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Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica

Hannes Hollmann, Adam Treverrow, Leo E. Peters, Anya M. Reading, Bernd Kulessa Orcid Logo

Journal of Glaciology, Volume: 67, Issue: 265, Pages: 777 - 787

Swansea University Author: Bernd Kulessa Orcid Logo

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DOI (Published version): 10.1017/jog.2021.21

Abstract

We use seismic refraction data to investigate the firn structure across a suture zone on the Amery Ice Shelf, East Antarctica, and the possible role of glacier dynamics in firn evolution. In the downstream direction, the data reveal decreasing compressional-wave velocities and increasing penetration...

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Published in: Journal of Glaciology
ISSN: 0022-1430 1727-5652
Published: Cambridge University Press (CUP) 2021
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URI: https://cronfa.swan.ac.uk/Record/cronfa56893
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first_indexed 2021-05-20T08:15:52Z
last_indexed 2021-11-03T04:24:28Z
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spelling 2021-11-02T12:20:35.8422098 v2 56893 2021-05-18 Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica 52acda616e9f6073cbebf497def874c9 0000-0002-4830-4949 Bernd Kulessa Bernd Kulessa true false 2021-05-18 SGE We use seismic refraction data to investigate the firn structure across a suture zone on the Amery Ice Shelf, East Antarctica, and the possible role of glacier dynamics in firn evolution. In the downstream direction, the data reveal decreasing compressional-wave velocities and increasing penetration depth of the propagating wave in the firn layer, consistent with 1 m firn thickening every 6 km. The boundary between the Lambert Glacier unit to the west and a major suture zone and the Mawson Escarpment Ice Stream unit to the east, is marked by differences in firn thicknesses, compressional-wave velocities and seismic anisotropy in the across-flow direction. The latter does not contradict the presence of a single-maximum crystal orientation fabric oriented 45– away from the flow direction. This is consistent with the presence of transverse simple shear governing the region's underlying ice flow regime, in association with elevated strain along the suture zone. The confirmation and quantification of the implied dynamic coupling between firn and the underlying ice requires integration of future seismic refraction, coring and modelling studies. Because firn is estimated to cover 98% of the Antarctic continent any such coupling may have widespread relevance to ice-sheet evolution and flow. Journal Article Journal of Glaciology 67 265 777 787 Cambridge University Press (CUP) 0022-1430 1727-5652 Polar firn; seismics; snow mechanics 1 10 2021 2021-10-01 10.1017/jog.2021.21 COLLEGE NANME Geography COLLEGE CODE SGE Swansea University Other This research was supported under Australian Research Council’s Special Research Initiative for Antarctic Gateway Partnership (Project ID SR140300001). The seismic survey was supported by the Australian Antarctic Division (AAD) ASAC Project 2581 with Richard Coleman as Chief Investigator. 2021-11-02T12:20:35.8422098 2021-05-18T12:55:26.5083953 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Geography Hannes Hollmann 1 Adam Treverrow 2 Leo E. Peters 3 Anya M. Reading 4 Bernd Kulessa 0000-0002-4830-4949 5 56893__20217__65619af567f9482598c25b9a569987ed.pdf 56893.pdf 2021-06-22T12:36:13.3403436 Output 879711 application/pdf Version of Record true © The Author(s), 2021. This is an Open Access article, distributed under the terms of the Creative Commons Attribution license true eng http://creativecommons.org/licenses/by/4.0/
title Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica
spellingShingle Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica
Bernd Kulessa
title_short Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica
title_full Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica
title_fullStr Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica
title_full_unstemmed Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica
title_sort Seismic observations of a complex firn structure across the Amery Ice Shelf, East Antarctica
author_id_str_mv 52acda616e9f6073cbebf497def874c9
author_id_fullname_str_mv 52acda616e9f6073cbebf497def874c9_***_Bernd Kulessa
author Bernd Kulessa
author2 Hannes Hollmann
Adam Treverrow
Leo E. Peters
Anya M. Reading
Bernd Kulessa
format Journal article
container_title Journal of Glaciology
container_volume 67
container_issue 265
container_start_page 777
publishDate 2021
institution Swansea University
issn 0022-1430
1727-5652
doi_str_mv 10.1017/jog.2021.21
publisher Cambridge University Press (CUP)
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 We use seismic refraction data to investigate the firn structure across a suture zone on the Amery Ice Shelf, East Antarctica, and the possible role of glacier dynamics in firn evolution. In the downstream direction, the data reveal decreasing compressional-wave velocities and increasing penetration depth of the propagating wave in the firn layer, consistent with 1 m firn thickening every 6 km. The boundary between the Lambert Glacier unit to the west and a major suture zone and the Mawson Escarpment Ice Stream unit to the east, is marked by differences in firn thicknesses, compressional-wave velocities and seismic anisotropy in the across-flow direction. The latter does not contradict the presence of a single-maximum crystal orientation fabric oriented 45– away from the flow direction. This is consistent with the presence of transverse simple shear governing the region's underlying ice flow regime, in association with elevated strain along the suture zone. The confirmation and quantification of the implied dynamic coupling between firn and the underlying ice requires integration of future seismic refraction, coring and modelling studies. Because firn is estimated to cover 98% of the Antarctic continent any such coupling may have widespread relevance to ice-sheet evolution and flow.
published_date 2021-10-01T04:12:12Z
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score 11.013148

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