Debris-bed friction during glacier sliding with ice–bed separation
Abstract Theory and experiments indicate that ice–bed separation during glacier slip over 2-D hard beds causes basal shear stress to reach a maximum at a particular slip velocity and decrease at higher velocities. We use the sliding theory of Lliboutry (1968) to explore how friction between debris p...
Published in: | Annals of Glaciology |
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Language: | English |
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Cambridge University Press (CUP)
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Online Access: | http://dx.doi.org/10.1017/aog.2019.46 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000466 |
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crcambridgeupr:10.1017/aog.2019.46 2024-09-15T17:39:53+00:00 Debris-bed friction during glacier sliding with ice–bed separation Iverson, Neal R. Helanow, Christian Zoet, Lucas K. 2019 http://dx.doi.org/10.1017/aog.2019.46 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000466 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Annals of Glaciology volume 60, issue 80, page 30-36 ISSN 0260-3055 1727-5644 journal-article 2019 crcambridgeupr https://doi.org/10.1017/aog.2019.46 2024-09-04T04:03:15Z Abstract Theory and experiments indicate that ice–bed separation during glacier slip over 2-D hard beds causes basal shear stress to reach a maximum at a particular slip velocity and decrease at higher velocities. We use the sliding theory of Lliboutry (1968) to explore how friction between debris particles in sliding ice and a rock bed affects this relationship between shear stress and slip velocity. Particle–bed contact forces and associated debris friction increase with increasing slip velocity, owing to increased rates of ice convergence with up-glacier facing surfaces. However, debris friction on diminished areas of the bed counteracts this effect as cavities grow. Thus, friction from debris alone increases only slightly with slip velocity, and for sediment particles larger than ~60 mm in diameter, debris friction peaks and decreases with increasing slip velocity. The effect on the sliding relationship is to steepen its rising limb and shift its shear stress peak to a slightly higher velocity. These results, which exclude the effect of debris friction on cavity size and debris concentrations above ~15%, indicate that the effect of debris in ice is to increase basal shear stress but not significantly change the form of the sliding relationship. Article in Journal/Newspaper Annals of Glaciology Cambridge University Press Annals of Glaciology 60 80 30 36 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Theory and experiments indicate that ice–bed separation during glacier slip over 2-D hard beds causes basal shear stress to reach a maximum at a particular slip velocity and decrease at higher velocities. We use the sliding theory of Lliboutry (1968) to explore how friction between debris particles in sliding ice and a rock bed affects this relationship between shear stress and slip velocity. Particle–bed contact forces and associated debris friction increase with increasing slip velocity, owing to increased rates of ice convergence with up-glacier facing surfaces. However, debris friction on diminished areas of the bed counteracts this effect as cavities grow. Thus, friction from debris alone increases only slightly with slip velocity, and for sediment particles larger than ~60 mm in diameter, debris friction peaks and decreases with increasing slip velocity. The effect on the sliding relationship is to steepen its rising limb and shift its shear stress peak to a slightly higher velocity. These results, which exclude the effect of debris friction on cavity size and debris concentrations above ~15%, indicate that the effect of debris in ice is to increase basal shear stress but not significantly change the form of the sliding relationship. |
format |
Article in Journal/Newspaper |
author |
Iverson, Neal R. Helanow, Christian Zoet, Lucas K. |
spellingShingle |
Iverson, Neal R. Helanow, Christian Zoet, Lucas K. Debris-bed friction during glacier sliding with ice–bed separation |
author_facet |
Iverson, Neal R. Helanow, Christian Zoet, Lucas K. |
author_sort |
Iverson, Neal R. |
title |
Debris-bed friction during glacier sliding with ice–bed separation |
title_short |
Debris-bed friction during glacier sliding with ice–bed separation |
title_full |
Debris-bed friction during glacier sliding with ice–bed separation |
title_fullStr |
Debris-bed friction during glacier sliding with ice–bed separation |
title_full_unstemmed |
Debris-bed friction during glacier sliding with ice–bed separation |
title_sort |
debris-bed friction during glacier sliding with ice–bed separation |
publisher |
Cambridge University Press (CUP) |
publishDate |
2019 |
url |
http://dx.doi.org/10.1017/aog.2019.46 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305519000466 |
genre |
Annals of Glaciology |
genre_facet |
Annals of Glaciology |
op_source |
Annals of Glaciology volume 60, issue 80, page 30-36 ISSN 0260-3055 1727-5644 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/aog.2019.46 |
container_title |
Annals of Glaciology |
container_volume |
60 |
container_issue |
80 |
container_start_page |
30 |
op_container_end_page |
36 |
_version_ |
1810483185287430144 |