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Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica

REbecca Schlegel, Tavi Murray Orcid Logo, Andrew M. Smith, Alex M. Brisbourne, Adam D. Booth, Edward C. King, Roger A. Clark

Journal of Geophysical Research: Earth Surface, Volume: 127, Issue: 1

Swansea University Authors: REbecca Schlegel, Tavi Murray Orcid Logo

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DOI (Published version): 10.1029/2021jf006349

Abstract

Basal properties beneath ice streams and glaciers are known to be a control for ice flow dynamics, hence knowledge of them is crucial for predicting sea level due to changes in glacial dynamics. Basal properties, processes and topography also drive the formation of subglacial landforms. Bed properti...

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Published in: Journal of Geophysical Research: Earth Surface
ISSN: 2169-9003 2169-9011
Published: American Geophysical Union (AGU) 2022
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URI: https://cronfa.swan.ac.uk/Record/cronfa59052
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spelling 2022-10-26T14:57:35.6950088 v2 59052 2021-12-30 Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica 413f0697ac45c41cbb8f45aa60e4ff71 REbecca Schlegel REbecca Schlegel true false 8d6e71df690e725cd44191006dac31da 0000-0001-6714-6512 Tavi Murray Tavi Murray true false 2021-12-30 SGE Basal properties beneath ice streams and glaciers are known to be a control for ice flow dynamics, hence knowledge of them is crucial for predicting sea level due to changes in glacial dynamics. Basal properties, processes and topography also drive the formation of subglacial landforms. Bed properties beneath Rutford Ice Stream (West Antarctica) have previously been described using seismic acoustic impedance measurements at a sparse spatial coverage. Here, we derive bed properties in a 15 x 17 km grid of surface radar data with coverage and sampling much higher than previous seismic studies. Bed reflection amplitudes in surface radar data were calibrated using sediment porosities (ranging from 0.4 – 0.5) derived from seismic acoustic impedance. We find the bed properties are spatially variable, consisting of low porosity material in some areas and soft sediment in other areas. Comparison of seismic and surface radar data imply the low porosity material to be a consolidated sediment or sedimentary rock. Mega-scale glacial lineations (MSGLs) are ubiquitous on the bed and consist of soft, high porosity, probably deforming sediment, consistent with previous interpretations of MSGLs. We find some MSGLs have high reflectivity on their crest, interpreted as water bodies overlying high porosity sediment, whereas the trough around and the upstream end of some landforms consist of low porosity material. Integrating these different observations, we place constraints on possible explanations for the occurrence of water on the crest of landforms. Journal Article Journal of Geophysical Research: Earth Surface 127 1 American Geophysical Union (AGU) 2169-9003 2169-9011 Ice stream; Bed properties; Radar Reflectivity; West Antarctica 7 1 2022 2022-01-07 10.1029/2021jf006349 COLLEGE NANME Geography COLLEGE CODE SGE Swansea University SU Library paid the OA fee (TA Institutional Deal) Natural Environment Research Council NE/G013187/1; NE/G014159/1 2022-10-26T14:57:35.6950088 2021-12-30T10:35:09.7843382 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Geography REbecca Schlegel 1 Tavi Murray 0000-0001-6714-6512 2 Andrew M. Smith 3 Alex M. Brisbourne 4 Adam D. Booth 5 Edward C. King 6 Roger A. Clark 7 59052__22074__c2daade54bf246828360824b2a098897.pdf 59052.pdf 2022-01-07T13:11:29.6021146 Output 3420357 application/pdf Version of Record true © 2021. The Authors. This is an open access article under the terms of the Creative Commons Attribution License true eng http://creativecommons.org/licenses/by/4.0/
title Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica
spellingShingle Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica
REbecca Schlegel
Tavi Murray
title_short Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica
title_full Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica
title_fullStr Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica
title_full_unstemmed Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica
title_sort Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica
author_id_str_mv 413f0697ac45c41cbb8f45aa60e4ff71
8d6e71df690e725cd44191006dac31da
author_id_fullname_str_mv 413f0697ac45c41cbb8f45aa60e4ff71_***_REbecca Schlegel
8d6e71df690e725cd44191006dac31da_***_Tavi Murray
author REbecca Schlegel
Tavi Murray
author2 REbecca Schlegel
Tavi Murray
Andrew M. Smith
Alex M. Brisbourne
Adam D. Booth
Edward C. King
Roger A. Clark
format Journal article
container_title Journal of Geophysical Research: Earth Surface
container_volume 127
container_issue 1
publishDate 2022
institution Swansea University
issn 2169-9003
2169-9011
doi_str_mv 10.1029/2021jf006349
publisher American Geophysical Union (AGU)
college_str Faculty of Science and Engineering
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hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Geography{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Geography
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description Basal properties beneath ice streams and glaciers are known to be a control for ice flow dynamics, hence knowledge of them is crucial for predicting sea level due to changes in glacial dynamics. Basal properties, processes and topography also drive the formation of subglacial landforms. Bed properties beneath Rutford Ice Stream (West Antarctica) have previously been described using seismic acoustic impedance measurements at a sparse spatial coverage. Here, we derive bed properties in a 15 x 17 km grid of surface radar data with coverage and sampling much higher than previous seismic studies. Bed reflection amplitudes in surface radar data were calibrated using sediment porosities (ranging from 0.4 – 0.5) derived from seismic acoustic impedance. We find the bed properties are spatially variable, consisting of low porosity material in some areas and soft sediment in other areas. Comparison of seismic and surface radar data imply the low porosity material to be a consolidated sediment or sedimentary rock. Mega-scale glacial lineations (MSGLs) are ubiquitous on the bed and consist of soft, high porosity, probably deforming sediment, consistent with previous interpretations of MSGLs. We find some MSGLs have high reflectivity on their crest, interpreted as water bodies overlying high porosity sediment, whereas the trough around and the upstream end of some landforms consist of low porosity material. Integrating these different observations, we place constraints on possible explanations for the occurrence of water on the crest of landforms.
published_date 2022-01-07T04:16:03Z
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