Penultimate deglacial sea level timing from U/Th dating of Tahitian corals Alex L. Thomas, Gideon M. Henderson, Pierre Deschamps, Yusuke Yokoyama, Andrew.

Penultimate deglacial sea level timing from U/Th dating

of Tahitian corals

Alex L. Thomas, Gideon M. Henderson, Pierre Deschamps, Yusuke Yokoyama, Andrew J. Mason, Edouard Bard, Bruno Hamelin, Nicolas Durand, and Gilbert Camoin

Outline

• TII Timing• IODP Expedition 310 “Tahiti Sea

Level”• My Results

Testing Milankovich’s Hypothesis…

LGM 21 kaNow 0 kaICE-5G Peltier 2004

…with Absolute Chronology

Broecker & van Donk 1970

12 ka

Controversy Surrounding the Timing of Termination II

• Direct U/Th dating of marine sediments.

• Timing of TII too early to have same phasing as TI with respect to NHI.

• Dating 18O Terminations in speleothems is not sea level

• Highstand coral ages also constrain timing.

Henderson & Slowey 2002

Thompson & Goldstein

2006 Open system

corrected coral ages

128 ka

100 150Age ka

De

pth

mb

sl

1018 S

17.75 S

150 W149 W

FaaaM0019M0020

TiareiM0009

MaraaM0005

18°S

149°

W

Tahiti

IODP Expedition 310

• Objectives of Exp 310 to constrain postglacial: sea level rise; SSTs; and reef geometry response.

• Of 37 holes, 28 penetrated Pre-LGM material

The Most Recent Deglaciation

IODP EXP325 GBREC

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Deschamps et al. in prep

MWP-1ABarbadosStanford et al 2006





Is there a dipstick for sea level?

Milne & Mitrovica 2008 QSR

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Age (ka)

)lsbm(noitaveledetcurtsnoceR

Stein 1993, Esat 1999

Stirling 1995, 1998

Eisenhauer 1996

Szabo 1994

Thompson 2003

Bard 1990, Gallup 2002

Huon Peninsula

W.Australia

Barbados

Hawaii

Termination II coral data

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Age (ka)



Stirling 1995, 1998

Eisenhauer 1996

Szabo 1994

Thompson 2003


Huon Peninsula

W.Australia

Barbados

Hawaii

Robust U/Th ages

U/Th alteration

This Study

New data from IODP Exp 310

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Age (ka)


731

latest time by whichsea level rose to 85 mbsl


Stirling 1995, 1998

Eisenhauer 1996

Szabo 1994

Thompson 2003


Huon Peninsula

W.Australia

Barbados

Hawaii

Robust U/Th ages

U/Th alteration

This Study

Timing constraint

Fit timing of continuous records to coral chronology

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731

241


start of deglaciation?


Stirling 1995, 1998

Eisenhauer 1996

Szabo 1994

Thompson 2003


Huon Peninsula

W.Australia

Barbados

Hawaii

Bintanja 2005+4.5 ka

Robust U/Th ages

U/Th alteration

This Study

Continuous sea levelwith adjusted timing

An Alternative Sea Level Curve

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731

241




Stirling 1995, 1998

Eisenhauer 1996

Szabo 1994

Thompson 2003


Huon Peninsula

W.Australia

Barbados

Hawaii


Siddall 2006+2.5 ka

Robust U/Th ages

U/Th alteration

This Study


Insolation Forcing of Sea Level Rise

Fuji 18O

N. Atlantic 18O

Northern H Summer

Southern H Summer

Timing of sea level rise is not out of phase with CO2

CO2 Fuji

CO2 Vostok

18Oatm Vostok

All Ice-core data are on the Dome Fuji timescale of Kawamura et al 2007

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125 130 135 140 145 150 155

130

110

90

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Age (ka)


731

241




Stirling 1995, 1998

Eisenhauer 1996

Szabo 1994

Thompson 2003


Huon Peninsula

W.Australia

Barbados

Hawaii


Siddall 2006+2.5 ka

Robust U/Th ages

U/Th alteration

This Study


Can we get more from the corals?

Drowning of Reefs

IODP EXP325 GBREC



Deschamps et al. in prep





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90

70

50

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125 130 135 140 145 150 155

130

110

90

70

50

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Age (ka)


731

241




Stirling 1995, 1998

Eisenhauer 1996

Szabo 1994

Thompson 2003


Huon Peninsula

W.Australia

Barbados

Hawaii


Siddall 2006+2.5 ka

Robust U/Th ages

U/Th alteration

Paleo-depth estimate

This Study


Paleodepths suggest a fall in sea level during the

deglaciation

Widespread evidence of millennial–scale lowstand

Esat et al 1999 (PNG)

Siddall et al 2006 (Red Sea)

Andrews et al 2007 (Gulf of Corinth)

Conclusions

• Expedition 310 “Tahiti Sea Level” has been a great success, for drilling operations and for science

• Sea level rise at the penultimate deglaciation was early with respect to phasing with NHI seen at TI

• Sea level, and CO2, rise are not out of phase.

• There is a substantial fall in global sea level during the penultimate deglaciation, indicating a readvance of ice sheets during a period of CO2 rise and warming.

Shameless Self Promotion

Out now online, and in print soon

[email protected]

Effect of GIA on Timing

Early Late

Initial rise starts synchronously

EarlyLate

Milne & Mitrovica 2008 QSR

Source of MWP-1A

Penultimate deglacial sea level timing from U/Th dating of Tahitian corals Alex L. Thomas, Gideon M. Henderson, Pierre Deschamps, Yusuke Yokoyama, Andrew.

Documents

ka slide

deglaciation slide

prep slide

qsr slide

timing constraint slide

timing of sea level

coral data slide

tahiti sea level