Antecedent control on active ice sheet retreat revealed by seafloor geomorphology, offshore Windmill Islands, Antarctica
Understanding past retreat of Antarctic ice margins provides valuable insight for predicting how ice sheets may respond to future environmental change. This study, based on high resolution multibeam bathymetry from the nearshore region of the Windmill Islands, East Antarctica, reveals a style of ret...
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ftcopernicus:oai:publications.copernicus.org:tcd92262 2023-05-15T13:31:40+02:00 Antecedent control on active ice sheet retreat revealed by seafloor geomorphology, offshore Windmill Islands, Antarctica Post, Alexandra L. Phillips, Emrys Carson, Christopher J. Smith, Jodie 2021-01-29 application/pdf https://doi.org/10.5194/tc-2021-8 https://tc.copernicus.org/preprints/tc-2021-8/ eng eng doi:10.5194/tc-2021-8 https://tc.copernicus.org/preprints/tc-2021-8/ eISSN: 1994-0424 Text 2021 ftcopernicus https://doi.org/10.5194/tc-2021-8 2021-02-01T17:21:47Z Understanding past retreat of Antarctic ice margins provides valuable insight for predicting how ice sheets may respond to future environmental change. This study, based on high resolution multibeam bathymetry from the nearshore region of the Windmill Islands, East Antarctica, reveals a style of retreat that has been rarely observed on the Antarctic margin. A suite of seafloor features record the final retreat stages of a relatively thin, and increasingly fractured tidewater glacier confined within narrow troughs and embayments, forming a suite of features more typical of warm-based ice, but occurring here in a region of cold-based ice with limited surface meltwater production. The pattern of moraines and crevasse squeeze ridges, reveals strong topographic and substrate control on the nature of ice sheet retreat. Topographic control is indicated by fine-scale variability in the orientation and distribution of glacial landforms, which show that the seabed topography influenced the shape of the ice margin, caused deflection of ice flow and led to the separation of flow downstream from topographic highs. The availability of water saturated marine sediments within the troughs and depressions also had a profound effect on the landform record, facilitating the construction of moraines and crevasse squeeze ridges within topographic lows, corresponding to areas of modern sediment accumulation. Surrounding areas of crystalline bedrock, by contrast, acted as <q>sticky spots</q> and lack a well-developed landform record. This seafloor glacial record emphasises the importance of understanding the bed topography and substrate when predicting the nature of ice margin retreat and provides new perspectives for understanding the stability of the East Antarctic margin. Text Antarc* Antarctic Antarctica East Antarctica Ice Sheet Tidewater Windmill Islands Copernicus Publications: E-Journals Antarctic East Antarctica The Antarctic Windmill Islands ENVELOPE(110.417,110.417,-66.350,-66.350) |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Understanding past retreat of Antarctic ice margins provides valuable insight for predicting how ice sheets may respond to future environmental change. This study, based on high resolution multibeam bathymetry from the nearshore region of the Windmill Islands, East Antarctica, reveals a style of retreat that has been rarely observed on the Antarctic margin. A suite of seafloor features record the final retreat stages of a relatively thin, and increasingly fractured tidewater glacier confined within narrow troughs and embayments, forming a suite of features more typical of warm-based ice, but occurring here in a region of cold-based ice with limited surface meltwater production. The pattern of moraines and crevasse squeeze ridges, reveals strong topographic and substrate control on the nature of ice sheet retreat. Topographic control is indicated by fine-scale variability in the orientation and distribution of glacial landforms, which show that the seabed topography influenced the shape of the ice margin, caused deflection of ice flow and led to the separation of flow downstream from topographic highs. The availability of water saturated marine sediments within the troughs and depressions also had a profound effect on the landform record, facilitating the construction of moraines and crevasse squeeze ridges within topographic lows, corresponding to areas of modern sediment accumulation. Surrounding areas of crystalline bedrock, by contrast, acted as <q>sticky spots</q> and lack a well-developed landform record. This seafloor glacial record emphasises the importance of understanding the bed topography and substrate when predicting the nature of ice margin retreat and provides new perspectives for understanding the stability of the East Antarctic margin. |
format |
Text |
author |
Post, Alexandra L. Phillips, Emrys Carson, Christopher J. Smith, Jodie |
spellingShingle |
Post, Alexandra L. Phillips, Emrys Carson, Christopher J. Smith, Jodie Antecedent control on active ice sheet retreat revealed by seafloor geomorphology, offshore Windmill Islands, Antarctica |
author_facet |
Post, Alexandra L. Phillips, Emrys Carson, Christopher J. Smith, Jodie |
author_sort |
Post, Alexandra L. |
title |
Antecedent control on active ice sheet retreat revealed by seafloor geomorphology, offshore Windmill Islands, Antarctica |
title_short |
Antecedent control on active ice sheet retreat revealed by seafloor geomorphology, offshore Windmill Islands, Antarctica |
title_full |
Antecedent control on active ice sheet retreat revealed by seafloor geomorphology, offshore Windmill Islands, Antarctica |
title_fullStr |
Antecedent control on active ice sheet retreat revealed by seafloor geomorphology, offshore Windmill Islands, Antarctica |
title_full_unstemmed |
Antecedent control on active ice sheet retreat revealed by seafloor geomorphology, offshore Windmill Islands, Antarctica |
title_sort |
antecedent control on active ice sheet retreat revealed by seafloor geomorphology, offshore windmill islands, antarctica |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-2021-8 https://tc.copernicus.org/preprints/tc-2021-8/ |
long_lat |
ENVELOPE(110.417,110.417,-66.350,-66.350) |
geographic |
Antarctic East Antarctica The Antarctic Windmill Islands |
geographic_facet |
Antarctic East Antarctica The Antarctic Windmill Islands |
genre |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet Tidewater Windmill Islands |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet Tidewater Windmill Islands |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-2021-8 https://tc.copernicus.org/preprints/tc-2021-8/ |
op_doi |
https://doi.org/10.5194/tc-2021-8 |
_version_ |
1766019977043771392 |