Wang, Jiakai;
Tang, Zheng;
Wilson, David J;
Chang, Fengming;
Xiong, Zhifang;
Dongyong, Li;
Li, Tiegang;
(2022)
Ocean-forced instability of the West Antarctic Ice Sheet since the mid-Pleistocene.
Geochemistry, Geophysics, Geosystems
, 23
(9)
, Article e2022GC010470. 10.1029/2022gc010470.
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Abstract
Evidence on West Antarctic Ice Sheet (WAIS) instability through Pleistocene glacial/interglacial cycles can provide fundamental constraints on interactions between the climate system and cryosphere. To explore such ice sheet-ocean-climate processes on orbital timescales over the last ∼770 ka, we provide continuous records of iceberg-rafted debris (IRD) content and clay mineralogy, supported by detrital Sr-Nd isotopes from the pronounced IRD peaks, in gravity core ANT34/A2-10 from the Amundsen abyssal plain. The IRD record reveals interglacial WAIS instability since ∼770 ka, while comparison to the clay mineralogy record and published records of regional oceanic and atmospheric forcing suggests a temporal link with a strengthened Antarctic Circumpolar Current, enhanced deepwater ventilation, and poleward-shifted Southern Westerly Winds. In addition, the Sr-Nd isotope signature of the detrital sediments indicates a shift in provenance around Marine Isotope Stage (MIS) 16, potentially linked to regional oceanic circulation changes. We suggest that an expanded Ross Gyre was important for controlling iceberg trajectories and sediment transport to the site before MIS 16, whereas modern-like iceberg trajectories were established after MIS 16, probably related to a poleward shift of the Amundsen Sea Low after the end of the Mid-Pleistocene Transition. This reorganization of the ocean and atmospheric circulation was followed by an interval of enhanced WAIS variability during MIS 15 to 13, which was linked to strong orbital and ocean forcing. These insights into the role of ocean-atmosphere forcing on the past behaviour of the WAIS may improve our framework for understanding future changes in this region.
| Type: | Article |
|---|---|
| Title: | Ocean-forced instability of the West Antarctic Ice Sheet since the mid-Pleistocene |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1029/2022gc010470 |
| Publisher version: | https://doi.org/10.1029/2022gc010470 |
| Language: | English |
| Additional information: | Copyright © 2022. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Antarctica, WAIS instability, ocean forcing, iceberg-rafted debris, clay minerals, Sr-Nd isotopes, Pleistocene |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10154027 |
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