Thickness of the divide and flank of the West Antarctic Ice Sheet through the last deglaciation
We report cosmogenic-nuclide measurements from two isolated groups of nunataks in West Antarctica: the Pirrit Hills, located midway between the grounding line and the divide in the Weddell Sea sector, and the Whitmore Mountains, located along the Ross–Weddell divide. At the Pirrit Hills, evidence of...
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ftcopernicus:oai:publications.copernicus.org:tc76632 2023-05-15T13:55:28+02:00 Thickness of the divide and flank of the West Antarctic Ice Sheet through the last deglaciation Spector, Perry Stone, John Goehring, Brent 2019-11-20 application/pdf https://doi.org/10.5194/tc-13-3061-2019 https://tc.copernicus.org/articles/13/3061/2019/ eng eng doi:10.5194/tc-13-3061-2019 https://tc.copernicus.org/articles/13/3061/2019/ eISSN: 1994-0424 Text 2019 ftcopernicus https://doi.org/10.5194/tc-13-3061-2019 2020-07-20T16:22:33Z We report cosmogenic-nuclide measurements from two isolated groups of nunataks in West Antarctica: the Pirrit Hills, located midway between the grounding line and the divide in the Weddell Sea sector, and the Whitmore Mountains, located along the Ross–Weddell divide. At the Pirrit Hills, evidence of glacial-stage ice cover extends ∼320 m above the present ice surface. Subsequent thinning mostly occurred after ∼14 kyr BP, and modern ice levels were established some time after ∼4 kyr BP. We infer that, like at other flank sites, these changes were primarily controlled by the position of the grounding line downstream. At the Whitmore Mountains, cosmogenic 14 C concentrations in bedrock surfaces demonstrate that ice there was no more than ∼190 m thicker than present during the past ∼30 kyr. Combined with other constraints from West Antarctica, the 14 C data imply that the divide was thicker than present for a period of less than ∼8 kyr within the past ∼15 kyr. These results are consistent with the hypothesis that the divide initially thickened due to the deglacial rise in snowfall and subsequently thinned in response to retreat of the ice-sheet margin. We use these data to evaluate several recently published ice-sheet models at the Pirrit Hills and Whitmore Mountains. Most of the models we consider do not match the observed timing and/or magnitude of thickness change at these sites. However, one model performs relatively well at both sites, which may, in part, be due to the fact that it was calibrated with geological observations of ice-thickness change from other sites in Antarctica. Text Antarc* Antarctic Antarctica Ice Sheet Weddell Sea West Antarctica Copernicus Publications: E-Journals Antarctic Weddell Sea West Antarctica West Antarctic Ice Sheet Weddell Whitmore Mountains ENVELOPE(-104.000,-104.000,-82.500,-82.500) Pirrit Hills ENVELOPE(-85.350,-85.350,-81.283,-81.283) The Cryosphere 13 11 3061 3075 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
We report cosmogenic-nuclide measurements from two isolated groups of nunataks in West Antarctica: the Pirrit Hills, located midway between the grounding line and the divide in the Weddell Sea sector, and the Whitmore Mountains, located along the Ross–Weddell divide. At the Pirrit Hills, evidence of glacial-stage ice cover extends ∼320 m above the present ice surface. Subsequent thinning mostly occurred after ∼14 kyr BP, and modern ice levels were established some time after ∼4 kyr BP. We infer that, like at other flank sites, these changes were primarily controlled by the position of the grounding line downstream. At the Whitmore Mountains, cosmogenic 14 C concentrations in bedrock surfaces demonstrate that ice there was no more than ∼190 m thicker than present during the past ∼30 kyr. Combined with other constraints from West Antarctica, the 14 C data imply that the divide was thicker than present for a period of less than ∼8 kyr within the past ∼15 kyr. These results are consistent with the hypothesis that the divide initially thickened due to the deglacial rise in snowfall and subsequently thinned in response to retreat of the ice-sheet margin. We use these data to evaluate several recently published ice-sheet models at the Pirrit Hills and Whitmore Mountains. Most of the models we consider do not match the observed timing and/or magnitude of thickness change at these sites. However, one model performs relatively well at both sites, which may, in part, be due to the fact that it was calibrated with geological observations of ice-thickness change from other sites in Antarctica. |
format |
Text |
author |
Spector, Perry Stone, John Goehring, Brent |
spellingShingle |
Spector, Perry Stone, John Goehring, Brent Thickness of the divide and flank of the West Antarctic Ice Sheet through the last deglaciation |
author_facet |
Spector, Perry Stone, John Goehring, Brent |
author_sort |
Spector, Perry |
title |
Thickness of the divide and flank of the West Antarctic Ice Sheet through the last deglaciation |
title_short |
Thickness of the divide and flank of the West Antarctic Ice Sheet through the last deglaciation |
title_full |
Thickness of the divide and flank of the West Antarctic Ice Sheet through the last deglaciation |
title_fullStr |
Thickness of the divide and flank of the West Antarctic Ice Sheet through the last deglaciation |
title_full_unstemmed |
Thickness of the divide and flank of the West Antarctic Ice Sheet through the last deglaciation |
title_sort |
thickness of the divide and flank of the west antarctic ice sheet through the last deglaciation |
publishDate |
2019 |
url |
https://doi.org/10.5194/tc-13-3061-2019 https://tc.copernicus.org/articles/13/3061/2019/ |
long_lat |
ENVELOPE(-104.000,-104.000,-82.500,-82.500) ENVELOPE(-85.350,-85.350,-81.283,-81.283) |
geographic |
Antarctic Weddell Sea West Antarctica West Antarctic Ice Sheet Weddell Whitmore Mountains Pirrit Hills |
geographic_facet |
Antarctic Weddell Sea West Antarctica West Antarctic Ice Sheet Weddell Whitmore Mountains Pirrit Hills |
genre |
Antarc* Antarctic Antarctica Ice Sheet Weddell Sea West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Weddell Sea West Antarctica |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-13-3061-2019 https://tc.copernicus.org/articles/13/3061/2019/ |
op_doi |
https://doi.org/10.5194/tc-13-3061-2019 |
container_title |
The Cryosphere |
container_volume |
13 |
container_issue |
11 |
container_start_page |
3061 |
op_container_end_page |
3075 |
_version_ |
1766262105849200640 |