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Improvements from Bern 2008 on “The timing of Termination II: New constraints from Tahiti”

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Alexander L. Thomas1, Gideon M. Henderson1, Pierre Deschamps2, Yusuke Yokoyama3, Andrew J. Mason1, Edouard Bard2,4, Bruno Hamelin2, Nicolas Durand2, and Gilbert Camoin2

1Department of Earth Science, Parks Road, Oxford, OX1 3PR, United Kingdom, (alext@earth.ox.ac.uk)

2Europôle Méditerranéen de l’Arbois, CEREGE, UMR CNRS 6635, BP 80, F-13545 Aix-en-Provence Cedex 4,

3Department of Earth and Planetary Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan,

4Chaire d’évolution du climat et de l’océan, Collège de France, Europôle Méditerranéen de l’Arbois, F-13545 Aix-en-Provence Cedex 4.

 

            Following the August 2008 sea level workshop in Bern, a number of improvements to interpretation of coral U/Th data around the timing of Termination II have been made. Notably in our comparison of coral constraints to continuous d18O based sea level records, and to the assumptions we make about the deviation of relative sea level at Tahiti from ice volume equivalent sea level. Here we would like to thank the attendees of the Bern workshop for their constructive comments and present the updated story.

            The timing of sea-level change provides important constraints on the mechanisms driving Earth’s climate between glacial and interglacial states. Fossil corals constrain the timing of past sea level by their suitability for dating and their growth position close to sea level. The coral-derived age for the last deglaciation is consistent with climate change forced by Northern Hemisphere summer insolation (NHI), but the timing of the penultimate deglaciation is more controversial. We found, by means of uranium/thorium dating of fossil corals, that sea level during the penultimate deglaciation had risen to ~85 meters below the present sea level by 137,000 years ago, and that it fluctuated on a millennial time scale during deglaciation. This indicates that the penultimate deglaciation occurred earlier with respect to NHI than the last deglacial, beginning when NHI was at a minimum.

 

A. L. Thomas et al. Penultimate Deglacial Sea-Level Timing from U/Th Dating of Tahitian Corals. Science (23 April) 2009



Last updated: September 9, 2009
 


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