Ice sheet collapse following a prolonged period of stable sea level during the last interglacial

Michael J. O'Leary, Paul J. Hearty, William G. Thompson, Maureen E. Raymo, Jerry X. Mitrovica, Jody M. Webster

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Abstract

During the last interglacial period, 127-116 kyr ago, global mean sea level reached a peak of 5-9m above present-day sea level. However, the exact timing and magnitude of ice sheet collapse that contributed to the sea-level highstand is unclear. Here we explore this timing using stratigraphic and geomorphic mapping and uranium-series geochronology of fossil coral reefs and geophysical modelling of sea-level records from Western Australia. We show that between 127 and 119 kyr ago, eustatic sea level remained relatively stable at about 3-4 m above present sea level. However, stratigraphically younger fossil corals with U-series ages of 118.1±1.4 kyr are observed at elevations of up to 9.5 m above present mean sea level. Accounting for glacial isostatic adjustment and localized tectonics, we conclude that eustatic sea level rose to about 9 m above present at the end of the last interglacial. We suggest that in the last few thousand years of the interglacial, a critical ice sheet stability threshold was crossed, resulting in the catastrophic collapse of polar ice sheets and substantial sea-level rise.

Original languageEnglish
Pages (from-to)796-800
Number of pages5
JournalNature Geoscience
Volume6
Issue number9
DOIs
Publication statusPublished - 1 Sep 2013
Externally publishedYes

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O'Leary, M. J., Hearty, P. J., Thompson, W. G., Raymo, M. E., Mitrovica, J. X., & Webster, J. M. (2013). Ice sheet collapse following a prolonged period of stable sea level during the last interglacial. Nature Geoscience, 6(9), 796-800. https://doi.org/10.1038/ngeo1890