Retreat of the West Antarctic Ice Sheet from the Western Amundsen Sea Shelf at a Pre- or Early LGM Stage
Recent palaeoglaciological studies on the West Antarctic shelf have mainly focused on the wide embayments of the Ross and Amundsen seas in order to reconstruct the extent and subsequent retreat of the West Antarctic Ice Sheet (WAIS) since the Last Glacial Maximum (LGM). However, the narrower shelf s...
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Digital Commons @ University of South Florida
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Online Access: | https://digitalcommons.usf.edu/msc_facpub/1550 https://doi.org/10.1016/j.quascirev.2014.02.017 |
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ftunisfloridatam:oai:digitalcommons.usf.edu:msc_facpub-2560 2023-05-15T13:24:01+02:00 Retreat of the West Antarctic Ice Sheet from the Western Amundsen Sea Shelf at a Pre- or Early LGM Stage Klages, J. P. Kuhn, G. Hillenbrand, C.-D. Graham, A. G. C. Smith, J. A. Larter, R. D. Gohl, K. Wacker, L. 2014-01-01T08:00:00Z https://digitalcommons.usf.edu/msc_facpub/1550 https://doi.org/10.1016/j.quascirev.2014.02.017 unknown Digital Commons @ University of South Florida https://digitalcommons.usf.edu/msc_facpub/1550 https://doi.org/10.1016/j.quascirev.2014.02.017 Marine Science Faculty Publications Last Glacial Maximum West Antarctic Ice Sheet Glacial retreat LGM extent Sea-level rise Grounding-zone wedge Getz Ice Shelf Amundsen Sea Deglaciation Life Sciences article 2014 ftunisfloridatam https://doi.org/10.1016/j.quascirev.2014.02.017 2022-01-20T18:39:16Z Recent palaeoglaciological studies on the West Antarctic shelf have mainly focused on the wide embayments of the Ross and Amundsen seas in order to reconstruct the extent and subsequent retreat of the West Antarctic Ice Sheet (WAIS) since the Last Glacial Maximum (LGM). However, the narrower shelf sectors between these two major embayments have remained largely unstudied in previous geological investigations despite them covering extensive areas of the West Antarctic shelf. Here, we present the first systematic marine geological and geophysical survey of a shelf sector offshore from the Hobbs Coast. It is dominated by a large grounding zone wedge (GZW), which fills the base of a palaeo-ice stream trough on the inner shelf and marks a phase of stabilization of the grounding line during general WAIS retreat following the last maximum ice-sheet extent in this particular area (referred to as the Local Last Glacial Maximum, ‘LLGM’). Reliable age determination on calcareous microfossils from the infill of a subglacial meltwater channel eroded into the GZW reveals that grounded ice had retreated landward of the GZW before ∼20.88 cal. ka BP, with deglaciation of the innermost shelf occurring prior to ∼12.97 cal. ka BP. Geophysical sub-bottom information from the inner-, mid- and outer shelf indicates grounded ice extended to the shelf edge prior to the formation of the GZW. Assuming the wedge was deposited during deglaciation, we infer the timing of maximum grounded ice extent occurred before ∼20.88 cal. ka BP. This could suggest that the WAIS retreat from the outer shelf was already underway during or even prior to the global LGM (∼23–19 cal. ka BP). Our new findings give insights into the regional deglacial behaviour of this understudied part of the West Antarctic shelf and at the same time support early deglaciation ages recently presented for adjacent drainage sectors of the WAIS. If correct, these findings contrast with the hypothesis that initial deglaciation of Antarctic Ice Sheets occurred synchronously at ∼19 cal. ka BP. Article in Journal/Newspaper Amundsen Sea Antarc* Antarctic Getz Ice Shelf Hobbs coast Ice Sheet Ice Shelf Digital Commons University of South Florida (USF) Antarctic Amundsen Sea West Antarctic Ice Sheet Hobbs ENVELOPE(-57.500,-57.500,-64.300,-64.300) Getz ENVELOPE(-145.217,-145.217,-76.550,-76.550) Getz Ice Shelf ENVELOPE(-126.500,-126.500,-74.250,-74.250) Hobbs Coast ENVELOPE(-136.000,-136.000,-75.500,-75.500) Quaternary Science Reviews 91 1 15 |
institution |
Open Polar |
collection |
Digital Commons University of South Florida (USF) |
op_collection_id |
ftunisfloridatam |
language |
unknown |
topic |
Last Glacial Maximum West Antarctic Ice Sheet Glacial retreat LGM extent Sea-level rise Grounding-zone wedge Getz Ice Shelf Amundsen Sea Deglaciation Life Sciences |
spellingShingle |
Last Glacial Maximum West Antarctic Ice Sheet Glacial retreat LGM extent Sea-level rise Grounding-zone wedge Getz Ice Shelf Amundsen Sea Deglaciation Life Sciences Klages, J. P. Kuhn, G. Hillenbrand, C.-D. Graham, A. G. C. Smith, J. A. Larter, R. D. Gohl, K. Wacker, L. Retreat of the West Antarctic Ice Sheet from the Western Amundsen Sea Shelf at a Pre- or Early LGM Stage |
topic_facet |
Last Glacial Maximum West Antarctic Ice Sheet Glacial retreat LGM extent Sea-level rise Grounding-zone wedge Getz Ice Shelf Amundsen Sea Deglaciation Life Sciences |
description |
Recent palaeoglaciological studies on the West Antarctic shelf have mainly focused on the wide embayments of the Ross and Amundsen seas in order to reconstruct the extent and subsequent retreat of the West Antarctic Ice Sheet (WAIS) since the Last Glacial Maximum (LGM). However, the narrower shelf sectors between these two major embayments have remained largely unstudied in previous geological investigations despite them covering extensive areas of the West Antarctic shelf. Here, we present the first systematic marine geological and geophysical survey of a shelf sector offshore from the Hobbs Coast. It is dominated by a large grounding zone wedge (GZW), which fills the base of a palaeo-ice stream trough on the inner shelf and marks a phase of stabilization of the grounding line during general WAIS retreat following the last maximum ice-sheet extent in this particular area (referred to as the Local Last Glacial Maximum, ‘LLGM’). Reliable age determination on calcareous microfossils from the infill of a subglacial meltwater channel eroded into the GZW reveals that grounded ice had retreated landward of the GZW before ∼20.88 cal. ka BP, with deglaciation of the innermost shelf occurring prior to ∼12.97 cal. ka BP. Geophysical sub-bottom information from the inner-, mid- and outer shelf indicates grounded ice extended to the shelf edge prior to the formation of the GZW. Assuming the wedge was deposited during deglaciation, we infer the timing of maximum grounded ice extent occurred before ∼20.88 cal. ka BP. This could suggest that the WAIS retreat from the outer shelf was already underway during or even prior to the global LGM (∼23–19 cal. ka BP). Our new findings give insights into the regional deglacial behaviour of this understudied part of the West Antarctic shelf and at the same time support early deglaciation ages recently presented for adjacent drainage sectors of the WAIS. If correct, these findings contrast with the hypothesis that initial deglaciation of Antarctic Ice Sheets occurred synchronously at ∼19 cal. ka BP. |
format |
Article in Journal/Newspaper |
author |
Klages, J. P. Kuhn, G. Hillenbrand, C.-D. Graham, A. G. C. Smith, J. A. Larter, R. D. Gohl, K. Wacker, L. |
author_facet |
Klages, J. P. Kuhn, G. Hillenbrand, C.-D. Graham, A. G. C. Smith, J. A. Larter, R. D. Gohl, K. Wacker, L. |
author_sort |
Klages, J. P. |
title |
Retreat of the West Antarctic Ice Sheet from the Western Amundsen Sea Shelf at a Pre- or Early LGM Stage |
title_short |
Retreat of the West Antarctic Ice Sheet from the Western Amundsen Sea Shelf at a Pre- or Early LGM Stage |
title_full |
Retreat of the West Antarctic Ice Sheet from the Western Amundsen Sea Shelf at a Pre- or Early LGM Stage |
title_fullStr |
Retreat of the West Antarctic Ice Sheet from the Western Amundsen Sea Shelf at a Pre- or Early LGM Stage |
title_full_unstemmed |
Retreat of the West Antarctic Ice Sheet from the Western Amundsen Sea Shelf at a Pre- or Early LGM Stage |
title_sort |
retreat of the west antarctic ice sheet from the western amundsen sea shelf at a pre- or early lgm stage |
publisher |
Digital Commons @ University of South Florida |
publishDate |
2014 |
url |
https://digitalcommons.usf.edu/msc_facpub/1550 https://doi.org/10.1016/j.quascirev.2014.02.017 |
long_lat |
ENVELOPE(-57.500,-57.500,-64.300,-64.300) ENVELOPE(-145.217,-145.217,-76.550,-76.550) ENVELOPE(-126.500,-126.500,-74.250,-74.250) ENVELOPE(-136.000,-136.000,-75.500,-75.500) |
geographic |
Antarctic Amundsen Sea West Antarctic Ice Sheet Hobbs Getz Getz Ice Shelf Hobbs Coast |
geographic_facet |
Antarctic Amundsen Sea West Antarctic Ice Sheet Hobbs Getz Getz Ice Shelf Hobbs Coast |
genre |
Amundsen Sea Antarc* Antarctic Getz Ice Shelf Hobbs coast Ice Sheet Ice Shelf |
genre_facet |
Amundsen Sea Antarc* Antarctic Getz Ice Shelf Hobbs coast Ice Sheet Ice Shelf |
op_source |
Marine Science Faculty Publications |
op_relation |
https://digitalcommons.usf.edu/msc_facpub/1550 https://doi.org/10.1016/j.quascirev.2014.02.017 |
op_doi |
https://doi.org/10.1016/j.quascirev.2014.02.017 |
container_title |
Quaternary Science Reviews |
container_volume |
91 |
container_start_page |
1 |
op_container_end_page |
15 |
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1766376967360217088 |