Limited grounding-line advance onto the West Antarctic continental shelf in the easternmost Amundsen Sea Embayment during the last glacial period
Precise knowledge about the extent of the West Antarctic Ice Sheet (WAIS) at the Last Glacial Maximum (LGM; c. 26.5–19 cal. ka BP) is important in order to 1) improve paleo-ice sheet reconstructions, 2) provide a robust empirical framework for calibrating paleo-ice sheet models, and 3) locate potent...
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ftpubmed:oai:pubmedcentral.nih.gov:5526568 2023-05-15T13:23:41+02:00 Limited grounding-line advance onto the West Antarctic continental shelf in the easternmost Amundsen Sea Embayment during the last glacial period Klages, Johann P. Kuhn, Gerhard Hillenbrand, Claus-Dieter Smith, James A. Graham, Alastair G. C. Nitsche, Frank O. Frederichs, Thomas Jernas, Patrycja E. Gohl, Karsten Wacker, Lukas 2017-07-25 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5526568/ http://www.ncbi.nlm.nih.gov/pubmed/28742864 https://doi.org/10.1371/journal.pone.0181593 en eng Public Library of Science http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5526568/ http://www.ncbi.nlm.nih.gov/pubmed/28742864 http://dx.doi.org/10.1371/journal.pone.0181593 © 2017 Klages et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. CC-BY Research Article Text 2017 ftpubmed https://doi.org/10.1371/journal.pone.0181593 2017-08-13T00:08:03Z Precise knowledge about the extent of the West Antarctic Ice Sheet (WAIS) at the Last Glacial Maximum (LGM; c. 26.5–19 cal. ka BP) is important in order to 1) improve paleo-ice sheet reconstructions, 2) provide a robust empirical framework for calibrating paleo-ice sheet models, and 3) locate potential shelf refugia for Antarctic benthos during the last glacial period. However, reliable reconstructions are still lacking for many WAIS sectors, particularly for key areas on the outer continental shelf, where the LGM-ice sheet is assumed to have terminated. In many areas of the outer continental shelf around Antarctica, direct geological data for the presence or absence of grounded ice during the LGM is lacking because of post-LGM iceberg scouring. This also applies to most of the outer continental shelf in the Amundsen Sea. Here we present detailed marine geophysical and new geological data documenting a sequence of glaciomarine sediments up to ~12 m thick within the deep outer portion of Abbot Trough, a palaeo-ice stream trough on the outer shelf of the Amundsen Sea Embayment. The upper 2–3 meters of this sediment drape contain calcareous foraminifera of Holocene and (pre-)LGM age and, in combination with palaeomagnetic age constraints, indicate that continuous glaciomarine deposition persisted here since well before the LGM, possibly even since the last interglacial period. Our data therefore indicate that the LGM grounding line, whose exact location was previously uncertain, did not reach the shelf edge everywhere in the Amundsen Sea. The LGM grounding line position coincides with the crest of a distinct grounding-zone wedge ~100 km inland from the continental shelf edge. Thus, an area of ≥6000 km2 remained free of grounded ice through the last glacial cycle, requiring the LGM grounding line position to be re-located in this sector, and suggesting a new site at which Antarctic shelf benthos may have survived the last glacial period. Text Amundsen Sea Antarc* Antarctic Antarctica Ice Sheet Iceberg* PubMed Central (PMC) Amundsen Sea Antarctic West Antarctic Ice Sheet PLOS ONE 12 7 e0181593 |
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English |
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Research Article |
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Research Article Klages, Johann P. Kuhn, Gerhard Hillenbrand, Claus-Dieter Smith, James A. Graham, Alastair G. C. Nitsche, Frank O. Frederichs, Thomas Jernas, Patrycja E. Gohl, Karsten Wacker, Lukas Limited grounding-line advance onto the West Antarctic continental shelf in the easternmost Amundsen Sea Embayment during the last glacial period |
topic_facet |
Research Article |
description |
Precise knowledge about the extent of the West Antarctic Ice Sheet (WAIS) at the Last Glacial Maximum (LGM; c. 26.5–19 cal. ka BP) is important in order to 1) improve paleo-ice sheet reconstructions, 2) provide a robust empirical framework for calibrating paleo-ice sheet models, and 3) locate potential shelf refugia for Antarctic benthos during the last glacial period. However, reliable reconstructions are still lacking for many WAIS sectors, particularly for key areas on the outer continental shelf, where the LGM-ice sheet is assumed to have terminated. In many areas of the outer continental shelf around Antarctica, direct geological data for the presence or absence of grounded ice during the LGM is lacking because of post-LGM iceberg scouring. This also applies to most of the outer continental shelf in the Amundsen Sea. Here we present detailed marine geophysical and new geological data documenting a sequence of glaciomarine sediments up to ~12 m thick within the deep outer portion of Abbot Trough, a palaeo-ice stream trough on the outer shelf of the Amundsen Sea Embayment. The upper 2–3 meters of this sediment drape contain calcareous foraminifera of Holocene and (pre-)LGM age and, in combination with palaeomagnetic age constraints, indicate that continuous glaciomarine deposition persisted here since well before the LGM, possibly even since the last interglacial period. Our data therefore indicate that the LGM grounding line, whose exact location was previously uncertain, did not reach the shelf edge everywhere in the Amundsen Sea. The LGM grounding line position coincides with the crest of a distinct grounding-zone wedge ~100 km inland from the continental shelf edge. Thus, an area of ≥6000 km2 remained free of grounded ice through the last glacial cycle, requiring the LGM grounding line position to be re-located in this sector, and suggesting a new site at which Antarctic shelf benthos may have survived the last glacial period. |
format |
Text |
author |
Klages, Johann P. Kuhn, Gerhard Hillenbrand, Claus-Dieter Smith, James A. Graham, Alastair G. C. Nitsche, Frank O. Frederichs, Thomas Jernas, Patrycja E. Gohl, Karsten Wacker, Lukas |
author_facet |
Klages, Johann P. Kuhn, Gerhard Hillenbrand, Claus-Dieter Smith, James A. Graham, Alastair G. C. Nitsche, Frank O. Frederichs, Thomas Jernas, Patrycja E. Gohl, Karsten Wacker, Lukas |
author_sort |
Klages, Johann P. |
title |
Limited grounding-line advance onto the West Antarctic continental shelf in the easternmost Amundsen Sea Embayment during the last glacial period |
title_short |
Limited grounding-line advance onto the West Antarctic continental shelf in the easternmost Amundsen Sea Embayment during the last glacial period |
title_full |
Limited grounding-line advance onto the West Antarctic continental shelf in the easternmost Amundsen Sea Embayment during the last glacial period |
title_fullStr |
Limited grounding-line advance onto the West Antarctic continental shelf in the easternmost Amundsen Sea Embayment during the last glacial period |
title_full_unstemmed |
Limited grounding-line advance onto the West Antarctic continental shelf in the easternmost Amundsen Sea Embayment during the last glacial period |
title_sort |
limited grounding-line advance onto the west antarctic continental shelf in the easternmost amundsen sea embayment during the last glacial period |
publisher |
Public Library of Science |
publishDate |
2017 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5526568/ http://www.ncbi.nlm.nih.gov/pubmed/28742864 https://doi.org/10.1371/journal.pone.0181593 |
geographic |
Amundsen Sea Antarctic West Antarctic Ice Sheet |
geographic_facet |
Amundsen Sea Antarctic West Antarctic Ice Sheet |
genre |
Amundsen Sea Antarc* Antarctic Antarctica Ice Sheet Iceberg* |
genre_facet |
Amundsen Sea Antarc* Antarctic Antarctica Ice Sheet Iceberg* |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5526568/ http://www.ncbi.nlm.nih.gov/pubmed/28742864 http://dx.doi.org/10.1371/journal.pone.0181593 |
op_rights |
© 2017 Klages et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1371/journal.pone.0181593 |
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PLOS ONE |
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12 |
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7 |
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e0181593 |
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