Iowa State University
From the SelectedWorks of Cinzia Cervato
April, 1998
Changing depth distribution of hiatuses during
the Cenozoic
Cinzia Spencer-Cervato, University of Maine
This work is licensed under a Creative Commons CC_BY-NC-SA International License.
Available at: http://works.bepress.com/cinzia_cervato/19/
PALEOCEANOGRAPHY,VOL. 13,NO. 2, PAGES178-182,APRIL 1998
Changing depth distribution of hiatusesduring the Cenozoic
Cinzia Spencer-Cervato
Department
of Geological
Sciences
andInstitute
forQuaternary
Studies,
University
ofMaine,Orono
Abstract. The differentialeffectsof climatechange,sealevel;andwatermasscirculation
on deposition/erosion
of
marine sedimentscan be constrainedfrom the distribution of unconformitiesin the world's oceans. I identified
temporal
anddepth
paRems
ofhiatuses
("hiatus
events")
froma largeandchronologically
wellconstrained
stratigraphic
database
of deep-sea
sediments.
ThePaleogene
is characterized
by few,several
millionyearlonghiatuses.
Themost
significant
Cenozoic
hiatuseventspans
mostof thePaleocene.
TheNeogene
ischaracterized
by short,freque
m hiatus
events
nearlysynchronous
in shallow
anddeepwatersediments.
Epochboundaries
arecharacterized
bypeaksin deep
waterhiatuses
possibly
caused
by anincreased
circulation
of corrosive
bottomwaterandsediment
dissolution.
The
Plio-Pleistocene
is characterized
by a gradualdecrease
in thefrequency
of hiatuses.
Futurestudies
will focusonthe
regionalsignificance
of thehiatuseventsandtheirpossible
causes.
1.
Introduction
While it is well acceptedthat the Cenozoic stratigraphic
record on continental margins is punctuatedby numerous
gaps[e.g., Vail et al., 1977; Miller et al., 1990], many studies
have also identified regional unconformitiesin deep-sea
sediments [Keller and Barron, 1983; Osborn et al., 1983;
Keller et al., 1987;Barron, 1989;Aubry, 1991, 1995;Ramsay
et al., 1994]. This paperpresentsthe resultsof a studyof the
distributionof hiatusesduring the Cenozoic and is based on
chronologicallywell constrainedDeep Sea Drilling Project
(DSDP) and OceanDrilling Program(ODP) sections.Compared
to previous compilations of hiatus distribution in the DSDP
stratigraphicrecord [e.g., Moore et al., 1978], this curvehas a
better resolution (0.5 m.y.), containsmore recent holes with
better recovery, and is basedon a more reliable and updated
biochronology (biostratigraphy and magnetostratigraphy)
[Berggrenet al., 1995b].
Among the various causes of hiatuses (erosion, dissolution, corrosion,and nondeposition),the rate of sedimentsupply versusdissolution(corrosion)of sediments,which is controlled by fluctuations in the calcite compensationdepth
(CCD) as well as shallow to deep water sedimentfractionation
[Berger, 1970], is a very significant factor for hiatusesin
deep-watersediments.This relationshiphas beendiscussedin
detail by Keller and Barron [1987].
I have decided to avoid the temptation to speculateabout
the causesof the hiatusesshown in this study becauseof the
genericpresentationof the data in this study.However,I have
included in this paper two published curves of sea level
fluctuations:the sea level curve of Haq et al. [1987] and the
benthic oxygen isotopecurve of Miller et al. [1987]. These
curves will be mainly used to suggestpossibleuses of the
hiatus curve and introduce the future developmentsof this
study.
2. Methodology
database(Figure 1)[Lazaruset al., 1995]. The chronologyof
each hole is based on biostratigraphicand magnetostratigraphicdata publishedin the DSDP Initial Reportsand ODP
Scientific Reports(Lazarus et al. [1995] for NeogeneDSDP
holes). Graphic correlation[Shaw, 1964; Lazarus, 1992] was
used to constructage versusdepth plots for each hole and to
obtain a combined chronology. Calibrated biostratigraphic
and magnetostratigraphic
eventswere used to draw a line of
correlationusing criteria defined to minimize subjectivebias
and guaranteeconsistency.Local biostratigraphiccalibrations
and reliable events(i.e., synchronouswithin the accuracyof
the method [Spencer-Cervato et al,, 1994]) were used for
Neogene sections. Locally calibrated events of siliceous
plankton (diatoms and radiolarians [Baldauf and Barron,
1991; Caulet, 1991; Harwood and Maruyarna, 1992])augmented by biozonations [Fenner, 1984; Sanfilippo et al.,
1985; Sanfilippo and Nigrini, 1995, also unpublisheddata,
1995], and biochronological events of calcareousplankton
(foraminifera and calcareousnannoplankton[Berggrenet al.,
1995a, b]) were usedto constrainthe stratigraphiccorrelation
of Paleogenesections.All events and biozone boundaries
were calibratedto the timescaleof Berggrenet al. [1995b].
Stratigraphicunconformitieswere identified by biostratigraphicand magnetostratigraphic
eventsclusteredin a narrow
depth interval (from less than one sample spacing up to a
maximum of one core length for each inferred event) in intervals of continuouscore recovery. One hundred and thirteen
holes showed evidence of at least one hiatus, and close to 300
hiatusesin all were recognizedin theseholes(Table 1)•. The
holes includedin this study were drilled in a broad range of
depths,both on shelvesand in deep-seaareas(Figure 1) with
the majority of holes (77%) between 1000 and 4000 rn present-daydepth. These sites representa random subsetof the
DSDP andODP holesdrilledthusfar (Z2= 9.68;DF = 6; p <
0.05). Hiatuses are equally distributed through the whole
depth range of the studiedholes (79% of holes with hiatuses
are between1000 and 4000 rn depth;Z2= 1.33;DF = 6; p <
The datapresented
herewere obtainedfrom 166 globally 0.05). However, shallow water sediments(shallowerthan
distributed DSDP and ODP holes included in the Neptune
Copyright1998by theAmericanGeophysical
Union.
I Table1 is available
electronically
at WorldDataCenterA for
Paleoclimatology,
NOAA/NGDC,Boulder,
Colo.(e-mail:
[email protected].
gov;URL:http://www.noaa.
gov/paleo).
PaperNumber97PA03440.
0883-8305/98/97PA-03440512.00
178
SPENCER-CERVATO: DEPTH DISTRIBUTION OF CENOZOIC HIATUSES
75
179
75
60
60
45
45
./
30
30
15
/
,/
/
/
!
,
!
0
e3
/
.-'
[ 4
'2
..................
\
30
%...
30
6O
6O
75
75
Figure1. Mapof location
of DeepSeaDrillingProject
(DSDP)andOceanDrillingProgram
(ODP)holesin theNeptune
database.Dots showholeswherehiatuseswere recorded,and the numbersrepresentthe numberof hiatusesat that location.
Squaresmark holeswhereno hiatuseswere found.Note the highernumberof hiatusesrecordedat high latitudesand on
continental shelves.
1000 m) are underrepresented
in the DSDP and ODP holesand
are, therefore,also not well representedin this dataset.
Sedimentationhiatusescan be causedby mechanicalerosion, by dissolution (corrosion) or by nondeposition.
However, other "artificial" causesof hiatuses(e.g., core recovery) are consideredfirst.
Apparent hiatusesor an extendedduration of hiatusescan
be causedby incompleterecoveryof sedimentsduring coring
[Aubry, 1995]. To test if hiatuseswere more frequent in
poorly recoveredholes,I have comparedthe percentagerecovery versusthe numberof hiatusesrecordedin eachhole. The
lack of correlation(r 2= 0.009) indicatesthat incompleterecovery is not an apparentcause for the hiatuses.However,
sediment can be lost at core breaks in continuously cored
sections,and lossesof up to 12% are reported[deMenocal et
al., 1991; Farrell and danecek,1991]. Particularcare was used
to avoid placinga hiatusnear or duringan intervalof no recovery.Multiple evidencewas requiredin orderto identify a
hiatus (e.g., missingbiozonesand/or magneticreversalsreported by the author(s)of the report and agreementof more
than one biostratigraphicreport). Moreover, hiatusesshorter
than the averagesamplespacingof the bulk of the DSDP and
ODP biostratigraphicdata included in Neptune (0.18 m.y.
[Spencer-Cervato
et al., 1994]) were not considered.
However,
the possibilitythat someof the hiatusesidentifiedin this
work are artificial or artificially lengthenedcannot be excluded.For this reason,I havechosento analyzeand correlate
a large numberof holeswith different recoveryrates and a
global distribution.This integratedapproachis intendedto
minimize any bias [Aubry, 1995].
To obtain a temporal distributionof hiatuses,I calculated
the numberof the holeswhich recordedeach hiatususinga
0.5 m.y. samplinginterval. The choiceof the time intervalwas
a conservativeestimatebasedon the reliability of the age
model (_+0.37m.y. [Spencer-Cervatoet al., 1994]). The results
are plottedin Figure2b. The frequencyof hiatuses(percentage
hiatusesin sectionsanalyzed; Figure 2c) was calculatedto
eliminate
the bias of the uneven distribution
of sections
through the time interval analyzed [see Moore et al.,
1978](highernumber in the late Miocene-Pliocene;Figure
2a). I consider this statistical distribution as an estimate of
the relativeimportanceof hiatuseventsthroughtime, regardless of causal mechanisms. While both data sets were evalu-
ated, it is the patternof hiatusfrequencies
that will be mainly
discussedin this paper. The data presentedin this study,the
oxygen isotopecurve [Miller et al., 1987] (Figure 2e) and the
sealevel curve [Haq et al., 1987] (Figure2d), are all calibrated
to the Berggren et al. [1995b] timescale.
Deep water sedimenthiatusescan be causedby dissolution/corrosion
linked to shallower CCD and intermediate and
deep circulation changes[e.g., Keller and Barron, 1983;
Mayer et al., 1986]. Deep water hiatuses,however, can also be
caused by erosion by deep water currents linked to climate
changesor nondeposition[Ramsayet al., 1994]."'Kellerand
Barron
[1983] identify deep-sea erosional hiatuses
(attributed to glacio-eustaticsea level lowstands)and dissolution hiatuses(during sea level highstands,causedby shallower CCD) that remove previouslydepositedsediments.Two
contrastingmodelshave been presentedto explain deep water
hiatuses: increased deep water production and corrosiveness
during glacial periods [Keller and Barron, 1983] or
nonglacial(deglaciatedor decreasedglaciationin Antarctica)
intervals [Ramsay et al., 1994]. While dissolution can be
sometimes identified in seismic lines [e.g., Mayer et al.,
1986], no direct means of distinguishing between erosion,
nondeposition,and corrosionhas been found yet. The concen-
180
SPENCER-CERVATO:
DEPTHDISTRIBUTIONOFCENOZOICHIATUSES
Number
0
20
4O
of sections
60
80
100 120
Frequencyof hiatuses
Number
ofhiatuses
0
10
20
30
(in%oftotal
sections)
0
20
40
60
80
•j180 %obenthic
"Eustatic" curve
ofHaqetal.,1987
200
100
0
- 100
Miller et al., 1987
0
1
2
3
20
25
•
35
50
60
I
0 20 40 60 80100120 0 1•) 2; 3; 40
0 20 40 60 80
200 100 0 -100 -1 0 I 2 3
a
b
c
d
Figure2. (a) Number
of Cenozoic
DSDPandODPsections
per0.5m.y.in theNeptune
database.
(b) Number
of hiatuses
recorded
in theNeptune
database
during
thelast65m.y.(thisstudy).
(c)Curveof thefrequency
of hiatuses
(thisstudy).
The
verticallinerepresents
theaverage
frequency
(30%).Shaded
intervals
markperiods
characterized
by a higherthanaverage
frequency
of hiatuses
(hiatusevents).
(d) "Eustatic"
sealevelcurveof Haqet al. [1987].(e) Benthic
foraminifera
oxygen
4
isotopecurve[Miller et aL, 1987].
tration of cosmogenicisotopesat hiatusescan potentially
enable us to distinguish between nondepositionand erosion/corrosion(G. Ravizza, personalcommunication,1997).
The resultsfrom this study could be used to identify locations and intervals suitablefor testing this method;however,
no publishedstudiesare availableat the present.
3.
limitedto the 106-to 107 yearscaleevents.As a startingpoint
Results
On average,30% of the sectionsanalyzedcontainany particular hiatus. In the hiatus frequency curve (Figure 2c),
various
hiatus events can be identified
as intervals
with
higherthan averagehiatusfrequency(>30%)(shadedintervals
in Figure2c). Theyoccurwithintwo intervals
fromthebaseof
the Paleocene.The first interval(65-25 Ma) showssparsehia-
tus eventsof long duration(severalmillion years).Within
this intervalone sustained
peakin hiatuses,spanning
mostof
the Paleocene
andpeakingat 62 Ma, is recorded
in up to 70%
of the sectionsanalyzed.This hiatusis the mostsignificant
one in the Cenozoic.The secondinterval (25-0 Ma) showsa
higherfrequency
of severalshorthiatuses.
The last4 Ma are
characterized
by a sharpdeclinein theoccurrence
of hiatuses.
4.
Discussion
reveal the cause of unconformitiesthat define stratigraphic
sequences.Miller et al. [1996], on the otherhand,have shown
that this correlationis possiblelocally, even at a resolutionof
0.5 m.y. Becausethe resolutionof Haq et aL's [1987] recordis
-1 m.y. or worse [Browning et aL, 1996] and the benthicisotopic record of Miller et aL [1987] is also a low-resolution
record, future, more detailed analysisof this data set will be
to determinethe validity of this data set and to identify what
needs to be tested next, I have limited the discussion in this
paperto a very shortanalysisof global patternsof the temporal extent of hiatuses.
To help in the interpretationof the record,I have estimated
the paleo-water depth for the base of each hiatus in this
dataset [Sclater et aL, 1985] (Table 1). Simple backtracking
calculations were used to calculate paleodepth for sites on
oceanic crust. On the basis of a comparisonwith published
data, precision for Neogene sedimentsis -•100 m [Sclater et
al., 1985], while it decreasesto a few hundredmeters at best
for the Paleogene.For detailson the method,see$clater et al.
[1985].
Paleodepthestimatesfor sites on continentalshelves,or in
forearc or intra-arc basins,were not attempted,and present-day
water depth was used instead.This approximationshouldnot
sensiblyaffect the data. Paleodepthintervalsfor this study(02000 m, 2000-3000 m, and deeperthan 3000 m) were selected
Correlationof "wiggly"linesat stratigraphic
scalecanbe
fortuitous,and muchof the correlationmay represent
coincidence.Miall [1991] has arguedthat stratigraphic
resolution to include all continental shelf data into the shallow water
maynotbe sufficiently
accurate
to eitheruniquelyidentifyor category,and I expect water depthto have been within this
SPENCER-CERVATO:
DEPTHDISTRIBUTION
OFCENOZOIC
HIATUSES
depthrangealso in the past. Depthsin forearcand intra-arc
basinsfall largelyinto the deepestcategory.
The subdivision of hiatuses in water depth intervals
(Figure3) showsthat the earlyPaleocene
hiatusesoccurredin
the shallowestwater groups(on continentalshelvesor young
oceaniccrust;Figures3a andb). The CCD wasshallowduring
the Paleocene-Eocene(-•3500 m [van Andel, 1975]) which
might have causedwidespreaddissolutionof carbonatesedi-
181
eventsof Keller and Barron [1987], and were interpretedby
them to correlatewith a sea:levellowstand,high carbonate
dissolutionin deep-seasedimentsand polar cooling.
The early middle Miocene (16 to 15 Ma) is markedby the
absenceof deep-waterhiatusesfollowed by a progressive
increase(Fig. 3c). This correlateswith reducedAABW production [Ramsayet al., 1994] followedby a bottomwatertemperaturedrop [Miller et al., 1987] precedingice growth [Kennett,
1985; Vincent et al., 1985], and an increase in corrosive
ment. Thereforeit is reasonableto expectthat many, if not all,
of the hiatusesrecordedbetween2000 and 3000 m paleodepth AABW production[Ramsayet al., 1994].
are due to sediment corrosion associated with a shallow CCD.
The middle Mioceneto late Pliocene(13-2 Ma) is characterHowever,it is still not clear what might havecausedthe shal- ized by frequent,temporallywell-definedhiatuseventsof 1 to
low water hiatusesin the early Paleocene.
2 m.y. duration that correlate with NH3 to NH8 events of
The 6 m.y. long hiatuscenteredaround42 Ma is recorded Keller and Barron [1987]. These are mainly recordedin shalmainlyin shallo• andintermediate
watersediments.
Isotopic low water, while deepwater hiatusesshowa plateau.
eviden•:e
[Browning
et al., 1996]setsat thistimethebeginThe late Plioceneto Recentpart of the hiatuscurve showsa
ning of the development of the Antarctic ice cap. It is rapid drop in numberand frequencyof hiatusesthat inversely
hypothesizedhere that increaseddeep water circulationand correlateswith the cooling indicated by the benthic oxygen
corrosionassociatedwith global cooling could have caused isotopes.This could be causedby several factors, including
widespread hiatuses in deep-sea sedimentsat this time. the betterrecoveryof youngersedimentsand thereforea lower
However, more detailedcomparisons
with deepwater circula- chanceof recordingartificial hiatuses.Alternatively, this can
tion recordsis necessaryto confirmthis hypothesis.
indicate that sediment erosion and corrosionis time depenThe Oligocene-Miocene
boundary(25-24 Ma) is markedby dent and thus that there has been insufficient time to create
a peak in intermediateand deepwaterhiatusesand a minimum hiatusesin the youngestsections.However, this smoothdrop
can also be an artefact of the time •interval chosen for this
in shallow water hiatuses. This interval is characterizedby
increasedbottom water circulationfollowing the opening of analysis, which masks the high-frequency cycles of
the Drake Passage[Barkerand Burrell, 1982;Tucholkeet al., Quaternaryglacio-eustaticsealevel change[e.g., Raytooet al.,
1976]. This suggeststhat the shallowwater and deep water 1989] possibly characterized by short (<0.5 m.y.) hiatuses,
systemswere decoupled.
not recordedin this study. Higher-resolutionstudiesare thus
Short and frequent hiatuses characterize the Neogene neededto explain this pattern.
(Figure2c). In the early Miocenea hiatuseventis recognized
between21 and 19 Ma, followed by two shorterhiatusevents 5. Conclusions
and Future
Studies
between18 and 17 Ma. Thesecorrespond
to the NHla andNH 1
The geographicdistributionof hiatusesin deep-seasediments(Figure 1) showsthat they are widespreadboth on continental shelvesand in deep-seabasinsbut that they are more
100
................................
a
common at high latitudes and on continental margins.
80
Hiatuses in Paleogenesectionsare few but several million
60
yearslong. Neogenesedimentsare characterized
by frequent,
short(maximumof 2 m.y. long) hiatuses.It is apparentfrom
this study that various modesof depth distributionof hiatusesexist. I suggestthat these different modesare linked to
differentcauses.Previousworks have mainly concentrated
on
the effects of cooling, deep water production,dissolution,
and/orerosionfor the formationof hiatuses.This studyrepre-
40
20
I
I
I
,
',
10u' .... !'.... ' ..................................................
,
,...
I
:I
,.
,
I
1....
.
i
,...
.;
.
....
sents a comprehensive,yet preliminary, overview of hiatus
frequencyin deep-seasediments.Future studieswill attempt
to determine the geographicdistributionof hiatuseswithin
ocean basins(e.g., latitudinal distributionof hiatusesversus
I
1ool
....r..........II........
I,.........'l.......................
'I.....•"'•
•l I
deeper
than
3000
m, I I ½
latitudinal
distribution
of
DSDP
and
ODP
holes
in the
databaseand western versus easternmarginsto identify the
temporal evolution of oceanic gyre circulation) and to compare them to detailed recordsof deep water circulation[e.g.,
Wright and Miller, 1993]. The depth distributionof hiatuses
in mid-oceanand aseismicridge sitesversuscontinentalshelf
and slope sites must be also analyzedseparately.These areas
Age in Ma
shouldbe affecteddifferentlyby sea level changes.
Figure 3. The lines with symbolsrepresentthe frequencyof hiatuses
Finally, I plan to assemblea curve of hiatusesoccurringin
recordedat variouspalcodepthintervals:(a) shallowerthan2000 m, (b)
deep water (>2,000 m) carbonate-richsediments.This hiatus
between2000 and 3000 m, and (c) deeperthan 3000 m. The continuous
curve could potentiallyrepresenta more detailedupdateof
lines representthe percentageof sectionsin the Neptunedatabasein
the CenozoicCCD curve of van Andel [1975].
that intervalof paleo-waterdepth.
•Ul
•!
I
I
'
I
I
,
[
!
!
182
SPENCER-CERVATO:DEPTH DISTRIBUTION OF CENOZOIC HIATUSES
Acknowledgements. I would like to thank D. B. Lazarus,H. R.
Thierstein,J.P. Beckmann,M. Biolzi, H. Hilbrecht, and K. von Salis
Burckle,J. OggandJ. D. Wrightwereveryprofitable.
I amgratefulto
D. F. Bellmap,D. B. Lazarus,D. A. Spencer,
J. D. Wright,R. Carter,D.
Perch-Nielsen
for theircontribution
to theNeptunedatabase
project.C.
Pak,andan anonymous
reviewerfor criticalreadingof themanuscript.
Nigrini andA. Sanfilippokindlyprovidedme with theirunpublished Their commentsand the suggestionsof M. Delaney have greatly
revised Paleogeneradiolarian biozonation.K. Miller kindly made improvedthe manuscript.
This studywasfundedby the SwissNational
availablethe isotopicdata from Miller et al. [1987] calibratedto the
ScienceFoundation
project20-40554.94.
Berggrenet al. [1995b] timescale.Discussions
with D. F. Belknap,L.
References
Aubry,M.P., Sequence
stratigraphy:
Eustasyor
tectonic imprint? J. Geophys.Res., 96,
southernlatitudes,Micropaleontology,30,
319-342, 1984.
Haq, B.U., J. Hardenbol,
and P.R. Vail,
Aubry,M.P., Fromchronology
to stratigraphy: Chronologyof fluctuatingsea levels since
the Triassic (250 million years ago to
Interpretingthe Lower andMiddle Eocene
present),Science,235, 1156-1167, 1987.
stratigraphic
recordin the AtlanticOcean,
in Geochronology,
TimeScalesand Global Harwood, D.M., and T. Maruyama, Middle
6641-6679, 1991.
Stratigraphic Correlation: •t Unified
Temporal Frameworkfor an Historical
Geology,editedby W.A. Berggren,D.V.
Kent, andJ. Hardenbol,SEPM Spec.Publ.,
54, 213-274, 1995.
Baldauf, J.G., and J.A. Barron, Diatom
Eocene
to
Pleistocene
diatom
biostratigraphy of Southern Ocean
sedimentsfrom the KerguelenPlateau,Leg
120, edited by S.W. Wise, Jr. et al., Proc.
OceanDrill. ProgramSci.Results,120, 683734, 1992.
Waxing(andwaning•lyricalon hiatuses:
Eocene-Quaternary
Indian Ocean hiatuses
as proxy indicators of water mass
production,
Paleoceanography,
9, 857-877,
1994.
Raytoo,M.E., W.F. Ruddiman,J. Backman,
B.M. Clement, and D.G. Martinson,Late
Pliocenevariationin northern
hemisphere
ice sheetsand northAtlanticdeepwater
circulation,
Paleoceanography,
4, 413-446,
1989.
Sanfilippo,A., and C. Nigrini, Radiolarian
stratigraphy
acrossthe Oligocene/Miocene
biostratigraphy: Kerguelen Plateau and Keller, G., andJ.A. Barron,Paleoceanographic transition,Mar. Micropaleontol.,24, 239285, 1995.
implicationsof Miocene deep-seahiatuses,
Prydz Bay regionsof the SouthernOcean,
Sanfilippo,A., M.J. Westberg-Smith,
andW.R.
Geol. Soc.Am. Bull., 94, 590-613, 1983.
edited by J. Barron, et al., Proc. Ocean
Riedel, Cenozoic radiolaria, inPlankton
Drilling ProgramSci.Results,119, 547-598, Keller, G., and J.A. Barron, Palcodepth
1991.
Stratigraphy, edited by H.M. Bolli, J.B.
distributionof Neogenedeep-seahiatuses,
Saunders,and K. Perch-Nielsen,pp. 631Paleoceanography,
2, 697-713, 1987.
Barker,P.F., andJ. Burrell,The influenceupon
712, Cambridge Univ. Press,Cambridge,
Southern Ocean circulation, sedimentation, Keller, G., T. Herbert, R. Dorsey,S. d'Hondt,
1985.
M. Johnsson, and W.R. Chi, Global
and climate of the opening of the Drake
distribution of late Paleogene hiatuses, Sclater, J.G., L. Meinke, A. Bennett, and C.
Passage,in •tntarctic Geoscience,editedby
Murphy, The depthof the oceanthroughthe
Geology,15, 199-203, 1987.
C. Craddock, pp. 377-385, Univ. of
Neogene,in The MioceneOcean,editedby
Kennett, J.P., Miocene-early Plioceneoxygen
Wisconsin
Press,Madison,1982.
J.P. Kennett, Mem. Geol. Soc. Am., 163, 1and carbon isotopic stratigraphy in the
Barron, J.A., The late Cenozoicstratigraphic
19, 1985.
record and hiatuses of the northeast Pacific:
SouthwestPacific: DSDP Leg 90, Initial
Rep. Deep Sea Drill. Proj., 90, 1383-1411, Shaw, A.B., Time in Stratigraphy,365 pp.,
Resultsfrom the Deep Sea Drilling Project,
1985.
McGraw-Hill, New York, 1964.
in TheGeologyof North•tmerica,vol. N,The
Eastern Pacific Ocean and Hawaii, edited Lazarus,D.B., Age/depthplot andAge maker: Spencer-Cervato,C., H.R. Thierstein, D.B.
Lazarus,
and J.P. Beckmann, How
Age/depth modelling on the Macintosh
by E.L. Winterer,D.M. Hussong,and R.W.
synchronousare Neogenemarine plankton
.Decker, Geol, Soc. Am., Boulder Colorado,
seriesof computers,Geobyte,7, 7-13, 1992.
events? Paleoceanography, 9, 739-763,
Lazarus, D., C. Spencer-Cervato,M. Pikapp. 311-372, 1989.
1994.
Biolzi, J.P. Beckmann,K. von Salis, K., H.
Berger,W.H., Biogenousdeep-seasediments:
Hilbrecht• and H.R. Thiefstein, Revised Tucholke,B.E., C.D. Hollister,F.M. Weaver,
Fractionation
by deep-seacirculation,Geol.
and W.R. Vennum, Continental rise and
chronologyof NeogeneDSDP Holes from
Soc.•tm. Bull., 81, 1385-1402, 1970.
abyssalplain sedimentation
in the southeast
the World Ocean, Tech. Note 24, 312 pp.,
Berggren,W.A., F.J. Hilgen, C.C. Langerels,
Pacificbasin,Leg 35 Deep SeaDrilling
OceanDrill. Program,CollegeStation,Tex.,
D.V. Kent, J.D. Obradovich, I. Raffi, M.
1995.
Project,Initial Rep.Deep SeaDrill. Proj.,
Raytoo,andN.J. Shackleton,Late Neogene
35, 279-294, 1976.
chronology: New perspectivesin high- Mayer, L.A., T.H. Shipley,andE.L. Winterer,
Equatorial Pacific seismic reflectors as Vail, P.R., R.M. MitchurnJr., R.G. Todd,J.M.
resolutionstratigraphy,
Geol.Soc.•tm. Bull.,
Widmier, S. ThompsonIII, J.B. Sangree,
107, 1272-1287, 1995a.
indicators
of globaloceanographic
events,
J.N. Bubb, and W.G. Hatlelid, Seismic
Berggren,W.A., D.V. Kent, C.C. Swisher,and
Science,233, 761-764, 1986.
stratigraphy
andglobalsea-level
changes,
in
M.P. Aubry, A revised Cenozoic Miall, A.D., Stratigraphic
sequences
andtheir
Seismic Stratigraphy: Applications to
geochronologyand chronostratigraphy,
in
chronostratigraphic
correlation,
J. Sediment.
HydrocarbonExploration,editedby C.E.
Geochronology,Time Scales and Global
Petrol.,61, 497-505, 1991.
•t•tPG Mere., 26, 49-212, 1977.
Stratigraphic Correlations: A Unified Miller, K.G., R.G. Fairbanks, and G.S. vanPayton,
Andel, T.H., Mesozoic/Cenozoic calcite
Temporal Framework for an Historical
Mountain,Tertiaryoxygenisotopesynthesis,
compensation depth and the global
Geology, edited by W.A. Berggren,D.V.
sea level history, and continentalmargin
distributionof calcareoussediments,Earth
Kent, andJ. Hardenbol, SEPM Spec.Publ.,
erosion,Paleoceanography,
2, 1-19, 1987.
Planet.Sci. Lett., 26, 187-195, 1975.
54, 129-212, 1995b.
Miller, K.G., D.V. Kent, A.N. Brower, L.M.
Browning, J.V., K.G. Miller, and D.K. Pak,
Bybell, M.D. Feigenson,R.K. Olsson,and Vincent,E., J.S. KillingIcy,andW.H. Berger,
Miocene oxygen and carbon isotope
Global implications of lower to middle
R.Z. Poore, Eocene-Oligocene sea-level
stratigraphy
of the tropicalIndianOcean,in
Eocene sequenceboundarieson the New
changeson the New Jerseycoastalplain
TheMioceneOcean,editedby J.P.Kennett,
Jerseycoastalplain: The icehousecometh,
linked to the deep-searecord,Geol. Soc.
Mere. Geol. Soc.•tm., 163, 103-130, 1985.
Geology,24, 639-642, 1996.
Am. Bull., 102, 331-339, 1990.
J.D. and K.G. Miller, SouthernOcean
Caulet,J.P.,Radiolarians
fromthe Kerguelen Miller, K.G., G.S. Mountain, the Leg 150 Wright,
influences on late Eocene to Miocene
ShipboardParty and Membersof the New
Plateau,Leg 119,editedby J. Barronet al.,
deepwater circulation, in The •tntarctic
Proc. OceanDrill. ProgramSci. Results,
JerseyCoastalPlainDrillingProject,Drilling
Paleoenvironment:
A Perspective
on Global
119, 513-546, 1991.
and datingNew JerseyOligocene-Miocene
Change Part 2, Antarct. Res. Ser., vol. 60,
sequences:
Ice volume,globalsealevel and
deMenoeal,
P., J. Bloemendal,
andJ. King,A
editedby J.P.KennettandD.A. Wamke,pp.
rock-magneticrecord of monsoonaldust
Exxon records, Science, 271, 1092-1095,
1-25,AGU, Washington,
D.C., 1993.
1996.
depositionof the Arabian Sea:Evidencefor
a shiftin themodeof deposition
at 2.4 Ma, Moore, T.C., Jr, T.H. Van Andel, C. Sancetta,
C. Spencer-Cervato, Stable Isotope
Proc. OceanDrill. ProgramSci. Res.,117,
andN. Pisias,Cenozoichiatusesin pelagic
389-407, 1991.
sediments,
Micropaleontology,
24, 113-138, Laboratory, 5764 Sawyer Environmental
ResearchCenter,Universityof Maine, Orono,
1978.
Farrell,J.W.,andT.R. Janecek,
LateNeogene
04469-5764.
(e-mail:
paleoceanography
andpaleoclimatology
of Osborn, N.I., P.F. Ciesielski, and M.T. ME
Ledbetter,
Disconformities
and cinzia•maine.maine.eau)
thenortheast
IndianOcean(Site758),Proc.
OceanDrill. ProgramSci.Results,121,297paleoceanography
in the southeastIndian
355, 1991.
Ocean during the past 5.4 million years, (ReceivedJune25, 1997;
revisedNovember 19, 1997;
Geol. Soc. Am. Bull., 94, 1345-1358, 1983.
Fenner,J., Eocene-Oligocene
planktiediatom
stratigraphy
in thelow latitudes
andthehigh Ramsay,A.T.S., T.J.S. Sykes,and R.B. Kidd, acceptedNovember28, 1997.)