Bed conditions of Pine Island Glacier, West Antarctica
Although 90% of Antarctica's discharge occurs via its fast‐flowing ice streams, our ability to project future ice sheet response has been limited by poor observational constraints on the ice‐bed conditions used in numerical models to determine basal slip. We have helped address this observation...
Published in: | Journal of Geophysical Research: Earth Surface |
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Wiley-Blackwell
2017
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Online Access: | https://nrl.northumbria.ac.uk/id/eprint/34448/ https://doi.org/10.1002/2016JF004033 https://nrl.northumbria.ac.uk/id/eprint/34448/1/Brisbourne%20et%20al%20-%20Bed%20conditions%20of%20Pine%20Island%20Glacier,%20West%20Antarctica%20AAM.pdf |
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ftunivnorthumb:oai:nrl.northumbria.ac.uk:34448 2023-05-15T13:56:54+02:00 Bed conditions of Pine Island Glacier, West Antarctica Brisbourne, Alex Smith, Andrew M. Vaughan, David King, Edward Davies, Damon Bingham, Robert Smith, Emma Nias, Isabel Rosier, Sebastian 2017-01 text https://nrl.northumbria.ac.uk/id/eprint/34448/ https://doi.org/10.1002/2016JF004033 https://nrl.northumbria.ac.uk/id/eprint/34448/1/Brisbourne%20et%20al%20-%20Bed%20conditions%20of%20Pine%20Island%20Glacier,%20West%20Antarctica%20AAM.pdf en eng Wiley-Blackwell https://nrl.northumbria.ac.uk/id/eprint/34448/1/Brisbourne%20et%20al%20-%20Bed%20conditions%20of%20Pine%20Island%20Glacier,%20West%20Antarctica%20AAM.pdf Brisbourne, Alex, Smith, Andrew M., Vaughan, David, King, Edward, Davies, Damon, Bingham, Robert, Smith, Emma, Nias, Isabel and Rosier, Sebastian (2017) Bed conditions of Pine Island Glacier, West Antarctica. Journal of Geophysical Research: Earth Surface, 122 (1). pp. 419-433. ISSN 2169-9003 F800 Physical and Terrestrial Geographical and Environmental Sciences Article PeerReviewed 2017 ftunivnorthumb https://doi.org/10.1002/2016JF004033 2022-09-25T06:07:21Z Although 90% of Antarctica's discharge occurs via its fast‐flowing ice streams, our ability to project future ice sheet response has been limited by poor observational constraints on the ice‐bed conditions used in numerical models to determine basal slip. We have helped address this observational deficit by acquiring and analyzing a series of seismic reflection profiles to determine basal conditions beneath the main trunk and tributaries of Pine Island Glacier (PIG), West Antarctica. Seismic profiles indicate large‐scale sedimentary deposits. Combined with seismic reflection images, measured acoustic impedance values indicate relatively uniform bed conditions directly beneath the main trunk and tributaries, comprising a widespread reworked sediment layer with a dilated sediment lid of minimum thickness 1.5 ± 0.4 m. Beneath a slow‐moving intertributary region, a discrete low‐porosity sediment layer of 7 ± 3 m thickness is imaged. Despite considerable basal topography, seismic observations indicate that a till layer at the ice base is ubiquitous beneath PIG, which requires a highly mobile sediment body to maintain an abundant supply. These results are compatible with existing ice sheet models used to invert for basal shear stress: existing basal conditions upstream will not inhibit further rapid retreat of PIG if the high‐friction region currently restraining flow, directly upstream of the grounding line, is breached. However, small changes in the pressure regime at the bed, as a result of stress reorganization following retreat, may result in a less‐readily deformable bed and conditions which are less likely to maintain high ice‐flow rates. Article in Journal/Newspaper Antarc* Antarctica Antarctica Journal Ice Sheet Pine Island Pine Island Glacier West Antarctica Northumbria University, Newcastle: Northumbria Research Link (NRL) Pine Island Glacier ENVELOPE(-101.000,-101.000,-75.000,-75.000) West Antarctica Journal of Geophysical Research: Earth Surface 122 1 419 433 |
institution |
Open Polar |
collection |
Northumbria University, Newcastle: Northumbria Research Link (NRL) |
op_collection_id |
ftunivnorthumb |
language |
English |
topic |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
spellingShingle |
F800 Physical and Terrestrial Geographical and Environmental Sciences Brisbourne, Alex Smith, Andrew M. Vaughan, David King, Edward Davies, Damon Bingham, Robert Smith, Emma Nias, Isabel Rosier, Sebastian Bed conditions of Pine Island Glacier, West Antarctica |
topic_facet |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
description |
Although 90% of Antarctica's discharge occurs via its fast‐flowing ice streams, our ability to project future ice sheet response has been limited by poor observational constraints on the ice‐bed conditions used in numerical models to determine basal slip. We have helped address this observational deficit by acquiring and analyzing a series of seismic reflection profiles to determine basal conditions beneath the main trunk and tributaries of Pine Island Glacier (PIG), West Antarctica. Seismic profiles indicate large‐scale sedimentary deposits. Combined with seismic reflection images, measured acoustic impedance values indicate relatively uniform bed conditions directly beneath the main trunk and tributaries, comprising a widespread reworked sediment layer with a dilated sediment lid of minimum thickness 1.5 ± 0.4 m. Beneath a slow‐moving intertributary region, a discrete low‐porosity sediment layer of 7 ± 3 m thickness is imaged. Despite considerable basal topography, seismic observations indicate that a till layer at the ice base is ubiquitous beneath PIG, which requires a highly mobile sediment body to maintain an abundant supply. These results are compatible with existing ice sheet models used to invert for basal shear stress: existing basal conditions upstream will not inhibit further rapid retreat of PIG if the high‐friction region currently restraining flow, directly upstream of the grounding line, is breached. However, small changes in the pressure regime at the bed, as a result of stress reorganization following retreat, may result in a less‐readily deformable bed and conditions which are less likely to maintain high ice‐flow rates. |
format |
Article in Journal/Newspaper |
author |
Brisbourne, Alex Smith, Andrew M. Vaughan, David King, Edward Davies, Damon Bingham, Robert Smith, Emma Nias, Isabel Rosier, Sebastian |
author_facet |
Brisbourne, Alex Smith, Andrew M. Vaughan, David King, Edward Davies, Damon Bingham, Robert Smith, Emma Nias, Isabel Rosier, Sebastian |
author_sort |
Brisbourne, Alex |
title |
Bed conditions of Pine Island Glacier, West Antarctica |
title_short |
Bed conditions of Pine Island Glacier, West Antarctica |
title_full |
Bed conditions of Pine Island Glacier, West Antarctica |
title_fullStr |
Bed conditions of Pine Island Glacier, West Antarctica |
title_full_unstemmed |
Bed conditions of Pine Island Glacier, West Antarctica |
title_sort |
bed conditions of pine island glacier, west antarctica |
publisher |
Wiley-Blackwell |
publishDate |
2017 |
url |
https://nrl.northumbria.ac.uk/id/eprint/34448/ https://doi.org/10.1002/2016JF004033 https://nrl.northumbria.ac.uk/id/eprint/34448/1/Brisbourne%20et%20al%20-%20Bed%20conditions%20of%20Pine%20Island%20Glacier,%20West%20Antarctica%20AAM.pdf |
long_lat |
ENVELOPE(-101.000,-101.000,-75.000,-75.000) |
geographic |
Pine Island Glacier West Antarctica |
geographic_facet |
Pine Island Glacier West Antarctica |
genre |
Antarc* Antarctica Antarctica Journal Ice Sheet Pine Island Pine Island Glacier West Antarctica |
genre_facet |
Antarc* Antarctica Antarctica Journal Ice Sheet Pine Island Pine Island Glacier West Antarctica |
op_relation |
https://nrl.northumbria.ac.uk/id/eprint/34448/1/Brisbourne%20et%20al%20-%20Bed%20conditions%20of%20Pine%20Island%20Glacier,%20West%20Antarctica%20AAM.pdf Brisbourne, Alex, Smith, Andrew M., Vaughan, David, King, Edward, Davies, Damon, Bingham, Robert, Smith, Emma, Nias, Isabel and Rosier, Sebastian (2017) Bed conditions of Pine Island Glacier, West Antarctica. Journal of Geophysical Research: Earth Surface, 122 (1). pp. 419-433. ISSN 2169-9003 |
op_doi |
https://doi.org/10.1002/2016JF004033 |
container_title |
Journal of Geophysical Research: Earth Surface |
container_volume |
122 |
container_issue |
1 |
container_start_page |
419 |
op_container_end_page |
433 |
_version_ |
1766264491712970752 |