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Initiation and long-term instability of the East Antarctic Ice Sheet

Initiation and long-term instability of the East Antarctic Ice Sheet
Initiation and long-term instability of the East Antarctic Ice Sheet
Antarctica’s continental-scale ice sheets have evolved over the past 50 million years1,2,3,4. However, the dearth of ice-proximal geological records5,6,7,8 limits our understanding of past East Antarctic Ice Sheet (EAIS) behaviour and thus our ability to evaluate its response to ongoing environmental change. The EAIS is marine-terminating and grounded below sea level within the Aurora subglacial basin, indicating that this catchment, which drains ice to the Sabrina Coast, may be sensitive to climate perturbations9,10,11. Here we show, using marine geological and geophysical data from the continental shelf seaward of the Aurora subglacial basin, that marine-terminating glaciers existed at the Sabrina Coast by the early to middle Eocene epoch. This finding implies the existence of substantial ice volume in the Aurora subglacial basin before continental-scale ice sheets were established about 34 million years ago1,2,3,4. Subsequently, ice advanced across and retreated from the Sabrina Coast continental shelf at least 11 times during the Oligocene and Miocene epochs. Tunnel valleys12 associated with half of these glaciations indicate that a surface-meltwater-rich sub-polar glacial system existed under climate conditions similar to those anticipated with continued anthropogenic warming10,11. Cooling since the late Miocene13 resulted in an expanded polar EAIS and a limited glacial response to Pliocene warmth in the Aurora subglacial basin catchment14,15,16. Geological records from the Sabrina Coast shelf indicate that, in addition to ocean temperature, atmospheric temperature and surface-derived meltwater influenced East Antarctic ice mass balance under warmer-than-present climate conditions. Our results imply a dynamic EAIS response with continued anthropogenic warming and suggest that the EAIS contribution to future global sea-level projections10,11,15,17 may be under-estimated.
0028-0836
225-229
Gulick, Sean P. S.
2b9eb82d-31fe-4089-9c63-cd91b1c3c6bd
Shevenell, Amelia E.
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Montelli, Aleksandr
cd1473dc-9fce-424f-8bbd-71490a8433ac
Fernandez, Rodrigo
b6b3d26b-eb6b-4e3f-b5ef-99227f52b3b6
Smith, Catherine
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Warny, Sophie
346a99af-47d8-40ec-8cdc-5836a44d3b9b
Bohaty, Steven M.
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Sjunneskog, Charlotte
a4a03ace-8de6-496b-80ec-9d623635da9f
Leventer, Amy
ad12e829-b2e0-461e-973d-3dac7f4824db
Frederick, Bruce
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Blankenship, Donald D.
e7c273e4-0aab-4a3f-869b-54b78959233b
Gulick, Sean P. S.
2b9eb82d-31fe-4089-9c63-cd91b1c3c6bd
Shevenell, Amelia E.
647657ba-5b5b-42e3-b010-d0d0d5e119ba
Montelli, Aleksandr
cd1473dc-9fce-424f-8bbd-71490a8433ac
Fernandez, Rodrigo
b6b3d26b-eb6b-4e3f-b5ef-99227f52b3b6
Smith, Catherine
3aa04903-ea22-483d-8587-d789dd388f35
Warny, Sophie
346a99af-47d8-40ec-8cdc-5836a44d3b9b
Bohaty, Steven M.
af9dbe78-8b9f-44f2-ba1d-20795837d2d1
Sjunneskog, Charlotte
a4a03ace-8de6-496b-80ec-9d623635da9f
Leventer, Amy
ad12e829-b2e0-461e-973d-3dac7f4824db
Frederick, Bruce
23caa112-a8c6-431d-b784-5c7771f15203
Blankenship, Donald D.
e7c273e4-0aab-4a3f-869b-54b78959233b

Gulick, Sean P. S., Shevenell, Amelia E., Montelli, Aleksandr, Fernandez, Rodrigo, Smith, Catherine, Warny, Sophie, Bohaty, Steven M., Sjunneskog, Charlotte, Leventer, Amy, Frederick, Bruce and Blankenship, Donald D. (2017) Initiation and long-term instability of the East Antarctic Ice Sheet. Nature, 552 (7684), 225-229. (doi:10.1038/nature25026).

Record type: Article

Abstract

Antarctica’s continental-scale ice sheets have evolved over the past 50 million years1,2,3,4. However, the dearth of ice-proximal geological records5,6,7,8 limits our understanding of past East Antarctic Ice Sheet (EAIS) behaviour and thus our ability to evaluate its response to ongoing environmental change. The EAIS is marine-terminating and grounded below sea level within the Aurora subglacial basin, indicating that this catchment, which drains ice to the Sabrina Coast, may be sensitive to climate perturbations9,10,11. Here we show, using marine geological and geophysical data from the continental shelf seaward of the Aurora subglacial basin, that marine-terminating glaciers existed at the Sabrina Coast by the early to middle Eocene epoch. This finding implies the existence of substantial ice volume in the Aurora subglacial basin before continental-scale ice sheets were established about 34 million years ago1,2,3,4. Subsequently, ice advanced across and retreated from the Sabrina Coast continental shelf at least 11 times during the Oligocene and Miocene epochs. Tunnel valleys12 associated with half of these glaciations indicate that a surface-meltwater-rich sub-polar glacial system existed under climate conditions similar to those anticipated with continued anthropogenic warming10,11. Cooling since the late Miocene13 resulted in an expanded polar EAIS and a limited glacial response to Pliocene warmth in the Aurora subglacial basin catchment14,15,16. Geological records from the Sabrina Coast shelf indicate that, in addition to ocean temperature, atmospheric temperature and surface-derived meltwater influenced East Antarctic ice mass balance under warmer-than-present climate conditions. Our results imply a dynamic EAIS response with continued anthropogenic warming and suggest that the EAIS contribution to future global sea-level projections10,11,15,17 may be under-estimated.

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Accepted/In Press date: 6 November 2017
e-pub ahead of print date: 13 December 2017
Published date: 13 December 2017

Identifiers

Local EPrints ID: 417070
URI: http://eprints.soton.ac.uk/id/eprint/417070
ISSN: 0028-0836
PURE UUID: 3e671dce-d6fd-47a9-ae16-c85890ee2a69
ORCID for Steven M. Bohaty: ORCID iD orcid.org/0000-0002-1193-7398

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Date deposited: 18 Jan 2018 17:30
Last modified: 07 Oct 2020 01:53

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Contributors

Author: Sean P. S. Gulick
Author: Amelia E. Shevenell
Author: Aleksandr Montelli
Author: Rodrigo Fernandez
Author: Catherine Smith
Author: Sophie Warny
Author: Charlotte Sjunneskog
Author: Amy Leventer
Author: Bruce Frederick
Author: Donald D. Blankenship

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