INTERNATIONAL WORKSHOP
LEAD ISOTOPES AND
ARCHAEOMETALLURGY:
A PROGRESS REPORT
ABSTRACTS BOOK
19-20 JUNE 2008
FRIBOURG (SWITZERLAND)
INTERNATIONAL WORKSHOP
LEAD I SOTOPES AND ARCHAEOMETALLURGY: A PROGRESS R EPORT
(19-20 JUNE 2008, FRIBOURG, SWITZERLAND)
The organizing committee wishes to thank the following institutions for their support
of the workshop:
Swiss National Science Foundation (SNSF)
Laboratory of Prehistoric Archaeology and Human Peopling History, Department of
Anthropology and Ecology, University of Geneva
Geosciences Department, University of Fribourg
2
INTERNATIONAL WORKSHOP
LEAD I SOTOPES AND ARCHAEOMETALLURGY: A PROGRESS R EPORT
(19-20 JUNE 2008, FRIBOURG, SWITZERLAND)
Program
THURSDAY, 19 JUNE 2008
13h30
Reception
14h00
14h30
15h00
Villa, I.M. Traditional methods for Pb isotope analysis
Klein, S. Modern methods for Pb-isotope analyses
Guénette-Beck, B. Characterization of ores by their lead isotopes
ratios
15h30
Coffee break
16h00
16h30
Cattin, F. and Besse, M. Prehistoric archaeology and lead
isotopes analysis
Stos, S. Database for LIA
17h00
Poster session, aperitif
19h00
Dinner (fondue fribourgeoise)
FRIDAY, 20 JUNE 2008
8h30
9h00
9h30
Monna, F. Anthropogenic lead in peatlands as a marker of early
metallurgical activity
Bode, M., Hauptmann, A. and Mezger, K. Detecting the sources
of Roman lead with lead isotope analysis (LIA)– a case study from
Augustan Germania
Degryse, P. Radiogenic isotopes and the provenance determination of iron artefacts
10h00
Coffee break
10h30
Pernicka, E. Analyses of Cu artefacts
11h00
Final discussion
3
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
Traditional methods for Pb isotope analysis
I.M. Villa, University of Bern, CH
Pb isotopic analyses are increasingly employed in archaeometry in order to clarify the
provenance of metal artifacts.
Natural Pb is comprised of four stable isotopes: 204Pb, 206Pb, 207Pb and 208Pb. Unlike
most other elements, the relative ratios of Pb isotopes to each other are not constant
amongst terrestrial materials. This is because 206Pb and 207Pb are modified by the
radioactive decay of U, and 208Pb is by that of Th. When a base metal deposit is formed
by geological processes, the Pb is separated from U and Th, and its isotopic
composition freezes in two bits of information: the age at which the deposit formed,
and the U/Th element ratio in the precursor rocks of the ore deposit. To a certain extent
this sets apart one deposit from others.
As an example, the Ag-Pb ores of the Cyclades (Greece) were formed in recent
geological times (less than about 20 Ma ago), while the Zn-Pb ores of Sulcis (SW
Sardinia) were formed over 500 Ma ago, during a much more distant geological past.
Accordingly, the Pb isotopic ratios of Greek ores and Sardinian ores are very different.
Metal artifacts deriving from Greek mining have therefore a very distinct “Pb isotopic
fingerprint” from that of Phenician mining in Sulcis. Reconstructing trade routes is
thus made possible by identifying the provenance of metal ores.
Note that dating the geological event that produced the ore is not equivalent to
determining the metallurgical event of smelting; the latter does not modify the Pb
isotopic composition. The age of a metal object cannot be determined using isotope
techniques.
Because geological events take place over large distances, it is a fact that “geological
provinces” share a common evolution, and dozens of close-by ore bodies end up
having very similar Pb isotopic fingerprints. Examples are the Cyclades, the Valais
(Switzerland), the mining districts all over the Deutsches Mittelgebirge (Germany), etc.
Nota bene that for a geologist it is difficult to answer if the sample came from the
Laurion mines or from Siphnos, while a historian may see an immense political
difference between the two.
Sometimes, individual mines show very subtle differences which can be analytically
resolved, provided one has a high-precision instrument; as an example, the local ore
production from the Valais in prehistoric and medieval times (see contribution by B.
Guénette-Beck) can be subdivided into sub-districts using plasma ionisation
multicollector mass spectrometry (PIMMS). The most important limiting factor at
present is the still incomplete data basis on the hundreds of small and smallest ore
mines that have been exploited during our past. An analytical approach that allows a
high data throughput is, again, PIMMS.
Until the data-base is completed, there will be ample possibilities for mis-attributions
due to missing information; however, even with an infinitely precise and complete
data-basis it is unavoidable that geological processes do not respect political or ethnic
boundaries, and thus the geological fingerprinting will always leave room for
ambiguities in trade route reconstructions.
A further challenge is the transition to improved metallurgy, which led to lower
concentrations of contaminants such as Pb. The requirement by museum curators to
consume little material of a precious exhibit must be conciled with need for precise
analyses; sometimes, even the highest sensitivity and precision available today (PIMMS)
is barely sufficient, and a new generation of more sensitive and more precise mass
spectrometers would be desirable.
4
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
Characterization of ores by their lead isotope ratios
Barbara Guénette-Beck, Geosciences, University of Fribourg, CH
To trace the origin of metals with the help of lead isotopes: the efficiency of this
method is well proven. Questions arise about the quality of information available on
the mines and mining districts supplying the metal. How to characterise a mine by its
lead isotope ratios?
First of all, we have to fix the type of mineralization. Lead isotope data of a
hydrothermal or metamorphic vein are plotted, in the usually used diagrams, not in
one point but follow a linear trend. This is not necessarily the case for placer ore bodies
and those of the MVT (Mississippi Valley Type), where the relationship between ore
body to host rock is different.
Second, we have to distinguish between the characterization of a mineralization and
that of a mine. One mine can be formed quite by more than one mineralization event.
Accurate field work sometimes permits to determine more than one event.
Third, the characterization of an ore body depends mainly on the investigated ore type
– namely lead/silver ores, copper ores, etc. Indeed, it is proven that metallurgical
procedures do not modify the lead isotope ratio from ore body to the artefact.
However, the influence of the host rock is still not clear: it is certainly insignificant for
lead rich ores like lead/silver ores, but probably not so for lead poor ores like for copper
ores. Parts of the host rock, which are not well separated, and/or added fluxes can
modify the lead isotopes ratios of the ore.
Regarding the complexity of an ore body, the question arises about the standard of the
field work necessary for sampling and the quantity of samples required for obtaining
relevant data.
5
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
Prehistoric archaeology and lead isotopes analysis
Cattin, F. and Besse, M.
Laboratory of Prehistoric Archaeology and Human Peopling History, Department of
Anthropology and Ecology, University of Geneva
Lead isotopes analysis can be used in archaeology to provide answers to a number of
questions. Since the late 60s, the approach is to use the fingerprint of lead isotopes
from ore deposits and to compare it to the one of metal objects. Topics as economy,
social contexts of the metal production (Gale et al. 2000), technology transfer (StosGale 1989) and modes of usage (Guénette-Beck 2005) have been investigated.
Our study focuses on human peopling during the third millennium BC. It takes place
within the framework of a research program initiated several years ago ― under the
supervision of Marie Besse (Swiss National Science Foundation SNSF proposals 101412
-100599, PP 001-102710 et GE-112885) ― using several points of view: common
ware, radiocarbon dating, territory analysis, anthropology using non-metric dental
traits, copper metallurgy, and the lithic industry (Piguet et al. 2007).
Our research (Cattin, in progress) is based on copper objects from Pre-Bell Beaker, Bell
Beaker, and Post-Bell Beaker periods, using the elemental chemical composition and
the lead isotopes analysis. The aim of this part of the study is to answer two questions:
- Is there a difference in copper supply for these three periods?
- Is it possible to trace the provenance of copper?
We seek to interpret the results in terms of human peopling.
References
Cattin, F., (in progress). La métallurgie du cuivre dans les Alpes au 3e millénaire avant J.-C. Université de
Genève: Dép d’anthrop. et d’écologie de l’Univ. (PhD thesis).
Gale, N. H., Stos-Gale, Z. A., Radouncheva, A., Ivanov, I., Lilov, P., Todorov, T. et Panayotov, I., 2000.
Early metallurgy in Bulgaria. In: Annuary of department archaeology, volume 4-5. Sofia, New
bulgarian University, Institute of archaeology with museum, Bulgarian academy of sciences, 102168.
Guénette-Beck, B., 2005. Minerais, métaux, isotopes: recherches archéométriques sur les mines de
plomb et d’argent en Valais, Suisse. Université de Lausanne: Faculté des Sciences (PhD thesis).
Piguet, M., Desideri, J., Furestier, R., Cattin, F. et Besse, M., 2007. Populations et histoire des
peuplements campaniformes: chronologie céramique et anthropologie biologique. In: Besse, M.,
éd, Sociétés néolithiques: des faits archéologiques aux fonctionnements socio-économiques,
Lausanne, Cahs d’archéol. romande. Actes du 27e colloque interrégional sur le Néolithique
(Neuchâtel ; 1-2 oct. 2005), (Cahs d’archéol. romande ; 108), 249–278.
Stos-Gale, Z. A., 1989. Cycladic copper metallurgy. In: Hauptmann, A., Pernicka, E. et Wagner, G. A.,
éds, Archäometallurgie der Alten Welt: Beiträge zum Internationalen Symposium "Old World
archaeometallurgy", Heidelberg 1987 = Old World archaeometallurgy: proceedings of the
International Symposium "Old World archaeometallurgy", Heidelberg 1987, Bochum, Selbstverl.
des Deutschen Bergbau-Museums. International Symposium "Old World archeometallurgy"
(Heidelberg ; 1987), (Der Anschnitt ; Beiheft 7)(Veröffentlichungen aus dem Deutschen BergbauMuseum Bochum ; 44), 279–291.
6
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
Anthropogenic lead in peatlands as a marker of early metallurgical activity
Fabrice Monna, University of Bourgogne, F
With agricultural developments, mankind’s quest for metals is a key question to
understand the organisation of prehistoric civilizations. Most of the time, the study of
metal production is tackled by investigating artefacts found sporadically in hoards and
graves because, except for some exceptional discoveries, early mining remains have
been destroyed, buried or masked by further metal extraction, up to and including that
of the 20th century. On the basis of this fragmentary information, it was nonetheless
established that metalworking first propagated in Europe from East to West, to simplify
from the Balkans to the North Alpine Arc, and finally to Western Europe. During the
Bronze and Iron Ages, metalworking developed in some particular centres of medium
or slight importance until Antiquity when metal production increased considerably.
Besides this general and well-accepted scheme, the reconstruction of mining and
metallurgical history at a particular place may be envisaged through an environmental
approach in the absence of direct archaeological evidence. The basic idea is that
anthropogenic activities have caused the deposition of heavy metals in the surrounding
environment, and that this contamination may have been recorded in sediments or
peatlands. Ombrotrophic peat bogs are nonetheless considered as the most
appropriated media for such a purpose because they are almost only fed by the
atmosphere, so that their geochemical background is low. Metals buried in peatlands
may however result from a combination of multiple sources, while postdepositional
migrations, already observed at decadal scale, may totally preclude any utilization for
historical reconstruction. That is why lead isotopic composition, which can help to
dispel such ambiguities, is often determined; lead also possesses the advantage of
being one of the less mobile metals in such an environment. Mining may also have
affected nearby vegetation through possible deforestation performed in response to
increasing energy demands for metalworking. Geochemistry is therefore sometimes
supplemented by pollen analyses.
After a general overview of the existing approaches and techniques, two examples of
historical reconstruction of mining will be presented. Special emphasis will be laid on
the strengths and weaknesses of the overall method.
7
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
Detecting the sources of Roman lead with lead isotope analysis (LIA)– a case
study from Augustan Germania
Michael Bode1, 2, Andreas Hauptmann2, Klaus Mezger1
1
Institut für Mineralogie, Münster & Zentrallabor für Geochronologie (ZLG)
2
Deutsches Bergbau-Museum, Department Archaeometallurgy, Bochum
In Roman time, lead played an important role in military and in everyday life. Before,
lead was mainly regarded as refuse from silver production. To supply the huge need for
lead metal (and also for silver) in the Imperium Romanum, exploration went hand in
hand with the conquests. This seemingly had resulted in a fairly coherent order with
respect to the economically dominating mining regions.
During the Roman Republic, the Iberian mines were controlling the lead metal trade
within the Roman provinces. This study concentrates on the lead metal logistics during
the campaigns in Germania Libera by Augustus and Tiberius from 12 BC to 16 AD.
There are strong hints that directly after the arrival of the Roman troops at the river
Rhine lead-/silver(?) production started in the Eifel area [1, 2, 3]. Another Roman
mining site with lead-/silver production is located in the Bergisches Land east of
Cologne and is dated to the first two decades AD [4]. Additionally, the Sauerland
region northwards has recently been suggested as a further local lead-/silver(?) source
at that time [5].
To identify the ores involved in the lead metal supply and their importance, Pb-isotopes
from a total of 150 lead objects from camps in Germania Libera were determined [2, 6].
The huge number of analyses, which also included analyses of mixed lead, provides
important constraints on the significance of each individual ore deposit exploited at
that time. LIA of some lead objects gave rise to the suggestion that the soldiers, who
came from the Gallic provinces, were equipped with lead from Iberia. However, the
great number of analyses points to the ores in Germania as a primary source. This
paper will present the LIA of the Roman lead objects in comparison with the LIA of the
potential lead ores while taking into account the historical and archaeological
background.
References
[1]
[2]
[3]
[4]
[5]
[6]
Rothenhöfer, P. (2005), Kölner Studien zur Archäologie der Römischen Provinzen 7, 320pp.
Durali-Müller, S. (2005), Dissertation Universität Frankfurt am Main, 128pp.
Bode, M., Hauptmann, A., Mezger, K. (2007), Soester Beiträge zur Archäologie 8, 105-124.
Körlin, G. & Gechter, M, (2003), Der Anschnitt, Beiheft 16, 237-248.
Hanel, N. & Rothenhöfer, P. (2005), Germania 83, 52-65.
Bode, M. (submitted), Dissertation Westfälische Wilhelms-Universität Münster, 275pp.
8
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
Radiogenic isotopes and the provenance determination of iron artefacts
Patrick Degryse
Section Geology, Earth and Environmental Sciences, K.U.Leuven, BE
In the study of ancient iron production and processing, it remains notoriously difficult
to establish the origin of the raw materials of iron artefacts on the basis of main and
trace element contents (Gale and Stos-Gale 1982, Pernicka 1987, Heimann et al. 2001).
Due to effects of chemical fractionation between metal and slag that occur during iron
production, it is difficult to correlate slag, bloom, iron object and ore (Buchwald and
Wivel 1998). Conversely, radiogenic isotopes (e.g. Pb – lead and Sr - strontium) are not
fractionated during the smelting process and the isotopic composition of a metal
artefact is identical to that of the (mixture of) raw material(s) from which it was produced.
Therefore, radiogenic isotopes have been extensively used in archaeometry to trace the
provenance of metals, especially in the study of bronze (e.g. Gale and Stos-Gale, 1982),
but also for other artefacts, such as glass (e.g. Degryse and Schneider 2008).
Due to analytical difficulties with the generally low Pb contents of iron artefacts, lead
isotopes have been rarely employed for the provenance determination of iron ores (Gale
et al. 1990, Schwab et al. 2003). The potentially large variation in chemical composition
of iron ores is a general problem in such provenance studies. Isotope signatures can vary
much for one and the same ore and distinct ore districts may considerably overlap in
isotopic composition. However, using state-of-the-art multi-collector techniques for lead
isotope analysis and a thorough geological knowledge of the potential iron ores
involved in a study, still provide much potential for the use of lead isotopes in iron
provenancing. Moreover, in a pilot study, next to lead also strontium isotope analyses
were performed on Roman to Byzantine iron artefacts and ores from the territory of
Sagalassos, SW Turkey (Degryse et al. 2007). It could be demonstrated that Sr isotopes
are much less ambiguous than Pb isotopes in providing coherent signatures for ore
and related iron. In this way, a combination of several isotopic techniques may give
additional analytical potential to solve the provenance of ancient iron artefacts.
References
Buchwald, V. F., and Wivel, H., 1998, Slag analysis as a method for the characterisation and
provenancing of ancient iron objects, Materials Characterisation, 40, 73-96.
Degryse, P., and Schneider, J., 2008, Pliny the Elder and Sr-Nd isotopes: tracing the provenance of raw
materials for Roman glass production, Journal of Archaeological Science, 35, 1993-2000.
Degryse, P., Schneider, J., Kellens, N., Muchez, Ph., Haack, U., Loots, L., and Waelkens, M., 2007,
Tracing the resources of iron working at ancient Sagalassos: a combined lead and strontium
isotope study on iron artefacts and ores, Archaeometry, 49 (1), 75-86.
Gale, N. H., and Stos-Gale, Z., 1982, Bronze Age Copper Sources in the Mediterranean: a New
Approach, Science, 216, 11-19.
Gale, N. H., Bachmann, H. G., Rothenberg, B., Stos-Gale, Z. A., and Tylecote, R. F., 1990, The
adventitious production of iron in the smelting of copper, in: Researches in the Arabah 19591985, (eds. B. Rothenberg, H.G. Bachmann), University College, London.
Heimann, R. B., Kreher, U., Spazier, I., and Wetzel, G., 2001, Mineralogical and chemical investigations
of bloomery slags from prehistoric (8th century BC to 4th century AD) iron production sites in
Upper and Lower Lusatia, Germany, Archaeometry, 43, 227-252.
Pernicka, E., 1987, Erzlagerstätten in der Ägäis und ihre Ausbeutung im Altertum: Geochemische
Untersuchungen zur Herkunftsbestimmung archäologischer Metallobjekte, Jahrbuch des RömischGermanischen Zentralmuseums Mainz, 34, 607-714.
Schwab, R., Höppner, B., and Pernicka, E., 2003, Studies in technology and provenance of iron
artefacts from the Celtic Oppidum of Manching (Bavaria), Proceedings of the International
Conference on Archaeometallurgy in Europe, 24 to 26 September 2003, Milan, Italy, 545-554.
9
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
LIST OF PARTICIPANTS
Anhäuser, Killian
Musée d'Art et d'Histoire, Genève, CH
[email protected]
Besse, Marie
Laboratory of Prehistoric Archaeology and Human Peopling History, Department of Anthropology and
Ecology, University of Geneva, CH
[email protected]
Bode, Michael
Erdwissenschaften, Universität Münster, D
[email protected]
Cattin, Florence
Laboratory of Prehistoric Archaeology and Human Peopling History, Department of Anthropology and
Ecology, University of Geneva, CH
[email protected]
Cevey, Christian
Swiss National Museum, Affoltern am Albis, CH
[email protected]
Chiaradia, Massimo
Department of Mineralogy, University of Geneva, CH
[email protected]
Degryse, Patrick
Section Geology, Earth and Environmental Sciences, K.U.Leuven, Celestijnenlaan 200E, bus 2408, BE3001 Leuven, Belgium
[email protected]
Forel, Benoit
UMR 5594 CNRS ARTeHIS, Archéologie, Terre, Histoire, Sociétés, UFR Sciences Terre - Université de
Bourgogne, 6 Bd Gabriel, Bât. Sciences Gabriel, 21000 Dijon, F
[email protected]
Giunti, Ilaria
Dipartimento di Geoscienze, Via Giotto, 1, 35137 Padova, I
[email protected]
Guénette-Beck, Barbara
Geosciences, University of Fribourg, CH
[email protected]
Hauptmann, Andreas
Deutsches Bergbaumuseum Bochum, D
[email protected]
Hubert, Vera
Swiss National Museum, Affoltern am Albis, CH
[email protected]
Hunger, Katja
Swiss National Museum, Affoltern am Albis, CH
[email protected]
Katona, Ildiko
Geosciences, University of Fribourg, CH
10
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
Klein, Sabine
Geowissenschaften, Frankfurt am Main, D
[email protected]
Lhemon, Maelle
Geosciences, University of Fribourg, CH
[email protected]
Lockhoff, Nicole
Curt-Engelhorn-Centre for Archaeometry, Mannheim, D
[email protected]
Meier, Stefan W.
Schlossmattstrasse 9, 8934 Knonau
[email protected]
Monna, Fabrice
Laboratoire Géosol, Université de Bourgogne, Bât. Gabriel, 21000 Dijon, F
[email protected]
Pernicka, Ernst
Archäometrie, Uni Tübingen, Mannheim, D
[email protected]
Petit, Christophe
Sciences Terre, Université de Bourgogne, Dijon, F
[email protected]
Prange, Michael
Deutsches Bergbaumuseum Bochum, D
[email protected]
Sarah, Guillaume
IRAMAT - Centre Ernest Babelon, Univeristé d'Orléans
[email protected]
Schaer, Andrea
Kantonsarchäologie Aarau, CH
[email protected]
Serneels, Vincent
Geosciences, University of Fribourg, CH
[email protected]
Soulignac, Raphaelle
Geosciences, University of Fribourg, CH
[email protected]
Stos, Sophie
Research and Business Services Manager - EU Research and Enterprise Support (RES), Uni. of Surrey
[email protected]
Ströbele, Florian
Geowissenschaften, Uni Tübingen
[email protected]
Villa, Igor M.
Labor für Isotopengeologie, Universität Bern
[email protected]
Wichser, Adrian
EMPA Dübendorf, CH
[email protected]
11
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
SCIENTIFIC AND ORGANISING COMMITTEE
Michael Bode, Geosciences, University of Munster, D
Marie Besse, Laboratory of Prehistoric Archaeology and Human Peopling History,
Department of Anthropology and Ecology, University of Geneva, CH
Florence Cattin, Laboratory of Prehistoric Archaeology and Human Peopling History,
Department of Anthropology and Ecology, University of Geneva, CH
Barbara Guénette-Beck, Geosciences, University of Fribourg, CH
Vincent Serneels, Geosciences, University of Fribourg, CH
12
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
Notes
13
LEAD ISOTOPES AND ARCHAEOMETALLURGY : A P ROGRESS R EPORT (19-20 JUNE 2008, FRIBOURG , S WITZERLAND )
Notes
14