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Bedforms of Thwaites Glacier, West Antarctica: Character and Origin

R. B. Alley, N. Holschuh, D. R. MacAyeal, B. R. Parizek, L. Zoet, K. Riverman, A. Muto, K. Christianson, E. Clyne, S. Anandakrishnan, N. Stevens, (GHOST Collaboration), Bernd Kulessa Orcid Logo

Journal of Geophysical Research: Earth Surface, Volume: 126, Issue: 12

Swansea University Author: Bernd Kulessa Orcid Logo

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DOI (Published version): 10.1029/2021jf006339

Abstract

Bedforms of Thwaites Glacier, West Antarctica both record and affect ice flow, as shown by geophysical data and simple models. Thwaites Glacier flows across the tectonic fabric of the West Antarctic rift system with its bedrock highs and sedimentary basins. Swath radar and seismic surveys of the gla...

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Published in: Journal of Geophysical Research: Earth Surface
ISSN: 2169-9003 2169-9011
Published: American Geophysical Union (AGU) 2021
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URI: https://cronfa.swan.ac.uk/Record/cronfa58997
first_indexed 2021-12-20T06:55:36Z
last_indexed 2021-12-30T04:27:35Z
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Flutes end at prominent hard-bedded moats on stoss sides of the next topographic highs. We use simple models to show that ice flow against topography increases pressure between ice and till upglacier along the bed over a distance that scales with the topography. In this basal zone of high pressure, ice-contact water would be excluded, thus increasing basal drag by increasing ice-till coupling and till flux, removing till to allow bedrock erosion that creates moats. Till carried across highlands would then be deposited in lee-side positions forming bedforms that prograde downglacier over time, and that remain soft on top through feedbacks that match till-deformational fluxes from well upglacier of the topography. The bedforms of the part of Thwaites surveyed here are prominent because ice flow has persisted over a long time on this geological setting, not because ice flow is anomalous. 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spelling 2021-12-29T12:57:08.1285800 v2 58997 2021-12-10 Bedforms of Thwaites Glacier, West Antarctica: Character and Origin 52acda616e9f6073cbebf497def874c9 0000-0002-4830-4949 Bernd Kulessa Bernd Kulessa true false 2021-12-10 BGPS Bedforms of Thwaites Glacier, West Antarctica both record and affect ice flow, as shown by geophysical data and simple models. Thwaites Glacier flows across the tectonic fabric of the West Antarctic rift system with its bedrock highs and sedimentary basins. Swath radar and seismic surveys of the glacier bed have revealed soft-sediment flutes 100 m or more high extending 15 km or more across basins downglacier from bedrock highs. Flutes end at prominent hard-bedded moats on stoss sides of the next topographic highs. We use simple models to show that ice flow against topography increases pressure between ice and till upglacier along the bed over a distance that scales with the topography. In this basal zone of high pressure, ice-contact water would be excluded, thus increasing basal drag by increasing ice-till coupling and till flux, removing till to allow bedrock erosion that creates moats. Till carried across highlands would then be deposited in lee-side positions forming bedforms that prograde downglacier over time, and that remain soft on top through feedbacks that match till-deformational fluxes from well upglacier of the topography. The bedforms of the part of Thwaites surveyed here are prominent because ice flow has persisted over a long time on this geological setting, not because ice flow is anomalous. Bedform development likely has caused evolution of ice flow over time as till and lubricating water were redistributed, moats were eroded and bedforms grew. Journal Article Journal of Geophysical Research: Earth Surface 126 12 American Geophysical Union (AGU) 2169-9003 2169-9011 glacier bedforms; glacier history; Thwaites Glacier; swath radar; West Antarctic Ice Sheet; subglacial water 1 12 2021 2021-12-01 10.1029/2021jf006339 COLLEGE NANME Biosciences Geography and Physics School COLLEGE CODE BGPS Swansea University National Science Foundation (NSF). Grant Numbers: AGS-1338832, NSF-NERC-OPP-1738934; Heising-Simons Foundation (HSF). Grant Number: 2018-0769 2021-12-29T12:57:08.1285800 2021-12-10T19:44:26.0890550 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Geography R. B. Alley 1 N. Holschuh 2 D. R. MacAyeal 3 B. R. Parizek 4 L. Zoet 5 K. Riverman 6 A. Muto 7 K. Christianson 8 E. Clyne 9 S. Anandakrishnan 10 N. Stevens 11 (GHOST Collaboration) 12 Bernd Kulessa 0000-0002-4830-4949 13 58997__21874__dd4abab960a8422d9c2bf669f58e764e.pdf Alley 2021 Thwaites Glacier bedforms moats.pdf 2021-12-10T19:47:38.0328736 Output 2895032 application/pdf Version of Record true © 2021. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License true eng http://creativecommons.org/licenses/by-nc-nd/4.0/
title Bedforms of Thwaites Glacier, West Antarctica: Character and Origin
spellingShingle Bedforms of Thwaites Glacier, West Antarctica: Character and Origin
Bernd Kulessa
title_short Bedforms of Thwaites Glacier, West Antarctica: Character and Origin
title_full Bedforms of Thwaites Glacier, West Antarctica: Character and Origin
title_fullStr Bedforms of Thwaites Glacier, West Antarctica: Character and Origin
title_full_unstemmed Bedforms of Thwaites Glacier, West Antarctica: Character and Origin
title_sort Bedforms of Thwaites Glacier, West Antarctica: Character and Origin
author_id_str_mv 52acda616e9f6073cbebf497def874c9
author_id_fullname_str_mv 52acda616e9f6073cbebf497def874c9_***_Bernd Kulessa
author Bernd Kulessa
author2 R. B. Alley
N. Holschuh
D. R. MacAyeal
B. R. Parizek
L. Zoet
K. Riverman
A. Muto
K. Christianson
E. Clyne
S. Anandakrishnan
N. Stevens
(GHOST Collaboration)
Bernd Kulessa
format Journal article
container_title Journal of Geophysical Research: Earth Surface
container_volume 126
container_issue 12
publishDate 2021
institution Swansea University
issn 2169-9003
2169-9011
doi_str_mv 10.1029/2021jf006339
publisher American Geophysical Union (AGU)
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
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
document_store_str 1
active_str 0
description Bedforms of Thwaites Glacier, West Antarctica both record and affect ice flow, as shown by geophysical data and simple models. Thwaites Glacier flows across the tectonic fabric of the West Antarctic rift system with its bedrock highs and sedimentary basins. Swath radar and seismic surveys of the glacier bed have revealed soft-sediment flutes 100 m or more high extending 15 km or more across basins downglacier from bedrock highs. Flutes end at prominent hard-bedded moats on stoss sides of the next topographic highs. We use simple models to show that ice flow against topography increases pressure between ice and till upglacier along the bed over a distance that scales with the topography. In this basal zone of high pressure, ice-contact water would be excluded, thus increasing basal drag by increasing ice-till coupling and till flux, removing till to allow bedrock erosion that creates moats. Till carried across highlands would then be deposited in lee-side positions forming bedforms that prograde downglacier over time, and that remain soft on top through feedbacks that match till-deformational fluxes from well upglacier of the topography. The bedforms of the part of Thwaites surveyed here are prominent because ice flow has persisted over a long time on this geological setting, not because ice flow is anomalous. Bedform development likely has caused evolution of ice flow over time as till and lubricating water were redistributed, moats were eroded and bedforms grew.
published_date 2021-12-01T14:16:38Z
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score 11.247077

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