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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

Title:
Ice Sheet Collapse Following a Prolonged Period of Stable Sea Level during the Last Interglacial
Author(s):
O’Leary, Michael J.
Hearty, Paul J.
Thompson, William G.
Raymo, Maureen E.
Mitrovica, Jerry X.
Webster, Jody M.
Date:
Type:
Articles
Department:
Lamont-Doherty Earth Observatory
Volume:
6
Permanent URL:
Book/Journal Title:
Nature Geoscience
Abstract:
During the last interglacial period, 127–116 kyr ago, global mean sea level reached a peak of 5–9  m 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.
Subject(s):
Paleoclimate science
Chemical oceanography
Geomorphology
Publisher DOI:
http://dx.doi.org/10.1038/NGEO1890
Item views:
101
Metadata:
text | xml

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