Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica
The Ekström Ice Shelf is one of numerous small ice shelves that fringe the coastline of western Dronning Maud Land, East Antarctica. Reconstructions of past ice-sheet extent in this area are poorly constrained, due to a lack of geomorphological evidence. Here, we present a compilation of geophysical...
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ftleedsuniv:oai:eprints.whiterose.ac.uk:190057 2023-05-15T13:55:51+02:00 Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica Oetting, A Smith, EC Arndt, JE Dorschel, B Drews, R Ehlers, TA Gaedicke, C Hofstede, C Klages, JP Kuhn, G Lambrecht, A Läufer, A Mayer, C Tiedemann, R Wilhelms, F Eisen, O 2022-05-30 text https://eprints.whiterose.ac.uk/190057/ https://eprints.whiterose.ac.uk/190057/1/tc-16-2051-2022.pdf en eng Copernicus Publications https://eprints.whiterose.ac.uk/190057/1/tc-16-2051-2022.pdf Oetting, A, Smith, EC orcid.org/0000-0002-8672-8259 , Arndt, JE et al. (13 more authors) (2022) Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica. The Cryosphere, 16 (5). pp. 2051-2066. ISSN 1994-0424 cc_by_4 CC-BY Article NonPeerReviewed 2022 ftleedsuniv 2023-01-30T22:48:51Z The Ekström Ice Shelf is one of numerous small ice shelves that fringe the coastline of western Dronning Maud Land, East Antarctica. Reconstructions of past ice-sheet extent in this area are poorly constrained, due to a lack of geomorphological evidence. Here, we present a compilation of geophysical surveys in front of and beneath the Ekström Ice Shelf, to identify and interpret evidence of past ice-sheet flow, extent and retreat. The sea floor beneath the Ekström Ice Shelf is dominated by an incised trough, which extends from the modern-day grounding line onto the continental shelf. Our surveys show that mega-scale glacial lineations cover most of the mouth of this trough, terminating 11 km away from the continental shelf break, indicating the most recent minimal extent of grounded ice in this region. Beneath the front ∼30 km of the ice shelf measured from the ice shelf edge towards the inland direction, the sea floor is characterised by an acoustically transparent sedimentary unit, up to 45 m thick. This is likely composed of subglacial till, further corroborating the presence of past grounded ice cover. Further inland, the sea floor becomes rougher, interpreted as a transition from subglacial tills to a crystalline bedrock, corresponding to the outcrop of the volcanic Explora Wedge at the sea floor. Ice retreat in this region appears to have happened rapidly in the centre of the incised trough, evidenced by a lack of overprinting of the lineations at the trough mouth. At the margins of the trough uniformly spaced recessional moraines suggest ice retreated more gradually. We estimate the palaeo-ice thickness at the calving front around the Last Glacial Maximum to have been at least 305 to 320 m, based on the depth of iceberg ploughmarks within the trough and sea level reconstructions. Given the similarity of the numerous small ice shelves along the Dronning Maud Land coast, these findings are likely representative for other ice shelves in this region and provide essential boundary conditions for palaeo ... Article in Journal/Newspaper Antarc* Antarctica Dronning Maud Land East Antarctica Ice Sheet Ice Shelf Ice Shelves The Cryosphere White Rose Research Online (Universities of Leeds, Sheffield & York) Dronning Maud Land East Antarctica Ekström Ice Shelf ENVELOPE(-8.000,-8.000,-71.000,-71.000) |
institution |
Open Polar |
collection |
White Rose Research Online (Universities of Leeds, Sheffield & York) |
op_collection_id |
ftleedsuniv |
language |
English |
description |
The Ekström Ice Shelf is one of numerous small ice shelves that fringe the coastline of western Dronning Maud Land, East Antarctica. Reconstructions of past ice-sheet extent in this area are poorly constrained, due to a lack of geomorphological evidence. Here, we present a compilation of geophysical surveys in front of and beneath the Ekström Ice Shelf, to identify and interpret evidence of past ice-sheet flow, extent and retreat. The sea floor beneath the Ekström Ice Shelf is dominated by an incised trough, which extends from the modern-day grounding line onto the continental shelf. Our surveys show that mega-scale glacial lineations cover most of the mouth of this trough, terminating 11 km away from the continental shelf break, indicating the most recent minimal extent of grounded ice in this region. Beneath the front ∼30 km of the ice shelf measured from the ice shelf edge towards the inland direction, the sea floor is characterised by an acoustically transparent sedimentary unit, up to 45 m thick. This is likely composed of subglacial till, further corroborating the presence of past grounded ice cover. Further inland, the sea floor becomes rougher, interpreted as a transition from subglacial tills to a crystalline bedrock, corresponding to the outcrop of the volcanic Explora Wedge at the sea floor. Ice retreat in this region appears to have happened rapidly in the centre of the incised trough, evidenced by a lack of overprinting of the lineations at the trough mouth. At the margins of the trough uniformly spaced recessional moraines suggest ice retreated more gradually. We estimate the palaeo-ice thickness at the calving front around the Last Glacial Maximum to have been at least 305 to 320 m, based on the depth of iceberg ploughmarks within the trough and sea level reconstructions. Given the similarity of the numerous small ice shelves along the Dronning Maud Land coast, these findings are likely representative for other ice shelves in this region and provide essential boundary conditions for palaeo ... |
format |
Article in Journal/Newspaper |
author |
Oetting, A Smith, EC Arndt, JE Dorschel, B Drews, R Ehlers, TA Gaedicke, C Hofstede, C Klages, JP Kuhn, G Lambrecht, A Läufer, A Mayer, C Tiedemann, R Wilhelms, F Eisen, O |
spellingShingle |
Oetting, A Smith, EC Arndt, JE Dorschel, B Drews, R Ehlers, TA Gaedicke, C Hofstede, C Klages, JP Kuhn, G Lambrecht, A Läufer, A Mayer, C Tiedemann, R Wilhelms, F Eisen, O Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica |
author_facet |
Oetting, A Smith, EC Arndt, JE Dorschel, B Drews, R Ehlers, TA Gaedicke, C Hofstede, C Klages, JP Kuhn, G Lambrecht, A Läufer, A Mayer, C Tiedemann, R Wilhelms, F Eisen, O |
author_sort |
Oetting, A |
title |
Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica |
title_short |
Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica |
title_full |
Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica |
title_fullStr |
Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica |
title_full_unstemmed |
Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica |
title_sort |
geomorphology and shallow sub-sea-floor structures underneath the ekström ice shelf, antarctica |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://eprints.whiterose.ac.uk/190057/ https://eprints.whiterose.ac.uk/190057/1/tc-16-2051-2022.pdf |
long_lat |
ENVELOPE(-8.000,-8.000,-71.000,-71.000) |
geographic |
Dronning Maud Land East Antarctica Ekström Ice Shelf |
geographic_facet |
Dronning Maud Land East Antarctica Ekström Ice Shelf |
genre |
Antarc* Antarctica Dronning Maud Land East Antarctica Ice Sheet Ice Shelf Ice Shelves The Cryosphere |
genre_facet |
Antarc* Antarctica Dronning Maud Land East Antarctica Ice Sheet Ice Shelf Ice Shelves The Cryosphere |
op_relation |
https://eprints.whiterose.ac.uk/190057/1/tc-16-2051-2022.pdf Oetting, A, Smith, EC orcid.org/0000-0002-8672-8259 , Arndt, JE et al. (13 more authors) (2022) Geomorphology and shallow sub-sea-floor structures underneath the Ekström Ice Shelf, Antarctica. The Cryosphere, 16 (5). pp. 2051-2066. ISSN 1994-0424 |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
_version_ |
1766262746709491712 |