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

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Presentation on theme: "Penultimate deglacial sea level timing from U/Th dating of Tahitian corals Alex L. Thomas, Gideon M. Henderson, Pierre Deschamps, Yusuke Yokoyama, Andrew."— Presentation transcript:

1 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

2 Outline TII Timing IODP Expedition 310 Tahiti Sea Level My Results

3 Testing Milankovichs Hypothesis… LGM 21 kaNow 0 ka ICE-5G Peltier 2004

4 …with Absolute Chronology Broecker & van Donk ka

5 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 18 O 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 Age ka Depth mbsl

6 Faaa M0019 M0020 Tiarei M0009 Maraa M °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

7 The Most Recent Deglaciation IODP EXP325 GBREC Deschamps et al. in prep MWP-1A Barbados Stanford et al 2006

8 Is there a dipstick for sea level? Milne & Mitrovica 2008 QSR

9 Termination II coral data

10 New data from IODP Exp 310

11 Timing constraint

12 Fit timing of continuous records to coral chronology

13 An Alternative Sea Level Curve

14 Insolation Forcing of Sea Level Rise Fuji 18 O N. Atlantic 18 O Northern H Summer Southern H Summer

15 Timing of sea level rise is not out of phase with CO 2 CO2 Fuji CO2 Vostok 18 O atm Vostok All Ice-core data are on the Dome Fuji timescale of Kawamura et al 2007

16 Can we get more from the corals?

17 Drowning of Reefs IODP EXP325 GBREC Deschamps et al. in prep

18

19 Paleodepths suggest a fall in sea level during the deglaciation

20 Widespread evidence of millennial– scale lowstand Esat et al 1999 (PNG) Siddall et al 2006 (Red Sea) Andrews et al 2007 (Gulf of Corinth)

21 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 CO 2, 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 CO 2 rise and warming.

22 Shameless Self Promotion Out now online, and in print soon

23 Effect of GIA on Timing EarlyLate Initial rise starts synchronously Early Late Milne & Mitrovica 2008 QSR

24 Source of MWP-1A


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