersoc.org
1500
Goldschmidt Conference Abstracts
Climatic conditions during the
Holocene based on Levantine
continental shelf sediment cores
T. MOR-FEDERMAN1, R. BOOKMAN1*,
A. ALMOGI-LABIN2 AND B. HERUT1,3
Dept. of Marine Geosciences, Charney School of Marine
Sciences, University of Haifa, Mt. Carmel, Haifa 31905,
Israel (*correspondence: [email protected])
2
Geological Survey of Israel, 30 Malkhe Israel, Jerusalem
95501, Israel
3
Israel Oceanographic & Limnolological Research, Tel
Shikmona, Haifa 31080, Israel
1
Sediments deposited on the southeastern continental shelf
of the Levantine Basin are sensitive recorders of climatic and
oceanographic variability affected by the north Atlantic and
indirectly by monsoonal systems. In order to reconstruct the
influence of these climatic systems on Holocene sediments
two cores were taken off shore the southern (V115) and
central (V101) Israeli coast at water depths of ~35 m. The
cores, dated to 7, 630 and 8, 440 14C years BP, show two
distinct sedimentation regimes. High rates, of 190-140 cm/ka,
in the lower Holocene, and significantly lower rates of 50-60
cm/ka during the last 5, 500 years. The cores were analyzed
for grain size, TOC, "13C, major and trace elements, and Sr
isotopes. Selected results are shown in the figures below. The
full data set indicates clearly that two distinct climatic periods
governed the eastern Mediterranean and its surroundings
during the Holocene.
Timescales of eruption triggering and
magma transport from element
diffusion in minerals
DAN MORGAN*
School of Earth & Environment, University of Leeds, LS2 9JT
UK (*correspondence: [email protected])
Mixing of magmas of contrasting temperatures and
compositions can act as a trigger of a subsequent volcanic
eruption. Heating of a magmatic system by basaltic injection
can remobilise magma that is close to its solidus, and mixing
can further change the character of the magma, lowering
viscosity and promoting eruption.
Upon mixing, if the magma system remains saturated in
mineral phases inherited from one or both parental melts,
strongly-zoned mineral grains will form, as a product of
changes in mineral-melt equilibria and melt composition.
Subsequent residence at magmatic temperatures will allow
such abrupt chemical zoning profiles to relax by diffusion. If
magma temperatures are known, we can place constraints on
diffusion time and thereby investigate the amount of time that
passes between a magma injection – ultimately our eruption
trigger – and the ensuing eruption.
Study of large silicic systems implies crystal residence
times at magmatic temperatures of the order of tens of years
(e.g. Whakamaru Ignimbrite, NZ, [1]) to thousands of years
(e.g. Fish Canyon Tuff, USA, [2]), which is still relatively
rapid given the large volumes concerned. Looking at smaller
systems, the Nea Kameni Dacite of Santorini suggests a
remobilisation time of the order of a month between basaltic
injection and dacite eruption [3], whilst study of the recent
Eyjafjallajokull eruption of 2010 resolves multiple mixing
events occurring in the months prior to, and during, the
eruption. In contrast, work on Piton de la Fournaise volcano is
less clear-cut, and perhaps sounds a cautionary note for
determining magmatic timescales from diffusion profiles.
Developments of new software tools and methodologies,
and the utilisation of new mineral-element systems promise an
expansion of these techniques. However, the petrological
context has to be a major concern in these studies as it entirely
determines the significance of the results.
[1] Saunders, Morgan, Baker & Wysoczanski (2010) Journal
of Petrology 51, 2465–2488. [2] Charlier, Bachmann,
Davidson, Dungan & Morgan (2007) Journal of Petrology 48,
1875–1894. [3] Martin, Morgan, Jerram, Caddick, Prior &
Davidson (2008) Science 321, 1178.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Rapidly assessing changes in bone
mineral balance using natural stable
calcium isotopes
J.L.L. MORGAN1*, G.W. GORDON1, S.J. ROMANIELLO1,
J.L. SKULAN2, S.M. SMITH3 AND A.D. ANBAR1
Arizona State Univ., Tempe, AZ 85287
(*correspondence: [email protected],
[email protected], [email protected],
[email protected])
2
Geology Museum, Univ. of Wisconsin, Madison, WI 53706
([email protected])
3
HACD, NASA Johnson Space Center, Houston, TX 77058
([email protected])
1
We demonstrate that variations in the Ca isotope ratios in
urine rapidly and quantitatively reflect changes in bone
mineral balance. This variation occurs because bone formation
depletes soft tissue of light Ca isotopes, while bone resorption
releases that isotopically light Ca back into soft tissue.
In a study of 12 individuals confined to bed rest, a
condition known to induce bone resorption, we show that Ca
isotope ratios shift in a direction consistent with net bone loss
after just 7 days, long before detectible changes in bone
density occur. Consistent with this interpretation, the Ca
isotope variations track changes observed in N-teleopeptide, a
bone resorption biomarker, while bone-specific alkaline
phosphatase, a bone formation biomarker, is unchanged. Ca
isotopes can in principle be used to quantify net changes in
bone mass. Ca isotopes indicate an average loss of 0.62 ± 0.16
% in bone mass over the course of this 30-day study. The Ca
isotope technique should accelerate the pace of discovery of
new treatments for bone disease and provide novel insights
into the dynamics of bone metabolism.
Bone Formation
Bone Resorption
[1]
Figure 1: Change in Ca isotope ratios of urine as a result of
bed rest.
[1] Skulan et al. (2007) Clinical Chem. 53, 1155–1158.
Mineralogical Magazine
1501
Improving the accuracy of the
40
Ar/39Ar geochronometer
L.E. MORGAN1*, D.F. MARK2, K.F. KUIPER1,
O. POSTMA1, I.M. VILLA3 AND J.R. WIJBRANS1
Faculty of Earth & Life Science, Vrije Universiteit, De
Boelelaan 1085, 1081HV, Amsterdam, The Netherlands
(*correspondence: [email protected])
2
NERC Argon Isotope Facility, Scottish Univ. Environmental
Research Centre, East Kilbride, G75 0QF, UK
3
Universität Bern, Institut für Geologie, Baltzerstrasse 3, CH3012 Bern, Switzerland
1
The accuracy of the 40Ar/39Ar system relies on a number of
parameters, most notably decay constants for the branched
decay of 40K to 40Ar and 40Ca, and the 40Ar/40K ratios (or ages)
of mineral standards used as neutron flux monitors.
Although these parameters can be assessed to an extent
through intercalibration efforts (e.g. [1]), a serious effort to
better constrain these parameters based on metrologically
traceable measurements, modern technologies, and rigorous
uncertainty analyses is overdue [2, 3, 4].
Here we present steps towards a ‘first principles’
calibration of the 40Ar/39Ar system by measurement of 40Ar
and 40K concentrations. These measurements will be used both
to determine the 40Ar/40K ratios of mineral standards (thus
allowing for calculations of their K-Ar ages) and also the 40Ar
branch of the 40K decay constant via ingrowth experiments in
material enriched in 40K.
40
Ar concentration measurements are based on sensitivity
corrections via a calibrated pipette system working under the
principles of the ideal gas law. This system relies on
components with calibrations traceable to international
standards and will be both renewable, with a lifetime of ca. 1
month for gas in the reservoir, and portable, to permit
interlaboratory calibrations.
40
K concentration measurements are based on TIMS
measurements and NIST standard reference materials for
elemental (SRM999b) and isotopic (SRM985) potassium.
This series of measurements aims to directly calibrate the
40
Ar/39Ar system using measurements traceable to
international standards, similar to recent steps taken by the
U-Pb community [6].
The research leading to these results has received funding
from the European Community's Seventh Framework
Programme (FP7/2007-2013) under grant agreement n°
215458.
[1] Kuiper et al. (2008) Science 320, 500–504. [2] Min et al.
(2000) GCA 64, 73–98. [3] Begemann et al. (2001) GCA 65,
111–121. [4] McDougall & Wellman (2010) Chem.Geol. 280,
19–25. [6] Condon et al. (2010) GCA 74, 7127–7143.
www.minersoc.org
1502
Goldschmidt Conference Abstracts
Two pyroxene-garnet rock of the
Gridino area of Belomorian mobile
belt (Northern Karelia), Karelia,
Russia: Record of the prograde and
retrograde metamorphic events
A.A. MORGUNOVA1* AND A.L. PERCHUK1,2
Institute of Experimental Mineralogy, Academica Osipyana
Street 4, Moscow distr. 142432, Chernogolovka, Russia
(*correspondence: [email protected])
2
Lomonosov Moscow State University, Geological Faculty,
GSP-1, Leninskie Gory, Moscow, Russia
([email protected])
1
Archean felsic gneisses in the high pressure Gridino
complex host lenses boudins and dikes of eclogitized mafic
(gabbro, gabbro-norite) and ultramafic (garnet-pyroxene rock,
orthopyroxenite) rocks. The paper is aimed to reconstruct
metamorphic evolution of the two pyroxene-garnet rock forms
a boudin of size 4*5 m in the amphibole-biotite gneisses on
the Visokii Island of the White Sea.
The early episode of the rock evolution is characterized by
inclusions of calcite and diabantite (rare Fe-Si chlorite). The
diabantite is well-known as product of metasomatic alteration
of peridotites. Inclusions of this mineral were found in all
rock-forming minerals (garnet, clino- and orthopyroxene).
They often associate with REE and U, Th-rich minerals, which
tend to crystallize at the walls of the vacuoles. The inclusions
are very unusual in term of the surrounding cracks. The
inclusions hosted by pyroxenes are surrounded by the both
concentric and radial cracks, whereas inclusions in garnets are
surrounded by the only radial cracks. Theses features indicate
that the inclusions have been recrystallized after their trapping.
Thermobarometric study of the rock indicates that unhydrous
mineral assemble garnet+clinopyroxene+orthopyroxene that
replaced diabantite-bearing metasomatic rock was formed
under T-P conditions (690LM/1.7 GPa) of eclogite facies
similar to those determinated for the Archean mafic eclogites
within the complex. Rim zones of the rock-forming minerals
indicate isothermal decompression down to & ~ 1.2 GPa,
followed by the episode of cooling to T ~ 650LM and
decompression to & ~ 0.9 GPa recorded by development of the
retrograde amphibole-garnet-orthopyroxene association [1].
Dispersal of tritium and 3He along the
outer rim of the Weddell gyre
R. MORIARTY*, Z. ZHOU AND C.J. BALLENTINE
SEAES, University of Manchester, M13 9PL, UK
(*correspondence: [email protected])
Weddell gyre plays an important role in the southern
closure of the Meridional Overturning Circulation (MOC) and
in the ventilation of the deep ocean through the formation of
Antarctic Bottom Water (AABW). Estimates of AABW
production in the region are not very well constrained and
range between 3 and 11Sv (1Sv=106 m3 s-1)[1]. Recent
observations [2, 3] suggest that the Weddell gyre may not be
the primary region of AABW formation as previously thought.
Exchange between the Weddell gyre and the world oceans
occurs at the outer rim of the gyre. Determination of the
transport of water masses across this boundary is needed to
quantify the production and export of AABW in and from the
gyre and to determine its contribution to global ocean
circulation.
Seawater samples (~500) for tritium and helium-3 analysis
were collected along the outer rim of the gyre as part of
ANtarctic Deep Rates of EXport (ANDREX) project between
(Dec. 2008 and April 2010). These samples covered 48
stations and ranged from suface to a depth of 6000m. Helium3 values in conjunction with another steady state tracer, PO4*,
will allow the calculation of dilution times using optimum
multiparameter techniques. Tritium in conjunction with CFCs
and SF6 will allow the quantification of ventilation ages and
the trasist times since a water parcel was last in contact with
the atmosphere. They will also give a second estimation of
dilution times. Preliminary results for tritium indicate values
~0.15 TU in surface waters, a tritium dead layer at
intermediate depths and an increase in tritium concentration at
depths %4000m. These data provide the basis for modelling
mechanisms that control the dispersal and calculation of the
AABW production rates.
[1] Naveira Garabato, et al. (2002) Deep-Sea Res. II 49, 37353769. [2] Meredith, et al. (2000) J. Geophys. Res. 105, 10931104. [3] Hoppema, et al. (2001) J. Mar. Res. 59, 257-279.
[1] Morgunova & Perchuk (2011) Russian Geology &
Geophysics, in press.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
How biogenic nano-iron oxides can
control the fate of pollutants
G. MORIN1, G. ONA-NGUEMA1, F. JUILLOT1,
F. MAILLOT, Y. WANG1, M. EGAL2, O. BRUNEEL2,
C. CASIOT2, F. ELBAZ-POULICHET2, G. CALAS1
3
AND G.E. BROWN, JR.
Institut de Minéralogie et de Physique des Milieux Condensés
(IMPMC), CNRS, UPMC, Univ Paris 7, 4, Place Jussieu,
75252 Paris Cedex 05, France
([email protected])
2
Hydrosciences UMR 5569, CNRS, Universités Montpellier I
and II, IRD, Place Eugène Bataillon, CC MSE, 34095
Montpellier cedex 5, France ([email protected])
3
Surface & Aqueous Geochemistry Group, Department of
Geological & Environmental Sciences, Stanford
University, Stanford, CA 94305-2115, USA
([email protected])
1
Nanominerals have been the subject of extensive research
for the last decade, especially because of their exceptional
surface properties. These properties indeed confer to these
nanoparticles an important role in pollutant dynamics via
sorption and precipitation reactions, colloidal transport, and
redox surface reactions (e.g. [1]).
In this communication we will present recent advances in
the identification of such processes in impacted natural
systems as contaminated soils and mining environments as
well as in laboratory systems relevant of water treatment
processes. Microscopic and spectroscopic investigations of
these systems emphasize the role of nano – iron oxides [2, 3],
oxyhydroxides [1], hydroxides [4, 5] and hydroxysulfates [6,
7] from abiotic or microbial origin. Particular attention will be
paid to better understanding the respective roles of physicochemical factors and microbial metabolisms in controlling the
kinetics of nano-mineral nucleation and evolution, and the
ability of these solids to scavenge inorganic pollutants,
especially arsenic. Finally, recent evidence for surface redox
reactions involving reactive oxygen species [8] will be
discussed as a promising process for remediation of
contaminated surface waters.
[1] Charlet et al. (2011) CR Geoscience 343, 123–139.
[2] Morin et al. (2009) Langmuir 25, 9119–9128. [3] Wang et
al. (2008) GCA 72, 2573–2586. [4] Ona-Nguema et al. (2009)
GCA 73, 1359–1381. [5] Wang et al. (2010) ES&T 44, 109–
115. [6] Egal et al. (2009) Chemical Geol. 265, 432–441.
[7] Egal et al. (2010) Appl. Geochem. 25, 1949–1957.
[8] Ona-Nguema et al. (2010) ES&T 44, 5416–5422.
Mineralogical Magazine
1503
Removal of fluoride on Mg–Al mixed
oxides prepared at different
temperatures
S. MORIYAMA*, K. SASAKI AND T. HIRAJIMA
Department of Earth Resource Engineering, Kyushu
University, Motooka 744 Fukuoka, Japan
(*correspondence: [email protected])
Hydrotalcite is in layered double hydroxides (LDHs)
structures, the general chemical formula is represented [M1
(II)1-xM2 (III)x (OH2)]An-x/n· mH2O, where M1 (II) = divalent
cation (Mg2+, Zn2+, Ni2+, Co2+, Mn2+, Cd2+), M2 (III) = trivalent
cation (Al3+, Fe3+, Cr3+), An1 = interlayer anion with valence n,
x is M2 (III/M1 (II) + M2 (III). In the present study Mg–Al
mixed oxides, which were obtained by thermal decomposition
of precipitated hydrotalcite-like compounds, were used as
sorbents to remove fluoride in aqueous systems. Calcination
temperatures were 873 K, 1073 K, and 1273 K.
The XRD peaks for co-precipitation products were
assigned to hydrotalcite, but this pattern completely
disappeared and assigned to MgO after calcination at each
temperature, spinel phase was also observed at 1273 K. Higher
calcination temperature provided higher crystallinities and
larger crystal size of mixed oxide which was confirmed by
TEM images. Fluoride sorption on mixed oxides can be
mainly explained by ionic exchange of OH1 to F1. Mg and Al
ions were released during the sorption of fluoride; the
behaviors of released Mg and Al during the sorption of
fluoride have been affected by the elemental distributions of
the surface on mixed oxides. The molar ratio of Al/Mg in
hydrotalcite-like compounds before calcinations was
determined to 0.33 after acid decomposition; however XPS
results indicate that the molarl ratio of Al/Mg on the surface of
mixed oxide increased by the calcination temperatures. After
sorption of fluoride, hydrotalcite have been reconstructed
again with mixed oxide calcined at 873 K and 1073 K,
however, less crystalline hydrotalcite, Mg (OH)2, and spinel
were observed on mixed oxides calcined at 1273 K. The
lowest sorption efficiency of mixed oxide calcined at 1273 K
probably due to the small amount of MgO by the phase
transition to spinel because the spinel was stable in water and
doesn’t react with fluoride. On the other hand, removal of
fluoride was more easily achieved in mixed oxides calcined at
1073 K than another mixed oxides; this may be caused by
good correlation with lattice parameter of MgO. Mg–Al mixed
oxides is one of promising products to remove anion including
fluoride, but the sorption efficiency are affected by properties
of the surface molar ratio and structures, therefore calcination
temperatures must to be considered.
www.minersoc.org
Goldschmidt Conference Abstracts
1504
H2O-CO2 solubility in mafic melts
Y. MORIZET , G. IACONO-MARZIANO * AND
F. GAILLARD2
1
1
2
2
Université de Nantes, UMR 6112, France
ISTO, UMR 6113 CNRS-Université d’Orléans, France
(*correspondence: [email protected])
Water and carbon dioxide are the two most abundant
volatile species in volcanic gases. Accurate laws describing
their solubilities in silicate melts are therefore crucial to
understand volcanic degassing and interpret melt inclusion
entrapment depths. We present here new experimental data on
H2O-CO2 solubility in mafic melts with variable chemical
compositions (alkali basalt, lamproite and kamafugite) that
extend the existing database. We show that potassium and
calcium-rich melts can dissolve ~ 1 wt% CO2 at 3500 bar and
1200°C, whereas conventional models predicts solubilities of
0.2-0.5 wt%, under similar P-T conditions. These new data,
together with those already existing in the literature, stress the
fundamental control of melt chemical composition on CO2
solubility. We present a H2O-CO2 solubility model for mafic
melts, which employs simplified concepts of gas-melt
thermodynamics and accounts for the combined effects of
melt chemical composition and structure. The model is
calibrated on a selected database consisting of 270
experiments with 43 different mafic compositions. The
statistic analyses of the experimental data indicate that the
structure and the chemical composition of the melt play a
fundamental role in CO2 solubility in mafic melts, whereas
H2O solubility is negligibly affected by melt composition and
structure. CO2 solubility mainly depends on the amount of
non-bridging oxygen per oxygen (NBO/O) in the melt, but the
nature of the cation bounded to NBO is also critical. Alkalis
(Na+K) bounded to NBO result in a strong enhancement of
CO2 solubility, whereas Ca has a more moderate effect. Mg
and Fe bounded to NBO have the weakest effect on CO2
solubility. Other structural parameters, such as the agpaitic
index (Al2O3/ [CaO + K2O + Na2O]), are shown significant,
though not as critical as NBO/O. Finally, we modelled the
effect of water on CO2 solubility and suggest that molecular
H2O enhances its solubility, whereas hydroxyls appear to have
the opposite effect. In contrast with CO2, H2O solubility in
mafic melts shows a weak correlation with NBO/O, and is
statistically independent on melt composition.
Mineralogical Magazine
Migration of europium and uranium
in opalinus clay influenced by pH and
temperature
C. MÖSER*, R. KAUTENBURGER AND H.P. BECK
Institute of Inorganic and Analytical Chemistry and
Radiochemistry, Saarland University, Saarbrücken,
Germany
(*correspondence: [email protected])
Introduction
The development of a disposal in deep geological
formations for high-level radioactive waste is a very important
task for the future. The migration of radionuclides through soil
is one of the critical paths from leaked stored container to the
environment [1]. As metals of interest, europium as
homologue of americium and uranium as principal component
of nuclear fuel elements were used.
Spotlight of our investigations is the sorption of europium
and uranium onto Opalinus clay. To get a first understanding
for the different sorption processes we used batch
experiments. During this experiments we varied the conditions
like pH and temperature.
Results
The sorption of the metal ions is strongly pH-dependent.
At pH<7 the Eu sorption decreases strongly. The uranium
sorption decreases strongly between pH 6 and 9. An
explanation afford the formation of the neutral Ca2UO2 (CO3)3
species, which doesn´t sorbed onto the clay [2, 3]. The
necessary carbonate and calcium was dissolved out of the
Opalinus clay. For the investigations synthetic porewater was
used. It has an ionic strength of 0.4 M and the concentration of
cations is more than 7g·L-1. These porewater cations influence
the sorption of europium in a pH range <7 significantly. Due
to the presence of competing cations the sorption of Eu is
inhibited. The uranium sorption is nearly independent from the
competing cations. The influence of pH and temperature is
significant higher. With an increasing temperature from 298 to
333 K the sorption of the metals increases, too. Investigations
at different temperatures allow it to calculate the entropies and
enthalpies for the reactions with uranium and europium
derived from Van´t Hoff plots.
[1] Wang et al. (2011) J. Radioanal. Nucl. Chem. 287, 231–
237. [2] Liu et al. (2005) Environ. Sci. Technol. 39, 4125–
4133. [3] Meleshyn et al. (2009) Environ. Sci. Technol. 43,
4896–4901.
www.minersoc.org
Goldschmidt Conference Abstracts
Monitoring emissions from the
Athabasca Oil Sands using stable
isotopes from black spruce
(Picea mariana)
HEATHER MOSHER* AND ALEXANDER P. WOLFE
University of Alberta, Edmonton T6G 2E3, AB, Canada
(*correspondence: [email protected])
Atmospheric deposition in boreal forest ecosystems
The Athabasca Oil Sands industrial complex in
northeastern Alberta, Canada, emits tons of CO2, NOx and SOx
daily, as well as various trace metals and aromatic
hydrocarbons. The effects of these emissions on the
surrounding, nutrient-limited, boreal forest ecosystem is not
yet fully understood, especially with regards to deposition of
bio-available reactive nitrogen (Nr). The possibility exists that
industrial nitrogen subsidies may increase forest production,
although this has not yet been assessed.
Nitrogen and carbon stable isotope data from year-old
black spruce needles (Picea mariana) collected around the
Athabasca Oil Sands suggest a possible fertilization effect
promoting tree growth. Observed depleted nitrogen values
correspond well with depleted carbon values regionally.
However, the most proximal sites show clear signals that
increased deposition may result in tree physiological stress,
most likely related to the deposition of trace metals, and thus
locally annulling any positive effects of Nr deposition on tree
growth. Paired C and N sotopes from wood cellulose generally
support needle measurements, together providing a detailed
overview of the interactions between atmospheric deposition,
nutrient cycling and tree ecophysiological stress.
1505
Initial results from a new time
resolved microfocus XEOL facility at
the Diamond Light Source
J.F.W. MOSSELMANS1, R.P TAYLOR1,2, A.A. FINCH2
1
AND P.D. QUINN
Diamond Light Source, Didcot, OX11 0DE, UK
(*correspondence [email protected])
2
Dept. of Earth Sciences, St Andrews, KY16 9AL, UK
([email protected])
1
Time Resolved spectrometer
We have constructed a Time-Resolved X-ray Excited
Optical Luminescence (TR-XEOL) detection system at the
Micofocus Spectroscopy beamline I18 at the Diamond Light
Source. TR-XEOL allows the study of short lived states in
isolation from long-lived cascade generated signals and thus
potentially identify and study transient luminescent centres.
The system uses a Horiba-Jobin Triax Spectrometer and
Hamamatsu R3809U-50 microchannel-plate photo multiplier
tube. Triggering on the RF clock, we are able to record data in
time bins of 6.2 ps in the 230 ns gap between the hybrid bunch
photons and those from the main group of electron bunches
orbiting the ring. We can detect light over the range 180-850
nm using a bespoke optical fibre, with X-ray excitation
energies between 2 and 20 keV.
Figure 1: TR_XEOL spectrum from Labradorite Feldspar at
400 nm fitted with 2 exponentials of 1.6 and 29.7 ns.
Initial results
We have examined several different feldspars looking at
the short-lived emissions in the UV region. We have observed
two exponential decay lifetimes at 400 nm one with a lifetime
of 1.6 ns and a second of 29.7 ns from a single crystal
labradorite plagioclase feldspar (RT50c, Smithsonian
Institute), an untreated single crystal collected from Clear lake
Utah USA. In contrast, R1-11a, a microcline cryptoperthite
from the Prins Christians Sund granite suite South Greenland
[1], showed variable lifetimes at 400 nm, a short lifetime
whose mean value was 0.20±0.13 ns and a longer life
component of 13.5 ns. The potential of TR-optically detected
XAS will be discussed.
Mineralogical Magazine
[1] Finch & Klein (1999) Contr. Mineral. Petrol. 135, 234–
243.
www.minersoc.org
1506
Goldschmidt Conference Abstracts
Serpentine and brucite intergrowths:
effects on " 11B
Direct molecular simulation of
aqueous electrolyte solubility
F.E. MOTHERSOLE1*, K.A. EVANS1 AND J. CLIFF2
F. MOUCKA1,2 AND W.R. SMITH1*
Curtin University of Technology, Bentley, WA 6845,
Australia
(*correspondence: [email protected])
2
Centre for Microscopy, Characterisation and Analysis,
University of Western Australia, Australia
Un. of Ontario Institute of Technology, Oshawa, ON Canada
L1H 7K4 (*correspondence: [email protected])
2
J. E. Purkinje University, 40096 Usti n. Labem, Czech
Republic
A quantitative understanding of fluid:rock interaction is
important for understanding the transfer of elements and fluid
circulation within the crust. Serpentinites can provide a
sensitive record of fluid-rock interaction, particularly via
analysis of isotopes of fluid mobile elements, such as boron.
Previous studies of boron in serpentinised rocks have
provided a wide range of values. 11B partitions into seawater,
so heavy "11B values indicate a sewater influence, while
lighter "11B reflects mantle influences. Strong fractionation
between the two isotopes at temperatures of serpentinisation
enables elucidation of the evolving fluid:rock system with
progressive serpentinisation.
However, boron isotopic fractionation is influenced by
temperature and pH because 11B is preferentially incorporated
into trigonal environments, such as those found in the B (OH)3
aqueous species, while 10B is preferentially hosted by the B
(OH)4- tetragonal species, which dominates in solution at high
pH [1]. Additionally serpentine minerals, particularly early
grown serpentine, can be intimately intergrown with brucite.
Brucite cations are held in a trigonal site, so the presence of
brucite is expected to increase "11B. If this is not recognised,
"11B values heavier than the true serpentine "11B values will
be inferred, and erroneous interpretations may be made.
In this study, brucite, serpentine and brucite-serpentine
intergrowths of partially serpentinised peridotites from ODP
Leg 209 and New Caledonia were identified using microraman spectroscopy. Secondary Ion Mass Spectrometry
(SIMS) was used to assess the extent to which the presence of
brucite affects "11B. The results enable a quantitative
assessment of the magnitude of the effect of brucite on "11B
and the implications of this for interpretation of fluid:rock
interaction during serpentinisation.
We describe a new and computationally efficient
methodology using Osmotic Ensemble Monte Carlo (OEMC)
simulation to calculate the solubility of aqueous electrolytes
[1]. We apply it to directly determine solubility without the
need for calculating chemical potentials. The method avoids
calculations for the solid phase, directly incorporating readily
available data from thermochemical tables based on welldefined reference states [2].
1
1
Introduction
Methodology
The method performs simulations of the aqueous solution
at a fixed number of water molecules, pressure, temperature
and specified overall electrolyte chemical potential.
Insertion/deletion of ions to/from the system is implemented
using fractional ion states, and transitions between the states
incorporates Wang-Landau sampling.
Results and Discussion
We have applied the approach to calculate the solubilities
of a range of alkali halides, using several water and ionic
force-field models from the literature. We consider both
individual alkali halides and their mixtures, dissolved in both
H2O and HCl-H2O solutions. The solubility predictions are
generally good. The solubility is very sensitive to the force
field employed.
[1] F. Moucka, M. Lisal, J.Skvor, J. Jirsak, I. Nezbeda & W.R.
Smith (2011) J. Phys. Chem. B, submitted.[2] M. Chase, Jr.
(1998) NIST-JANAF Thermochemical Tables, J. Phys. &
Chem. Reference Data Monograph No. 9, Am. Chem. Society,
Am. Inst. Physics.
[1] Foustoukos et al. (2008) Geochimica et Cosmochimica
Acta 72(22) 5457–5474.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
An unusual Hf-Pb signature below
the East Pacific Rise – Mathematician
Hotspot system
Interperetaion of microtexture and
microstructure in the dynamic
metamorphic rocks in Mouteh Mine
area, Iran
BÉRENGÈRE MOUGEL, ARNAUD AGRANIER,
CHRISTOPHE HÉMOND AND PASCAL GENTE
UMR 6538 Domaines Océaniques, IUEM, Université de
Brestagne Occidentale, 26980 Plouzané, France
The Northern part of the East Pacific Rise (EPR), between
the Riviera and Orozco Fracture zones shows an atypical
morphology. It is 300m shallower than the rest of the ridge
and is unusually wide. On its western side, a strong alignment
of seamounts intersects perpendicularly the ridge in its most
inflated part, suggesting a hotspot-ridge interaction.
This study reports new Hf and Pb isotopes and trace
element concentrations for 57 MORB samples, collected by
submersible ‘Nautile’ during cruise PARISUB (2010). It
covers a 15 km transect along the ridge axis from 15°37'N to
15°47°N with an average sampling of space ~300m.
REE patterns shows typical intermediate E-MORB
compositions with relatively flat LREE profiles and significant
depletions in HREE.
206
Pb/204Pb range from 17.5 to 18.2; 208Pb/204Pb=36.8-37.6;
207
204
Pb/ Pb= 15.46-15.51; !Hf= 8.7-11.5. All the Pb ratios over
204
Pb are correlated with each other, as well as with
176
Hf/177Hf. These clean correlations most likely reflect binary
mixings occurring in the mantle source between the local
DMM and enriched material (EM). 206Pb/204Pb and 208Pb/204Pb
ratios are also unusually low even for MORB. They are
actually the lowest values ever reported for the EPR, which is
unexpected for a plume-ridge interaction. Moreover,
alignments in 207Pb/204Pb vs 206Pb/204Pb or 208Pb/204Pb diagrams
are distinct from any geochemical trend known for this ridge
(207Pb/204Pb, too high for given 206Pb/204Pb and 208Pb/204Pb).
The positive correlation between Hf and Pb isotopes is
even more remarkable, that geochemical enrichments typically
lead to radiogenic Pb and un-radiogenic Hf signatures and,
therefore, that DMM-EM mixtures usually appear as negative
correlations in the Hf-Pb isotope spaces.
The least radiogenic Hf and Pb correspond to the samples
the closest to the Seamounts-ridge intersection (15°43'N)
suggesting that these unusual compositions reflect the
Mathematician EM material.
Mineralogical Magazine
1507
SEYED ZAHED MOUSAVI1* AND KHATEREH PANAHI2
1
Basic Science Department, Islamic Azad University(I.A.U),
Meshkinshahr Branch,Meshkinshahr, Iran
(*correspondence: [email protected])
([email protected])
Introduction
The studied area is located in the central part of SanadajSirjan belt, 60 km south part of Delijan city, the Muteh mine
area. The formations at this area are Devonian silicic volcanic
and volcano clastic rocks that have been metmorphed at green
schist –amphiboloit facies.This rocks have altered by some
Basic intrusive.
Methods and Results
Above 60 thin section have taken from drilling core
samples. The aim of this studding is a interpretation of micro
texture & microstructure by microscope. The result of
studding show some micro texture like CS, C/ fabric, Mineral
Fish, Bookshelf Structure, Boudinage, Strain Shadow, !, &, N
pyroclast. In addition we can find three metamorphism setting
(D1, D2, D3) at this area. Every one this micro texture &
microstructure have made in various metamorphism and
deformation setting.
[1] Cees W. Passchier & Rudolph A.J. Trouw (2005)
Microtectonics 2th edition.springer, 140–143, 152–153.
[2] David A.Ferrill, Alan P Morris, Mark A. Evance, Martin
Burkhard, Richard H. Groshong Jr. (2004) Journal of
Structural Geology 26, 1521-1529.
www.minersoc.org
1508
Goldschmidt Conference Abstracts
Sulfur and strontium isotope study of
hydrothermal mineralization from
the SE Afar Rift
N. MOUSSA1,2,3*, O. ROUXEL1,2, P. NONNOTTE2,
Y. FOUQUET1, E. PONZEVERA1 AND J. ETOUBLEAU1
IFREMER, Centre de Brest, BP 70- 29280 Plouzané, France
UMR 6538 Domaines Océaniques, UBO-IUEM, Place
Copernic, 29280, Plouzané, France
3
IST, Centre d’Etude et de Recherche de Djibouti, BP 486,
Djibouti
(*correspondence: [email protected])
1
2
Epithermal mineralization was recently described in the
SE Afar Rift (Republic of Djibouti). To infer fluid sources in
hydrothermal veins, sulfur and strontium isotopic analyses
were performed on thirty mineralized samples of chalcedony,
and/or quartz, ± carbonate containing gold and sulfides.
Gypsum occurs as individual mounds and shallow stockwork
zones. Isotopic composition of sulfides and sulfates were
determined using Multicollector-Inductively Coupled Plasma
Mass Spectrometer (MC ICPMS) and Thermal Ionisation
Mass Spectrometer (TIMS) methods [1]. Sulfur isotopic
composition of sulfides (mainly pyrite) vary from –0.2 to
+6.8‰. These values are classically reported for volcanic
rocks and hydrothermal sources. Strontium isotopic ratios
(87Sr/86Sr) of mineralized veins range from 0.70391 to
0.70799. The lowest values of 87Sr/86Sr ratios indicate volcanic
source of fluid while the highest isotopic composition indicate
significant seawater contribution (defined at 0.70903, [2]).
Coupled sulfur and strontium isotope compositions of eight
sulfate samples hosted in (i) gypsum mound; (ii) evaporites
(iii) stockwork veins in sediment or in volcanic rocks were
also investigated to characterize the sources of Sr and S. The
&34S values of the sulfate range from –1 to +14.3‰ while the
87
Sr/86Sr compositions fall in the range 0.70389-0.70639. The
highest values of 87Sr/86Sr ratios (0.70639) in gypsum
correspond to the lighter values of &34S (+14.3‰.). These
relatively light &34S values can be explained by the
disproportionation of magmatic SO2. This implies that both
acidic fluid of magmatic origin and saline fluids contribute to
the hydrothermal system in the Afar Rift.
[1] Craddock et al. (2008) Chem. Geol 253, 102–113.
[2] Barrat et al. (1993) GCA 57, 2291–2302.
Isotopic fractionation of zinc in
planetary basalts
F. MOYNIER1, R. PANIELLO1 AND J.M.D. DAY2
Dept. Earth Planet. Sci, Washington Univ. St Louis, MO
63130 ([email protected], [email protected])
2
Geosci. Res. Div., Scripps Institution of Oceanography, La
Jolla, CA 92093-0244 ([email protected])
1
Zinc is a moderately volatile chalcophile trace element and
so preserves evidence for volatility-driven processes during
planetary accretion. For this reason, Zn can be used to
understand the origin and evolution of planetary bodies,
including Earth-Moon system formation. Terrestrial igneous
rocks exhibit a limited range in zinc isotopic composition
(&66Zn = +0.3±0.1‰, 2SE), whereas large variations have
been found in lunar soils (&66Zn up to +6.4‰ [1]) and tektites
(up to +2.04‰ [2]) associated with volatilization processes.
Here we report new Zn isotopic data for low- and high-Ti
mare basalts to directly address the origin of the Earth and
Moon. We also present new Zn isotopic data for martian
meteorites, which have identical Zn isotopic compositions,
within uncertainties (&66Zn = +0.25±0.03‰, 2SE, n=10), to
terrestrial lavas. Absolute Zn concentrations in mare basalts
(0.6-12ppm) are generally significantly lower than for
terrestrial lavas (typically >75ppm), silicate Earth estimates
(~55ppm), CI chondrites (>300ppm), or lunar pyroclastic
beads (>90ppm) [1]. With the exception of two outliers, lowTi and the high-Ti lunar basalts have similar mean &66Zn
values of +1.31±0.13‰ (n=11) and +1.39±0.31‰ (n=8),
respectively, and similar ranges (+0.8 to +1.6‰ and +0.5 to
+1.9‰, respectively). By comparison, lunar regolith materials
have higher &66Zn values due to micrometeorite impacts
and/or cosmic ray sputtering, and lunar pyroclastic beads are
enriched in light isotopes (-3.7±0.3‰ [1,3]).
Zinc isotopic homogeneity in terrestrial and martian
igneous rocks and lack of obvious isotopic fractionation of Zn
in low- and high-Ti mare basalts (versus O or Fe [4]) suggest
that igneous processes do not fractionated Zn isotopes
significantly. Values of &66Zn were probably not inherited
from the proto-Earth (for Earth) or Theia (for the Moon)
because chondrite meteorites have lower &66Zn (<0.8‰) than
mare basalts [5]. Instead, enrichments in heavy Zn isotopes for
mare basalts are likely a consequence of degassing either
following giant impact, or during basaltic eruption.
Alternatively, Zn isotopic fractionation during giant impact,
followed by stochastic late accretion [6,7] led to the Zn
isotopic compositions seen in terrestrial, martian and lunar
igneous rocks.
[1] Herzog (2009) GCA 73, 5884. [2] Moynier (2009) EPSL
277, 482. [3] Moynier (2006) GCA 70, 6103. [4] Liu (2010)
GCA 74, 6249, [5] Luck (2005) GCA 69, 535. [6] Bottke
(2010) Science 330, 1527. [7] Albarede (2009) Nature 461,
1227.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Sediment response to persistently low
oxygen levels in bottom waters:
The Lower St. Lawrence Estuary
A. MUCCI, 1* S. LEFORT1 AND B. SUNDBY1,2
Dept. of Earth and Planetary Sciences, McGill University,
Montreal, Quebec Canada H3A 2A7
(*correspondence: [email protected])
2
Institut des sciences de la mer de Rimouski, Rimouski,
Quebec, Canada
1
Reports of hypoxia (O2 concentrations < 62.5 @mol L11) in
the bottom waters of the coastal ocean, and the extent of the
areas that are affected by hypoxia, have increased at an
alarming rate. Most studies of hypoxic environments focused
on the impacts on pelagic and benthic populations, but the
impact of hypoxia on sediment chemistry is poorly
documented. We compared the chemical composition of
sediment and porewater in cores recovered between 1982 and
2007 at two sites in the Lower St. Lawrence Estuary (LSLE),
where the bottom water has been persistently hypoxic for
more than 25 years. The concentrations and the vertical
distributions of total Fe and As in the cores have not changed
since the 1980s, but the speciation of solid phase Fe and As
have changed significantly. The proportions of reactive Fe and
As components have increased while the degree of pyritization
of Fe and As has decreased by 50% and 75%, respectively. In
addition, the concentrations of porewater Fe and As have
increased since 1982. We propose that in marine, iron-rich
environments, such as the LSLE, the hypoxia interferes with
pyritization, which normally would immobilize elements such
as As by incorporating them into stable authigenic pyrite
phases.
1509
Fate of As upon microbial
Fe(III) reduction of
As-bearing biogenic Fe minerals
E.M. MUEHE*, L. SCHEER AND A. KAPPLER
Geomicrobiology, University of Tuebingen
(*correspondence: [email protected])
In arsenic-contaminated groundwater and soil, aqueous
arsenic enters the human food chain directly via drinking
water or indirectly via plants and animals, potentially leading
to devastating health effects on people. Hence, research has
focused on the geochemical and biogeochemical processes
leading to the mobilization (release) and immobilization
(removal) of arsenic from aquifers and soil. Former studies by
Hohmann et al. [1] demonstrated that Fe(II)-oxidizing bacteria
can efficiently immobilize arsenic by forming biogenic Fe(III)
hydroxides. In the presence of arsenic these microorganisms
form co-precipitates of Fe(III) (hydr)oxides and arsenic and
additionally arsenic is sorbed to the mineral surfaces.
However, the co-existence of Fe(II)-oxidizing with
Fe(III)-reducing bacteria in the environment could result in Fe
cycling by the reduction of biogenic Fe(III) (hydr)oxides. This
could lead either to a dissolution of the Fe(III) minerals
causing a release of the bound arsenic or alternatively to the
formation of secondary Fe(II/III) mineral phases [2] and an
immobilization of arsenic.
In this study, we followed the reduction of biogenic
arsenic-bearing Fe(III) minerals by the Fe(III)-reducer
Shewanella oneidensis MR-1. We then compared the As
(im-)mobilization during the reduction of these biogenic
Fe(III) hydroxides to the As (im-)mobilization from
chemically-synthesized Fe(III) minerals including the poorlycrystalline mineral ferrihydrite and the highly crystalline
mineral goethite.
The resulting iron minerals were identified and
characterized by X-ray diffraction, Mössbauer spectroscopy
and electron microscopy. First results show that arsenic is only
partially remobilized during microbial reduction of biogenic
Fe-As-co-precipitates and that the remaining arsenic is bound
either to the non-reduced goethite or to the newly formed Fe
(II) carbonate and phosphate mineral phases.
[1] Hohmann et al. (2010) ES&T 44, 94-101. [2] Tufano and
Fendorf (2008) ES&T 42, 4777-4783.
Mineralogical Magazine
www.minersoc.org
1510
Goldschmidt Conference Abstracts
Measuring the elastic properties
under simulated Earth’s mantle
conditions
Using Ambient Pressure X-ray
Photoelectron Spectroscopy to
investigate the reduction of c(2x2)O/Ni(100) by hydrogen
H.J. MUELLER1*, J. LAUTERJUNG1, F.R. SCHILLING2,
C. LATHE1 AND M. WEHBER2
GFZ German Research Centre for Geosciences,
Telegraphenbergm D-14473, Potsdam, Germany
(*correspondence: [email protected])
2
KIT Karlsruher Institute of Technology – Universität
Karlsruhe, Engler-Bunte-Ring 14, D-76131, Karlsruhe,
Germany ([email protected])
KATHRIN MÜLLER1, ANDERY SHAVORSKIY2,
HENDRIK BLUHM2 AND DAVID STARR1*
1
The Earth’s mantle is only accessible by indirect methods,
above all seismological studies. The interpretation of seismic
data from the Earth’s deep interior requires measurements of
the physical properties of Earth materials under experimental
simulated mantle conditions. In principle there are 2 common
ways of simulating these in situ conditions by high pressure
techniques - diamond anvil cells (DAC), large volume presses
(LVP). The latters are more limited in pressure, but provide
sample volumes 3 to 7 orders of magnitude bigger. They also
offer small and even adjustable temperature gradients over the
whole sample. Ultrasonic interferometry allows the highly
precise travel time measurement at a sample enclosed in a
LVP under in situ conditions. The data transfer function
technique (DTF) even makes transient measurements possible.
From geophysical point of view the up to 6 orders of
magnitude lower frequency range as used for optical
techniques in DAC and the option of using complex samples,
i.e. polycrystalline, polyphase mineral assemblages, make the
results much more representative for comparison with field
data. Simultaneous structural and deformation measurements
require the installation at a 3rd generation synchrotron light
source. We present recent techniques and results of elastic
properties measurements performed at different large volume
presses.
Center for Functional Nanomaterials, Brookhaven National
Laboratory, Upton, NY 11973, USA
(*correspondence: [email protected])
2
Chemical Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, CA 94720, USA
1
X-ray Photoelectron Spectroscopy (XPS) is a powerful
tool for the chemical analysis of surfaces. Typically XPS
measurments are performed under ultra-high vacuum
conditions, which are far removed from many environmental
or technologically relevant conditions. The development of
synchrotron based Ambient Pressure XPS (AP-XPS) that
incorporates a differentially pumped electrostatic lens system
into the electron energy analyzer has made possible XPS
measurments at pressure up to about 5 Torr. In this
presentation, after a brief introduction to the AP-XPS
technique, results using AP-XPS to investigate the reduction
of a chemisorbed oxygen layer on Ni (100) by hydrogen will
be discussed.
Among transition metal oxides, NiO has been the focus of
extensive fundamental studies due to its applications in
catalysis and potential magnetic devices. The reduction of NiO
has been studied at elevated pressure conditions using a broad
range of techniques including X-ray Diffraction [1], and Near
Edge X-ray Absorbtion Spectroscopy [2] among others.
Relatively unexplored is the reduction of chemisorbed oxygen
on the surfaces of Ni single crystals at elevated pressures.
We have investigated the reduction of the c (2x2)-O
chemisorbed layer on Ni (100) using AP-XPS at temperatures
from 100 °C to 150 °C and pressures up to 0.5 Torr. The
presence of small NiO clusters, located at step edges as shown
by scanning tunneling microscopy, have a significant impact
on the reduction kinetics of the c (2x2)-O layer. These clusters
are preferntially reduced compared to the c (2x2)-O layer and
increase the reduction rate of the c (2x2)-O layer, quite likely
from spill-over of dissociated hydrogen from the NiO islands.
[1] J. A. Rodriguez, J. C. Hanson, A. I. Frenkel, J. Y. Kim, M.
Perez (2002) JACS 124, 346–354. [2] J. G. Chen, D. A.
Fischer, J. H. Hardenbergh, R. B. Hall (1992) Surf. Sci. 279,
13–22.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Monazite dating of base-metal
mineralization, Earaheedy Basin,
Western Australia
Volatiles in the mantle: Impact on
intraplate magmatism
SAMUEL B. MUKASA1*, CHRIS STEFANO2,
MARIA MARCANO2, THOMAS HUDGINS2,
MARY PETERSON3 AND NOBU SHIMIZU4
J.R. MUHLING1*, I.R. FLETCHER2 AND B. RASMUSSEN2
CMCA, Univ. Western Australia, Crawley, 6009, Australia
(*correspondence: [email protected])
2
Dept Applied Geology, Curtin Univ., Bentley, 6102,
Australia ([email protected],
[email protected])
1
The Paleoproterozoic Earaheedy Basin occupies the
eastern end of the Capricorn Orogen that separates the
Archean Pilbara and Yilgarn Cratons. The maximum
depositional age of the Yelma Formation at the base of the
Earaheedy Group is less than ~2.0 Ga from detrital zircon
dating [1], while the minimum age is very poorly constrained.
Sandstones of the Yelma Formation overlie granitic rocks of
the Yilgarn Craton in the Earaheedy Basin, and outliers that
extend up to 100 km south of the basin overlie Yilgarn Craton
rocks or metasedimentary rocks of the Yerrida Group. The
Yelma Formation was deposited on a broad shallow shelf over
an extensive area of the northern margin of the Yilgarn
Craton. Within the basin, carbonates of the Sweetwaters Well
Member of the Yelma Formation host minor Pb-Zn sulphide
mineralization of Mississippi Valley type [2]. Secondary Pb
mineralization, interpreted to have resulted from weathering
and remobilization of sulphide mineralization [3, 4], is being
mined in ouliers of Yelma Formation at Magellan and Cano.
207
Pb/206Pb dating of authigenic monazite in sandstones of
the Yelma Formation within the Earaheedy Basin gave an age
of 1.81 Ga, which is interpreted to be the age of metamorphic
or hydrothermal fluid flow, and may be related to the MVT
mineralization. This age provides a firm minimum for
deposition of the formation. At Cano, monazite is intergrown
with iron oxides, interpreted to have replaced pyrite, in Pbbearing greywacke. 207Pb/206Pb dating gave a similar, though
imprecise, age, with many analyses recording high levels of
common Pb. A Pb/Pb isochron age derived from outgrowths
of xenotime on detrital zircon gave the same age, within error,
and Pb isotope compositions support consanguinity with the
MVT mineralization.
REE phosphates are very sensitive to the passage of
metamorphic and hydrothermal fluids, often recording
multiple fluid events. In the Earaheedy Basin, they constrain
the depositional age of the Yelma Formation to ~2.0-1.81 Ga,
and the timing of base metal mineralization to ~1.81 Ga.
Department of Earth Sciences, University of New Hampshire,
Durham, NH 03824
(*correspondence: [email protected])
2
Department of Geological Sciences, University of Michigan,
Ann Arbor, MI 48109
3
Department of Geological Sciences, Brown University,
Providence, RI 02912
4
Woods Hole Oceanographic InstitutionO, OWoods Hole, MA
02543
1
Concentrations of the volatiles H2O, CO2, S, Cl, and F and
elemental compositions of primary magmas and their sources
can be estimated through the study of olivine-hosted melt
inclusions in volcanic rocks, thereby providing insights about
melting processes in the mantle. These volatiles play a major
role in both the formation and evolution of mantle melts, and
yet their impact on intraplate volcanism on the continents and
in the ocean basins may be grossly underestimated. We have
determined the major-oxide, trace-element and volatile (H2O,
CO2, S, Cl, and F) concentrations of olivine-hosted melt
inclusions from the Columbia River Plateau (CRP)-Snake
River Plain (SRP) large igneous province, West Antarctic Rift
System, and Iceland, all three areas with intraplate volcanism
hypothesized to be related to plume activity.
Most of the samples we have analyzed record minimum
H2O concentrations of 1 wt% or higher, exceeding the largest
values obtained for subaerial eruptions in Hawaii of 0.8 wt%.
The most H2O-rich lava in the SRP has 3.3 wt%, and in the
Columbia River Basalts (CRB) values reach 4.2 wt% H2O.
Concentrations in Icelandic and West Antarctic Rift melt
inclusions reach values of 3.0 and 2.2 wt% H2O, respectively.
Water and CO2 are correlated and follow magmatic degassing
curves. Furthermore, the highest volatile concentrations are
always found in the more primitive melt inclusions, based on
major oxide and trace element abundances, indicating that the
volatiles are of mantle origin, not artefacts of differentiation in
the crust. The trace element and volatile variability, high
concentrations of water, and recent studies of Os isotopes in
these tectonic settings provide compelling evidence that the
volatiles and chemical heterogeneity of the magma sources
may be caused by the recycling of ancient oceanic crust.
[1] Halilovic et al. (2004) Precambr. Res. 128, 343–366.
[2] Teen (1996) BSc (Hons) thesis, U. Tas, 128 pp.
[3] McQuitty & Pascoe (1998) Aust. Inst. Min. Metall. Mon.
22, 293–296. [4] Pirajno (2004) Precambr. Res. 128, 411–439.
Mineralogical Magazine
1511
www.minersoc.org
Goldschmidt Conference Abstracts
1512
I-Pu-Xe in OIBs and the early
separation of the plume source from
the MORB source mantle
SUJOY MUKHOPADHYAY
Dept. of Earth and Planetary Sciences, Harvard University,
Cambridge, MA 02138, USA ([email protected])
The noble gases provide unique insights into mantle
structure and the origin of the different mantle reservoirs. In
particular, the noble gases are thought to provide one of the
strongest evidence for regions of the deep mantle to have
largely escaped melt extraction. However, the interpretation of
the noble gas data remains a matter of active debate. For
example, OIBs have lower 40Ar/36Ar and 129Xe/130Xe ratios
than MORBs. This observation has been variously interpreted
to reflect the sampling of a relatively undegassed mantle
reservoir or preferential sampling of recycled plates with
seawater derived atmospheric Ar and Xe. These two
interpretations have very different implications for mantle
differentiation, and the creation and destruction of mantle
heterogeneities. Here I will present new He, Ne, Ar, and Xe
data from Iceland that will allow the above interpretations to
be critically evaluated.
The relative abundances of 4He, 21Ne, and Ar in the
Iceland sample are in the same proportion as the mantle
production rates for these isotopes. As a result, the sample
preserves an elementally unfractionated pattern that allows the
abundance pattern of the priomordial noble gases in the plume
source to be reconstructed. Strong linear relationships are
observed between isotope ratios and elemental ratios (e.g.
40
Ar/36Ar-3He/36Ar, 129Xe/130Xe-3He/130Xe) that reflect mixing
between mantle-derived noble gases and shallow-level
atmospheric contamination. Importantly, while the gas-rich
‘popping rock’ from the N. Atlantic ridge and the Iceland
sample share a common shallow-level atmospheric
contaminant, they trend towards very different mantle
40
Ar/36Ar and 129Xe/130Xe ratios. Additionally, the Iceland
sample has a large proportion of Pu-derived to U-derived
fission xenon. Hence, for the first time, the Iceland data
provides unequivocal evidence that the differences in Ar and
Xe isotopic compositions between MORBs and OIBs cannot
be generated solely through preferential re-circulation of
atmospheric noble gases into the OIB source. The differences
reflect a lower degree of outgassing of the plume source.
Further, because 129Xe is produced from extinct 129I, the result
demonstrates that chemical differences between OIBs and
MORBs must have been established within the first 100 Myrs
of Earth history and subsequent mantle convection has not
wiped out the differences established in the early Earth.
Mineralogical Magazine
Architecture of submicron organomineral domains in soil aggregates –
Evaluation by NanoSIMS
C.W. MÜLLER, C. HÖSCHEN AND I. KÖGEL-KNABNER
Lehrstuhl für Bodenkunde, Technische Universität München,
85350 Freising-Weihenstephan, Germany
(*correspondence: [email protected])
During soil aggregation primary soil particles such as clay
and silt, iron and aluminium (hydro)oxides and particulate
organic matter are bound together to complex aggregates. The
spatial mixture of mineral and organic components results in
diverse interfaces controlling soil organic matter stabilization
but also sorption processes. Until nowadays it was hard to
analyse the spatial distribution of mineral and organic domains
within intact soil aggregates together with its turnover.
The nano-scale secondary ion mass spectrometry
(NanoSIMS) enables us to analyse biogeochemical processes
and properties of inner aggregate spheres at a submicron scale.
NanoSIMS allows the simultaneous analysis of up to seven
ion species with high sensitivity and lateral resolution. With
Cs+ as primary ions, negatively charged ions, like e.g. 12C-,
13 - 12 14 - 12 15 - 27
C , C N , C N , Al16O- and 28Si-, are collected with a
lateral resolution down to 50 nm. Using O- as primary ion,
positively charged ions like e.g. 24Mg+, 40Ca+ and 56Fe+, are
collected with a lateral resolution down to 150 nm.
For the present study we used soil material of topsoils
from an agricultural cropland and a forest. Both soils were
derived from labelling experiments using litter enriched in 15N
(mustard litter on cropland soil, beech litter on forest soil).
The air dried soil aggregates were embedded in an epoxyresin, cut and polished in order to obtain a smooth inner
aggregate surface. A cascade from reflectance light
microscopy, scanning electron microscopy to NanoSIMS was
used to evaluate architecture, elemental composition and 15N
location within intact soil aggregates.
A spatial mixing of mineral compounds into plant residues
with still visible cell structures was shown within aggregates.
We can demonstrate that the incorporated 15N-labelled organic
matter is not distributed homogeneously, but resides at
specific micron-scale spots within soil aggregates. The
packing of mineral and organic domains in soil aggregates
showed distinctively alternating spatial patterns. The
NanoSIMS technique therefore allows the combined in situ
evaluation of specific aggregate structures and their possible
functions in terms of organic matter sorption and turnover.
www.minersoc.org
Goldschmidt Conference Abstracts
Comparative study of the U(VI)
complexation onto $-Al2O3 by ATR
FT-IR and EXAFS spectroscopy
KATHARINA MÜLLER*, HARALD FOERSTENDORF,
ANDRÉ ROSSBERG, KAROLINE STOLZE
AND KATHARINA GÜCKEL
Helmholtz-Zentrum Dresden-Rossendorf, Institute of
Radiochemistry, Dresden, Germany
(*correspondence: [email protected])
Aluminates, representing an essential component of clay
minerals, play a decisive role in regulating the mobility of
contaminants in rock and soil formations, in particular due to
their tendency to form coatings on mineral surfaces [1].
In this work, U(VI) sorption on ,-Al2O3 is comparatively
investigated using in situ vibrational and X-ray absorption
spectroscopy. The focus was set to micromolar U(VI)
concentrations and a variety of environmentally relevant
sorption parameters in order to resolve discrepancies reported
earlier [2-4].
Figure 1: TR ATR FT-IR spectra of U(VI) soprtion on
,-Al2O3.
Time-resolved (TR)IR spectroscopic sorption experiments
at the alumina-water interface evidence the formation of three
different species as a function of surface loading (c. f. Figure
1): a monomeric carbonate complex, an oligomeric surface
complex and a surface precipitate. These results are confirmed
by IR experiments performed at different flow rates, pH
values, ionic strengths, U(VI) concentrations, and in inert gas
atmosphere. Results of EXAFS experiments of batch samples
are consistent to these findings.
[1] Guillaumont, R. (1994) Radiochimica Acta 66–7, 231–242.
[2] Catalano, J. G. et al. (2005) Geochim. Cosmochim. Acta
69, 3555–3572. [3] Moskaleva, L.V. et al. (2006) Langmuir
22, 2141–2145. [4] Sylwester, E. R. et al. (2000) Geochim.
Cosmochim. Acta 64, 2431–2438.
Mineralogical Magazine
1513
The role of comets as possible
contributors of water and prebiotic
organics to terrestrial planets
M.J. MUMMA* AND S.B. CHARNLEY
NASA-Goddard Space Flight Center, Solar System
Exploration Division, Greenbelt, MD, 20771, USA
(*correspondence: [email protected])
The question of exogenous delivery of organics and water
to Earth and other young planets is of critical importance for
understanding the origin of Earth’s water, and for assessing
the prospects for existence of Earth-like exo-planets. Viewed
from a cosmic perspective, Earth is a dry planet yet its oceans
are enriched in deuterium by a large factor relative to nebular
hydrogen. Can comets have delivered Earth’s water? The
deuterium content of comets is key to assessing their role as
contributors of water to Earth.
Icy bodies today reside in two distinct reservoirs, the Oort
Cloud and the Kuiper Disk (divided into the classical disk, the
scattered disk, and the detached or extended disk populations).
Orbital parameters can indicate the cosmic storage reservoir
for a given comet. Knowledge of the diversity of comets
within a reservoir assists in assessing their possible
contribution to early Earth, but requires quantitative
knowledge of their components – dust and ice. Strong
gradients in temperature and chemistry in the proto-planetary
disk, coupled with dynamical dispersion of an outer disk of icy
planetesimals, imply that comets from KD and OC reservoirs
should have diverse composition.
The primary volatiles (native to the nucleus) provide the
preferred metric for building a taxonomy for comets, and the
number of comets so quantified is growing rapidly.
Taxonomies based on native species (primary volatiles) are
now beginning to emerge [1, 2, 3]. The measurement of
cosmic parameters such as the nuclear spin temperatures for
H2O, NH3, and CH4, and of enrichment factors for
isotopologues (D/H in water and hydrogen cyanide, 14N/15N in
CN and hydrogen cyanide) provide additional tests of the
origin of cometary material. I will provide an overview of
these aspects, and implications for the origin of Earth’s water
and prebiotic organics
[1] Mumma & Charnley (2011) Ann. Rev. Astron. Astrophys.
in press. [2] DiSanti & Mumma (2008) Sp. Sci. Rev. 138, 127.
[3] Crovisier et al. (2009) Earth, Moon, Planets 105, 267.
www.minersoc.org
1514
Goldschmidt Conference Abstracts
Change in lead sorption during
transformation of monohydrocalcite
to aragonite
T. MUNEMOTO AND T. MURAKAMI
Department of Earth and Planetary Science, the University of
Tokyo, Tokyo 113-0033, Japan
(*correspondence: [email protected])
Monohydrocalcite (CaCO3·H2O) (MHC) is a metastable
calcium carbonate found in the sediments of mordern saline
and alkaline lakes. MHC transforms to anhydrous calcium
carbonates such as calcite and aragonite [1]. The sorption
behavior of aqueous metal ions to calcite, the most stable
calcium carbonate, is well known [2], but little to metastable
calcium carbonates. We conducted uptake experiments of lead
ion on monohydrocalcite to examine change in sorption
behavior of lead ion during transformation of
monohydrocalcite to aragonite.
Solutions of Na2CO3, NaHCO3, NaNO3, NaOH, HNO3,
and 1µM of Pb2+ (I = 0.13) were adjusted to pH 8.50, 9.00,
and 9.50 by changing the concentrations; the concentration of
CO32- was kept constant for any solutions. Then, 2g/L of
synthesized monohydrocalcite was added to the solutions at 25
°C, and the concentrations of lead and some other cations were
measured at the end of each batch experiment. The run
duration was up to 15 hours.
Aragonite increased in amount gradually with time while
monohydrocalcite decreased with time; the growth rates of
aragonite were almost the same between the three different pH
conditions. Monohydrocalcite was almost completely replaced
by aragonite for 15 hours. The distribution coefficient,
kd=(Pb)sold/(Pb)solution (L/g), generally decreased with time; the
difference in pH did not show a significant difference in kd.
The kd values were almost the same between the three
different pH conditions after the 15 hour experiments. And the
final uptake of Pb2+ was nearly 90% for all the three differentpH experiments. The kd values during the transformation were
higher than those of calcite and aragonite [2]. Our results
suggest that the kd value decreases with increase in aragonite,
i.e. during the transformation of monohydrocalcite to
aragonite.
[1] Munemoto & Fukushi (2008) JMPS 103, 345–349.
[2] Rouff, et al. (2005) J. Colloid Interface Sci. 286, 61–67.
Indistinguishable Hf/W in the silicate
Earth and the silicate Moon
CARSTEN MÜNKER1,2, STEPHAN KÖNIG1,2
1,2,3
AND TONI SCHULZ
Institut für Geologie und Mineralogie, Universität zu Köln
Steinmann Institut, Universität Bonn
3
Institut für Geologie, Universität Wien
1
2
The W isotope composition and the Hf/W ratio of the
silicate Earth and the silicate Moon can help to unravel the
relative chronology of the Moon-forming giant impact event
and core formation on Earth. It has been established by now
that the silicate Earth and the Moon are indistinguishable in
terms of their W isotope signature [1]. Yet, it has long been
assumed that the Hf/W ratio of the silicate Moon (26.5 [1])is
higher than that estimated for the silicate Earth (18.7) [2].
Based on these two values and the similar W isotope
composition, a maximum age of the Moon-forming giant
impact has been estimated to ca. 60 Ma after solar system
formation [1]. Here we evaluate new Hf/W estimates of the
silicate Earth and the silicate Moon.
The Hf/W ratio of the silicate Earth has traditionally been
estimated assuming near constant W/Th or W/U and
chondritic Hf/U or Hf/Th ratios [2, 3]. Our recently published
mass balance estimate for W in the silicate Earth challenges
this view, as W has been shown to be highly mobile in
subduction systems. This leads to substantial W/Th and W/U
fractionations in arc lavas/OIBs. An improved mass balance
estimate for the silicate Earth, based on Ta/W systematics in
major silicate reservoirs has yielded a Hf/W of 25.8 [4].
For the Moon, a re-evaluation of existing W-Th-U-Ta data
together with new high precision data yields a Hf/W of 24.9
for the silicate Moon [5], similar within error to previous
estimates. Notably, the lunar value is indistinguishable from
the revised Hf/W for the silicate Earth.
Together with the identical 182W compositions of the
silicate Earth and the silicate Moon [1], the similar Hf/W
ratios now strongly imply that the Moon forming giant impact
might have triggered an efficient metal-silicate reequilibration on Earth. It is therefore likely, that radiogenic
ingrowth of excess 182W in the Earth’s mantle relative to
chondrites largely occurred after the giant impact and is to a
lesser extent an inherited feature from early formed
planetesimals. Morover, the model age for single stage core
formation on Earth may in fact be close in time to the age of
the Moon forming giant impact.
[1] Touboul M. et al. 2007 Nature 450. [2] Newsom H.E. et
al. 1996 GCA 60. [3] Arevalo R. & McDonough W.F. 2008
EPSL 272. [4] König et al. 2011 GCA 75. [5] Münker 2010
GCA 74.
Mineralogical Magazine
www.minersoc.org
Goldschmidt Conference Abstracts
Dynamical properties of CaIrO3
under high pressure from ab initio
calculations
A. MUÑOZ AND P. RODRÍGUEZ-HERNÁNDEZ
MALTA Consolider Team, Departamento de Física
Fundamental II, and Instituto Universitario de Materiales y
Nanotecnologia, Universidad de La Laguna, 38205La
Laguna, Tenerife, Spain ([email protected])
CaIrO3 crystallizes in the orthorhombic Cmcm at normal
conditions. This compound is attracting important interest as a
low-pressure isostructural analog of the predicted
postperovskite high pressure phase of MgSiO3. Here we
perform an ab initio density functional calculations of the
structural and dynamical properties under hydrostatic pressure
for the Cmcm and the Pbnm phase of of CaIrO3.
Our studies have been performed in the framework of
DFT with echange correlation taken in generalized gradient
approximation (GGA) with the PBEsol prescription. We use
the pseudopotential method with ultrasoft PAW
pseudopotentials with an energy cutoff of 520 eV. Such a
large cutoff was required to achieve highly converged results
within the projector augmented wave (PAW) scheme. The
PAW method takes into account the full nodal character of all
the electron charge density distribution in the core region. We
use a dense grid of k-special points for integrations along the
Brillouin zone (BZ) in order to assure highly converged
results.
Lattice dynamics calculations of phonon modes were
performed at the zone centre (P point) of the BZ. The
calculations provided information about the frequency,
symmetry and polarization vector of the vibrational modes in
each structure. We use direct force-constant approach (or
supercell method). Diagonalization of the dynamical matrix
provides both the frequencies of the normal modes and their
polarization vectors. It allows us to identify the irreducible
representations and the character of phonon modes at the P
point. We will report the Raman and IR actives modes, the
pressure derivarives, the phonon dispersion, the phonon
density of states and the projected DOS.
1515
Vertical distribution of iodine in pore
water collected from Japan Sea
sediments: Origin of iodine-rich fluid
associated with methane hydrate
Y. MURAMATSU1, H. ANZAI1, H. TOMARU2,
R. MATSUMOTO2 AND H. MATSUZAKI3
Dept. of Chemistry, Gakushuin University, Toshima, Tokyo,
171-8588, Japan: ([email protected])
2
Dept. of Earth and Planetary Sciences, University of Tokyo,
Bunkyo, Tokyo, 113-0032, Japan
3
Dept. of Nuclear Engineering and Management, University of
Tokyo, Bunkyo, Tokyo, 113-0032, Japan
1
In our previous studies, we have analyzed iodine in many
geochemical samples systematically and found that nearly
70% of iodine in the Earth’s crust is estimated to exist in
marine sediments (Muramatsu and Wedepohl 1998). We also
studied occurrences of iodine rich brine associated with
methane seepage in different areas surrounding Japan
(Muramatsu et al. 2001, 2007).
In this study we have analyzed halogens and some other
elements in pore water samples collected from Japan Sea
sediments of methane hydrate areas. Sediment cores were
recovered from the Umitaka Spur and the Joetsu Knoll region,
eastern margin of the Japan Sea, during the cruises of
Umitaka-Maru in 2009 and R/V Marion Dufresne in 2010
(MD179). The depth of the sediments collected were down to
about 40m below sea floor. Concentrations of iodine, bromine
and some other elements were analyzed by ICP-MS and those
of chloride and sulfate were by ion-chromatography.
Analytical results showed that iodine concentration in pore
water increased markedly with depth. The slope of the
increase was rather constant. The highest concentration found
in the Umitaka Spur was 0.4 mM (about 50ppm) which is
nearly 1000 times higher than the seawater concentration. No
marked increases of iodine were found in the samples
collected from control areas without methane seepage.
We also determined 129I/127I ratios by AMS in pore water
samples at defferent depth. As a result, the 129I/127I ratios
tended to be lower in the deeper layers. The lowest ratio was
about 0.13 x10-12, which was older than 50 Ma. This age is
before the opening event of Japan Sea. Considering the age of
iodine obtained and the depth profile of the iodine
concentrations, iodine and possibly methane are originated
from deeper layers and transported with aqueous fluids into
the surface layers.
This study was supported by MH21 Research Consortium
Japan
Mineralogical Magazine
www.minersoc.org
1516
Goldschmidt Conference Abstracts
Sr, Nd, Hf and Pb isotope
characterisation of basalts from
IODP Site U1346, Shirshov Massif
the youngest edifice of the Shatsky
Rise, northwest Pacific
DAVID MURPHY1*, JÖRG GELDMACHER2
3
AND IRINA ROMANOVA
Discipline of Biogeosciences, Queensland University of
Technology, Brisbane, Qld. 4001, Australia
(*correspondence: [email protected])
2
USIO- IODP, Texas A&M University, College Station, TX
77845-9547, USA
3
Discipline of Biogeosciences, Queensland University of
Technology, Brisbane, Qld. 4001, Australia
1
The Shatsky Rise is a large volcanic plateau in the
northwest Pacific that formed between 140–150 Ma on the
Pacific oceanic crust [1, 2]. Magnetic lineations indicate that
the plateau formed along the trace of a triple junction of
oceanic spreading ridges [1]. Shirshov Massif is the northern
most of the large seamounts within Shatsky Rise. It is a
subcircular edifice, ~100 km in diameter. The Shirshov Massif
represents a waning phase in the evolution of the Shatsky
Rise, intermediate between the main phase of plateau
formation at the Tamu Massif to the southeast and the much
lower levels of magmatism represented by the younger
Papanin Ridge to the northeast. In the parlance of the plume
head hypothesis, Shirshov Massif is in the transition between
plume head and tail.
During IODP Expedition 324 Hole U1346A, situated on
the northern flank of the Shirshov massif, was drilled,
penetrating thin sediment cover and into igneous basement.
Two volcanic units were recognised, a 1.6m volcanic debris
flow and a 50.1m thick succession of pillow lavas (and/or
inflation units) that represent a single volcanic event [3].
Here we present Sr, Nd, Hf and Pb isotope data from the
basaltic basement samples. We compare the isotope data to
previous analyses from the Shatsky Rise [2], to other oceanic
plateaus and to estimated mantle end member compositions in
order to assess the nature of the mantle material that melted to
form the final stage of plateau volcanism at Shatsky Rise.
[1] Nakanishi, et al. (1999) Journal of Geophysical Research
Solid Earth 104, 7539–7556. [2] Mahoney, et al. (2005)
Geology 33, 185–188. [3] Expedition 324 Scientists (2010)
Site U1346. In Sager, W.W. Sano, T. Geldmacher, J. & the
Expedition 324 Scientists, Proc. IODP, 324, Tokyo (IODPMI) doi, 10.2204/iodp.proc.324.103.2010
Mineralogical Magazine
U-Series disequilibrium in
groundwater as a vector for
U mineralisation
MELISSA J. MURPHY1*, ANTHONY DOSSETO2,
SIMON P. TURNER1 AND BRUCE F. SCHAEFER1
GEMOC, Department of Earth and Planetary Sciences,
Macquarie University, Australia
(*correspondence: [email protected])
2
GeoQuEST Research Centre, School of Earth and
Environmental Sciences, University of Wollongong,
Australia
1
Groundwaters often exhibit (234U/238U) activity ratios
greater than one as a result of fractionation between 234U and
238
U nuclides during rock/water interactions. However, when
groundwaters pass through high-grade uranium mineralisation,
congruent dissolution of uranium minerals should impart a
(234U/238U) activity ratio which is at or very close to secular
equilibrium.
This research characterises the uranium-series (U-series)
disequilibria in groundwater surrounding a high-grade
uranium deposit, and investigates the use of disequilibria in
groundwater as a proxy for uranium exploration. U-Series
isotopes have been analysed by isotope dilution MC-ICP-MS
in groundwater samples along the groundwater flow path,
within and surrounding the South Australian Four Mile and
Pepegoona sediment-hosted uranium mineralised systems.
Samples collected down-gradient of the Four Mile
mineralisation have (234U/238U) activity ratios ranging from
1.12 proximal to mineralisation, up to 2.08 approximately 10
kms down-gradient from mineralisation. U concentrations
range from 0.5 – 200 ppb, with highest concentrations found
in samples collected in mineralisation. Groundwaters sampled
within the high-grade mineralisation show (234U/238U) activity
ratios close to unity (1.05), which is consistent with the
congruent dissolution of uranium minerals.
The observation of increasing disequilibrium with distance
from mineralisation highlights the potential application of Useries isotopes as an indicator of high-grade uranium deposits.
However, the extent and distribution of disequilibrium at
the Pepegoona deposit is not entirely consistant with
proximity to the mineralisation. Groundwaters samples within
mineralisation exhibit much higher (234U/238U) activity ratios
than at Four Mile, averaging 1.41. Samples collected downgradient have typically lower U concentrations and (234U/238U)
activity ratios approaching unity. This signature reflects the
highly variable local geology of the Pepegoona deposit.
www.minersoc.org
Goldschmidt Conference Abstracts
Global warming and climate change:
Impact on India
K.S. MURTY
101/28 Hindustan colony, Amaravati Rd., Nagpur 440033,
India (murtysk1931@yahoo. co. in)
Global warming is here to stay and climate change will be
intense. The warming could range from 1.8 dgrees to 4
degrees C. , which could lead to water scarcity and droughts as
well as higher rainfall and floods. The impact will also affect
biodiversity, forests and agriculture. India has seen stupendous
growth in the agricultural sector and has become from oncefood-importing to food-exportring country, after adopting new
technologies and agriculture and its allied industries contribute
to nearly 19 per cent of the total Gross Domestic Product
(GDP). More than 60 per cent of the work force is dependent
on this sector. Nearly two-thirds of the cropped areas in the
region is rain-fed. Apart from this, the northern rivers derive
much of their waters from the Himalayan glaciers. It has been
reported that there has been accelerated rate of melting of
these glaciers. Still higher rate of melting could affect fresh
water supply sources in the Ganga-Brahnmaputra basin which
could directly affect the biodiversity, livelihood of people in
that region and lead to dramatc consequences of the country’s
economy. Hydropower generation could be drastically
reduced, leading to an energy crisis. The country has a
coastline of 6,000 km around which about 400 million people
live. Any rise in the sea level, say by a meter, can lead to
welfare loss of $1.859 million in India. As it is, tropical
cyclones in the Bay of Bengal cause havoc in the coastal areas
and any rise in sea level could mean a loss of 15 per cent of
land area by 2020. Biospheres like the Sunderbans can be lost
for ever and other mangrove forests may meet the same fate.
Forests play a crucial role in the social, economic and cultural
spheres of India. Many river systems originate in the forests
and anchor rich biodiversity. Some 200,000 villages are
located inside or on the fringes of forests and some 200
million people depend on forests for their livelihood. The
Indian subcontinent is projected to experience a warming of 2
to 6 degrees by the end of the current century with
consequences of reduced or increased rainfall, threat to
biodiversity and in general to the rate of growth of its
economy. Urgent steps are needed to face these threats and the
Government of India is grappling with this problem.
Mineralogical Magazine
1517
Direct aerosol effect from multimodel
simulations in AeroCom
G. MYHRE
Center for International Climate and Environmental Research
– Oslo (CICERO), Norway,
([email protected])
There has been a substantially development of the global
aerosol models over the last decade. Despite this development
and advanced aerosol observations uncertainties in the direct
aerosol effect is substantial. AeroCom is a global aerosol
model intercomparison exercise [1, 2] and Phase II
simulations have recently been performed. Here we present
results from several global aerosol models with simulations of
the direct aerosol effect based on aerosol emissions for present
and pre-industrial conditions. The solar radiative forcing (RF)
of the total direct aerosol effect range between -0.6 and -0.05
Wm-2. All models in the study include anthropogenic changes
in sulphate, black carbon (BC) from fossil fuel, organic carbon
(OC) from fossil fuel, and biomass burning aerosols (BC and
OC). Some of the models also include anthropogenic changes
in secondary organic aerosols and nitrate in the model
simulations. The spread in the RF is large for the
carbonaceous aerosols, with RF for BC from fossil fuel
ranging from 0.14 to 0.37 Wm-2. The few models performing
RF of secondary organic carbon and nitrate shows even larger
relative range in the RF.
We analyze the results with respect to burden, aerosol
optical depth, and extinction coefficients to explore the causes
for the differences. Further, vertical profile differences which
are particularly important for BC is quantified in terms of RF.
[1] Schulz, M. Textor, C. Kinne, S. Balkanski, Y. Bauer, S. et
al. (2006) Atmos. Chem. Phys. 5225–5246. [2] Textor, C.
Schulz, M. Guibert, S. Kinne, S. Balkanski, Y. et al. (2006)
Atmos. Chem. Phys. 6, 1777–1813.
www.minersoc.org
Goldschmidt Conference Abstracts
1518
X-ray analysis of reactive C-, N-, P-,
and S-functional groups in NOM
S.C.B. MYNENI
Geochemical monitoring of reactive
percolation experiments using carbon
stable isotopes
A. MYRTTINEN1*, E. JEANDEL2, O. UKELIS2,
ALAIN DIMIER2, V. BECKER1, R. VAN GELDERN1
1
AND J.A.C. BARTH
Department of Geosciences, Princeton University, Princeton,
NJ 08544, USA
NOM plays an important role in many biogeochemical
processes, and the conentration and chemistry of functional
groups of NOM dictate their role in different processes.
Traditional laboratory techniques, such as NMR and IR, have
been used for decades to examine the functional group
composition of isolated NOM. In the last decade, synchrotron
based X-ray absorption spectroscopy (XAS) and
spectromicroscopy methods allowed the examination of
functional groups of NOM in their pristine state in soils and
sediments at nanometer resolution. A discussion of XAS of
reactive functional groups in NOM and their cycling in
terrestrial systems will be presented.
Using XAS, we examined isolated NOM from different
environments, and NOM in selected soils without any
isolation. The XAS of several simple molecules containing
different C-, N-, P-, and S-groups were also examined, and
their spectra helped in interpreting the electronic states of
different functional groups of NOM. X-ray spectra were also
collected in different ways (using electron and fluorescence
yield, and transmission) to identify the best detection schemes.
While several functional groups are identified using XAS,
the ability to detect different C-moieties with X-rays is not as
good as NMR. However, XAS contributes new information on
the aromatic-N, amides, and nitrosyls. The detection of P
groups using XAS is at par with that of NMR. However, small
variations in the XAS of P can be used to detect the bonding
environments of phosphate or phosphonate groups. The SXAS spectra of NOM provide unique information on both the
reduced and oxidized functional groups of S.
The electronic transitions, probed using XAS, are highly
sensitive to small changes in the local coordination
environments of functional groups, and the X-ray spectra
change with changes in the protonation state, metal
complexation (type of metal, and the number of metals), and
symmetry of functional groups. The X-ray spectra are also
sensitive to sample thickness and the concentration of the
reactive groups, which can influence the relative concentration
estimates. Ignoring these variations can result in the incorrect
identification of the functional groups.
Mineralogical Magazine
GeoZentrum Nordbayern, Friedrich-Alexander Universität
Erlangen-Nürnberg, 91056 Erlangen, Germany
(*correspondence: [email protected])
2
European Institute for Energy Research, D-76131 Karlsruhe,
Germany
1
Reservoir
petrophysical
property
changes
(permeability/porosity) are crucial issues, which need to be
considered in carbon capture and storage (CCS) and enhanced
oil and gas recovery (EOR and EGR). The potential
hydrodynamic and geochemical reactions during such
initiatives need to be well understood for planning, as well as
for monitoring purposes. CO2-rock-brine interactions are often
analysed using geochemical parameters such as ion
concentration changes. Stable isotope measurements of carbon
("13C)are currently used as a method to montor and quantify
geochemical changes during CO2-injection. The applicability
of using these isotopes as an additional and new monitoring
tool to verify permeabiliy changes in the host rock has been
tested in a series of laboratory experiments with a new
reactive percolation bench, ICARE 4. Reservoirs, considered
suitable for CO2 injection, often host carbonate phases in
contact with brine. Carbonate dissolution, plays a major role in
host rock permeability changes during CO2 injection. In order
to test the geochemical effects of such a scenario, supercritical
CO2 was injected into brine in contact with quarzitic
limestone. Results indicate good correlations between
permeability, "13C, DIC and calcium concentration data. Once
CO2-breakthrough occurred, permeability increased from a
minimum of 0.1 millidarcy (mD) to a maximum of + 1.4 mD.
This was accompanied by a "13CDIC increase from + -5 ‰ to 0
‰; DIC concentration increase from 0 mg L-1 to 3000 mg L-1
and a calcium concentration increase from below 100 mg L-1
to + 1400 mg L¯. These first data imply that "13C is a valid
monitoring parameter for observing critical geochemical
changes indicating CO2 rock-brine interaction, which may be
used to verify permeability development during CO2 injection.
www.minersoc.org
Goldschmidt Conference Abstracts
P5+ and Ti4+ solution mechanisms of
and partitioning between fluids and
melts at crustal and upper mantle
pressure and temperature
BJORN O. MYSEN
1519
In situ, high-pressure/-temperature
experimental determination of
structure-property relations in
silicate melt-COHN systems
BJORN O. MYSEN
Geohysical Laboratory, Carnegie Instn. Washington, 5251
Broad Branch Rd., NW, USA ([email protected])
Geohysical Laboratory, Carnegie Instn. Washington, 5251
Broad Branch Rd., NW, USA ([email protected])
Solution mechanisms of P- and Ti-bearing, H2O-saturated
silicate melts, silicate-saturated aqueous fluids, and silicaterich single phase (supercritical) liquids have been
characterized in situ to 900°C/2.2 GPa with vibrational
spectroscopy as structural tool. Partitioning of P- and Ti
species between fluid and melt was also determined. Starting
materials were aluminum-free Na2O•4SiO2 (NS4) and with 10
mol % Al2O3 (NA10) substituting for SiO2, with 10 mol %
TiO2 or 5 mol % P2O5. The structure of Ti-bearing aqueous
fluids in equilibrium with rutile was also characterized.
Aluminosilicate species of Qo, Q1, Q2, and Q3 type exist in
coexisting fluid and melt in both Ti- and P-bearing systems. In
melts, the abundance of the most depolymerized silicate
species, Qo, is positively correlated with temperature and
pressure, whereas that of the most polymerized species, Q3,
decreases with temperature and pressure. In the silicate solute
in aqueous fluids, Q3 (and Q1 and Q2) abundance increases
with temperature and pressure. The phosphate species in melts
and fluids are of PO4, P2O7, and QnP type. In the Ti-bearing
silicate systems, isolated TiO4 tetrahedra in melts and fluids
probably share oxygen with neighboring silicate tetrahedra.
The Ti in aqueous fluids in TiO2 (rutile)-H2O comprises
polyhedra with greater oxygen coordination numbers.
The fluid/melt partition coefficients for P2O7 and QnP
species are in the 0.15-0.7 range. The PO4 fluid/melt partition
coefficients are <0.2. These partition coefficients increase with
increasing temperature and pressure. There is no clear
influence of Al2O3. The fluid/melt partition coefficient of Ti in
the equivalent Ti-bearing systems increases from ~0.1 to ~0.5
in the 200°-500°C and 0.4-1 GPa temperature and pressure
range with greater values in Al-bearing systems. The Ti
concentration in aqueous fluids coexisting with rutile in the
same pressure and temperature range is 810% of that in the
silicate systems.
The P-bearing complexes in fluids and melts are
associated with Na+ in the silicate systems, whereas Ti4+ in
silicate systems may form more complex complexes that
involve both Na+ and Al3+. Formation of such complexes can
enhance Ti and P solubility in aqueous fluids can enhance
their solubility by at least and order of magnitude compared
with silicate-saturated systems.
Voletiles in the COHN system, when dissolved in silicate
melts, affect their transport and thermodynamic properties.
Quantitative characterization of solution mechanisms, central
to characterization of melt properties, has been carried out
while melts and coexisting COHN fluids were at the desired
pressure and temperature.
In aluminosilicate melt-H2O, the =H of the water
speciation equilibrium, H2O°(melt) + O (melt)!2OH (melt), is
~30 kJ/mol with =H positively correlated with Al/(Al+Si) of
the melt. This speciation equilibrium coupled with an
appropriate silicate speciation equilibrium becomes, Qn (M) +
H2O ! Qn-1 (H), where (M) and (H) denotes metal cation and
protons associated with nonbridging oxygen. The =H for the
reaction is ~6±2 kJ/mol with a slight positive correlation with
Al/(Al+Si).
In melt-COH and melt-NOH systems, fO2 is an additional
variable affecting solubility and solution mechanisms. From
haplobasalt to haploandesite melt-COH, the carbon solubility
at upper mantle pressures and temperatures decreases from ~2
wt% to ~1 wt% in equilibrium with CO2 gas, whereas under
reducing conditions, decrease is from about 0.3 to about 0.15
wt% in equilibrium with NH4+H2 gas. Oxidized carbon is
dissolved dominantly as CO3 groups, whereas reduced carbon
in the COH system is dissolved as a mixture of CH3 groups
and CH4 molecules. In compositionally analogous NOHsaturated melts, under oxidizing conditions, nitrogen solubity
is insensitive to melt composition, whereas in reduced melts,
the solubility decreases from ~1 wt% to ~0.3 wt% in
equilibrium with NH3 gas in the composition range from
haploandesite to haplobasalt. The solubility increases rapidly
with decreasing fO2. Oxidized N is dossolved as N2 molecules,
whereas reduced nitrogen is dissolved as NH2 groups and
NH3.
By changing fO2 from oxidized to reduced, resultant
changes of C and N solution mechanisms in melt-COHN
systems cause NBO/T changes, which affect transport
properties. For example, melt viscosity under oxidizing and
conditions is, ,=4.4+0.75[0.35-(XCO2/50)]-4.1, whereas under
reducing conditions it is, ,=4.4+0.75[0.35+(XCH4/30.3)]-4.1.
This illustrates how redox conditions alone can change melt
properties relevant to magmatic processes in the Earth’s
interior.
Mineralogical Magazine
www.minersoc.org
1520
Goldschmidt Conference Abstracts
Lithium isotope fractionation at the
soil–plant interface
O. MY'KA1, T. MAGNA1,2, M. NOVÁK1, J. 'IKL1,
V.ZOULKOVÁ1 AND F. OULEHLE1
1
2
Czech Geological Survey, Prague, Czech Republic
Universität Münster, Germany
Lithium abundances and isotope compositions were
determined for an extensively studied site in the KruQné hory
Mts. in order to search for previously unknown stable isotope
fractionations of non-nutrient trace elements between soils and
vegetation cover (Picea sp., Fagus sp.). In the soil profile, Li
contents decrease from ~60 ppm at 40–80 cm depth to 20 ppm
at 0–10 cm depth und to 6 ppm in the uppermost organic layer
(Oi+Oe) whereas sup-ppm Li levels were consistently found
in roots, stem and needles. Stems have the lowest Li contents
of all analyzed tree compartments. The Li contents show tight
positive linear correlation with Mg both in soils and trees but
less defined correlation with other alkali elements (Na, K).
Soil, developed on granitoid bedrock, appears to reflect its
magmatic precursor with only limited modification through
weathering or fluid circulation. Roots of both Picea sp. and
Fagus sp. show no significant difference relative to "7Li of
underlying soils despite different rooting depth (shallow for
Picea, deep for Fagus). In contrast, stem wood of both species
consistently shows significant enrichments in 7Li relative to
roots and soils (cf. [1]); in particular, "7Li difference of >16‰
has been found for Picea stem and roots. It thus appears that
stem may fractionate Li isotopes significantly, irrespective of
botanic classification or taxonomy of the corresponding
species (gymnospermous, angiospermous) but the extent of
this fractionation may depend on qualitative characteristics of
the wood, such as proportion of xylem and phloem, structural
bonding of celulose etc. In either case, the data require more
complex examination of interaction between plants and
substrate with respect to different rooting depths, chemistry,
bottom water flow, nutrient availability etc.
Overall, the results are best explained by low utilization of
Li in biological matter despite modest bioavailability of Li
from grown substrate. Whether or not net 7Li enrichments in
plants are a general feature remains unconstrained but it could
be consistent with positive Li–Mg correlation in plants and
high "26Mg in wheat that has been found to result from
preferential uptake of heavy Mg from the nutrient supply into
plants [2].
[1] Lemarchand et al. (2010) GCA 74, 4612–4628. [2] Black
et al. (2008) Env. Sci. Tech. 42, 7831–7836.
Mineralogical Magazine
www.minersoc.org