Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping
Glacial ripping involves glaciotectonic disintegration of rock hills and extensive removal of rock at the ice-sheet bed, triggered by hydraulic jacking caused by fluctuating water pressures. Evidence from eastern Sweden shows that glacial ripping caused significant subglacial erosion during the fina...
Published in: | Journal of Glaciology |
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Cambridge University Press
2023
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Online Access: | http://nora.nerc.ac.uk/id/eprint/533022/ https://nora.nerc.ac.uk/id/eprint/533022/1/drag-forces-at-the-ice-sheet-bed-and-resistance-of-hard-rock-obstacles-the-physics-of-glacial-ripping.pdf https://doi.org/10.1017/jog.2022.49 |
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ftnerc:oai:nora.nerc.ac.uk:533022 2023-05-15T16:13:00+02:00 Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping Krabbendam, Maarten Dioguardi, Fabio Arnhardt, Christian Roberson, Sam Hall, Adrian M. 2023-02 text http://nora.nerc.ac.uk/id/eprint/533022/ https://nora.nerc.ac.uk/id/eprint/533022/1/drag-forces-at-the-ice-sheet-bed-and-resistance-of-hard-rock-obstacles-the-physics-of-glacial-ripping.pdf https://doi.org/10.1017/jog.2022.49 en eng Cambridge University Press https://nora.nerc.ac.uk/id/eprint/533022/1/drag-forces-at-the-ice-sheet-bed-and-resistance-of-hard-rock-obstacles-the-physics-of-glacial-ripping.pdf Krabbendam, Maarten; Dioguardi, Fabio; Arnhardt, Christian; Roberson, Sam; Hall, Adrian M. 2023 Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping. Journal of Glaciology, 69 (273). 103-119. https://doi.org/10.1017/jog.2022.49 <https://doi.org/10.1017/jog.2022.49> cc_by_4 CC-BY Publication - Article PeerReviewed 2023 ftnerc https://doi.org/10.1017/jog.2022.49 2023-02-24T00:02:01Z Glacial ripping involves glaciotectonic disintegration of rock hills and extensive removal of rock at the ice-sheet bed, triggered by hydraulic jacking caused by fluctuating water pressures. Evidence from eastern Sweden shows that glacial ripping caused significant subglacial erosion during the final deglaciation of the Fennoscandian ice sheet, distinct from abrasion and plucking (quarrying). Here we analyse the ice drag forces exerted onto rock obstacles at the base of an ice sheet, and the resisting forces of such rock obstacles: glaciotectonic disintegration requires that ice drag forces exceed the resisting forces of the rock obstacle. We consider rock obstacles of different sizes, shapes and fracture patterns, informed by natural examples from eastern Sweden. Our analysis shows that limited overpressure events, unfavourable fracture patterns, low-transmissivity fractures, slow ice and streamlined rock hamper rock hill disintegration. Conversely, under fast ice flow and fluctuating water pressures, disintegration is possible if the rock hill contains subhorizontal, transmissive fractures. Rock steps on previously smooth, abraded surfaces, caused by hydraulic jacking, also enhance drag forces and can cause disintegration of a rock hill. Glacial ripping is a physically plausible erosion mechanism, under realistic glaciological conditions prevalent near ice margins. Article in Journal/Newspaper Fennoscandian Ice Sheet Journal of Glaciology Natural Environment Research Council: NERC Open Research Archive Journal of Glaciology 1 17 |
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Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Glacial ripping involves glaciotectonic disintegration of rock hills and extensive removal of rock at the ice-sheet bed, triggered by hydraulic jacking caused by fluctuating water pressures. Evidence from eastern Sweden shows that glacial ripping caused significant subglacial erosion during the final deglaciation of the Fennoscandian ice sheet, distinct from abrasion and plucking (quarrying). Here we analyse the ice drag forces exerted onto rock obstacles at the base of an ice sheet, and the resisting forces of such rock obstacles: glaciotectonic disintegration requires that ice drag forces exceed the resisting forces of the rock obstacle. We consider rock obstacles of different sizes, shapes and fracture patterns, informed by natural examples from eastern Sweden. Our analysis shows that limited overpressure events, unfavourable fracture patterns, low-transmissivity fractures, slow ice and streamlined rock hamper rock hill disintegration. Conversely, under fast ice flow and fluctuating water pressures, disintegration is possible if the rock hill contains subhorizontal, transmissive fractures. Rock steps on previously smooth, abraded surfaces, caused by hydraulic jacking, also enhance drag forces and can cause disintegration of a rock hill. Glacial ripping is a physically plausible erosion mechanism, under realistic glaciological conditions prevalent near ice margins. |
format |
Article in Journal/Newspaper |
author |
Krabbendam, Maarten Dioguardi, Fabio Arnhardt, Christian Roberson, Sam Hall, Adrian M. |
spellingShingle |
Krabbendam, Maarten Dioguardi, Fabio Arnhardt, Christian Roberson, Sam Hall, Adrian M. Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping |
author_facet |
Krabbendam, Maarten Dioguardi, Fabio Arnhardt, Christian Roberson, Sam Hall, Adrian M. |
author_sort |
Krabbendam, Maarten |
title |
Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping |
title_short |
Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping |
title_full |
Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping |
title_fullStr |
Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping |
title_full_unstemmed |
Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping |
title_sort |
drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping |
publisher |
Cambridge University Press |
publishDate |
2023 |
url |
http://nora.nerc.ac.uk/id/eprint/533022/ https://nora.nerc.ac.uk/id/eprint/533022/1/drag-forces-at-the-ice-sheet-bed-and-resistance-of-hard-rock-obstacles-the-physics-of-glacial-ripping.pdf https://doi.org/10.1017/jog.2022.49 |
genre |
Fennoscandian Ice Sheet Journal of Glaciology |
genre_facet |
Fennoscandian Ice Sheet Journal of Glaciology |
op_relation |
https://nora.nerc.ac.uk/id/eprint/533022/1/drag-forces-at-the-ice-sheet-bed-and-resistance-of-hard-rock-obstacles-the-physics-of-glacial-ripping.pdf Krabbendam, Maarten; Dioguardi, Fabio; Arnhardt, Christian; Roberson, Sam; Hall, Adrian M. 2023 Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping. Journal of Glaciology, 69 (273). 103-119. https://doi.org/10.1017/jog.2022.49 <https://doi.org/10.1017/jog.2022.49> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1017/jog.2022.49 |
container_title |
Journal of Glaciology |
container_start_page |
1 |
op_container_end_page |
17 |
_version_ |
1765998608545480704 |