Formation of ribbed bedforms below shear margins and lobes of palaeo-ice streams
Conceptual ice stream land systems derived from geomorphological and sedimentological observations provide constraints on ice–meltwater–till–bedrock interactions on palaeo-ice stream beds. Within these land systems, the spatial distribution and formation processes of ribbed bedforms remain unclear....
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Copernicus Publications
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Online Access: | https://doi.org/10.5194/tc-15-2889-2021 https://tc.copernicus.org/articles/15/2889/2021/tc-15-2889-2021.pdf https://doaj.org/article/bb0c80273ebe4492899d5e7e5b4a8451 |
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fttriple:oai:gotriple.eu:oai:doaj.org/article:bb0c80273ebe4492899d5e7e5b4a8451 2023-05-15T16:41:05+02:00 Formation of ribbed bedforms below shear margins and lobes of palaeo-ice streams J. Vérité É. Ravier O. Bourgeois S. Pochat T. Lelandais R. Mourgues C. D. Clark P. Bessin D. Peigné N. Atkinson 2021-06-01 https://doi.org/10.5194/tc-15-2889-2021 https://tc.copernicus.org/articles/15/2889/2021/tc-15-2889-2021.pdf https://doaj.org/article/bb0c80273ebe4492899d5e7e5b4a8451 en eng Copernicus Publications doi:10.5194/tc-15-2889-2021 1994-0416 1994-0424 https://tc.copernicus.org/articles/15/2889/2021/tc-15-2889-2021.pdf https://doaj.org/article/bb0c80273ebe4492899d5e7e5b4a8451 undefined The Cryosphere, Vol 15, Pp 2889-2916 (2021) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2021 fttriple https://doi.org/10.5194/tc-15-2889-2021 2023-01-22T19:09:40Z Conceptual ice stream land systems derived from geomorphological and sedimentological observations provide constraints on ice–meltwater–till–bedrock interactions on palaeo-ice stream beds. Within these land systems, the spatial distribution and formation processes of ribbed bedforms remain unclear. We explore the conditions under which these bedforms may develop and their spatial organization with (i) an experimental model that reproduces the dynamics of ice streams and subglacial land systems and (ii) an analysis of the distribution of ribbed bedforms on selected examples of palaeo-ice stream beds of the Laurentide Ice Sheet. We find that a specific kind of ribbed bedform can develop subglacially through soft-bed deformation, where the ice flow undergoes lateral or longitudinal velocity gradients and the ice–bed interface is unlubricated; oblique ribbed bedforms develop beneath lateral shear margins, whereas transverse ribbed bedforms develop below frontal lobes. We infer that (i) ribbed bedforms strike orthogonally to the compressing axis of the horizontal strain ellipse of the ice surface and (ii) their development reveals distinctive types of subglacial drainage patterns: linked cavities below lateral shear margins and efficient meltwater channels below frontal lobes. These ribbed bedforms may act as convenient geomorphic markers to reconstruct lateral and frontal margins, constrain ice flow dynamics, and infer meltwater drainage characteristics of palaeo-ice streams. Article in Journal/Newspaper Ice Sheet The Cryosphere Unknown The Cryosphere 15 6 2889 2916 |
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language |
English |
topic |
geo envir |
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geo envir J. Vérité É. Ravier O. Bourgeois S. Pochat T. Lelandais R. Mourgues C. D. Clark P. Bessin D. Peigné N. Atkinson Formation of ribbed bedforms below shear margins and lobes of palaeo-ice streams |
topic_facet |
geo envir |
description |
Conceptual ice stream land systems derived from geomorphological and sedimentological observations provide constraints on ice–meltwater–till–bedrock interactions on palaeo-ice stream beds. Within these land systems, the spatial distribution and formation processes of ribbed bedforms remain unclear. We explore the conditions under which these bedforms may develop and their spatial organization with (i) an experimental model that reproduces the dynamics of ice streams and subglacial land systems and (ii) an analysis of the distribution of ribbed bedforms on selected examples of palaeo-ice stream beds of the Laurentide Ice Sheet. We find that a specific kind of ribbed bedform can develop subglacially through soft-bed deformation, where the ice flow undergoes lateral or longitudinal velocity gradients and the ice–bed interface is unlubricated; oblique ribbed bedforms develop beneath lateral shear margins, whereas transverse ribbed bedforms develop below frontal lobes. We infer that (i) ribbed bedforms strike orthogonally to the compressing axis of the horizontal strain ellipse of the ice surface and (ii) their development reveals distinctive types of subglacial drainage patterns: linked cavities below lateral shear margins and efficient meltwater channels below frontal lobes. These ribbed bedforms may act as convenient geomorphic markers to reconstruct lateral and frontal margins, constrain ice flow dynamics, and infer meltwater drainage characteristics of palaeo-ice streams. |
format |
Article in Journal/Newspaper |
author |
J. Vérité É. Ravier O. Bourgeois S. Pochat T. Lelandais R. Mourgues C. D. Clark P. Bessin D. Peigné N. Atkinson |
author_facet |
J. Vérité É. Ravier O. Bourgeois S. Pochat T. Lelandais R. Mourgues C. D. Clark P. Bessin D. Peigné N. Atkinson |
author_sort |
J. Vérité |
title |
Formation of ribbed bedforms below shear margins and lobes of palaeo-ice streams |
title_short |
Formation of ribbed bedforms below shear margins and lobes of palaeo-ice streams |
title_full |
Formation of ribbed bedforms below shear margins and lobes of palaeo-ice streams |
title_fullStr |
Formation of ribbed bedforms below shear margins and lobes of palaeo-ice streams |
title_full_unstemmed |
Formation of ribbed bedforms below shear margins and lobes of palaeo-ice streams |
title_sort |
formation of ribbed bedforms below shear margins and lobes of palaeo-ice streams |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-2889-2021 https://tc.copernicus.org/articles/15/2889/2021/tc-15-2889-2021.pdf https://doaj.org/article/bb0c80273ebe4492899d5e7e5b4a8451 |
genre |
Ice Sheet The Cryosphere |
genre_facet |
Ice Sheet The Cryosphere |
op_source |
The Cryosphere, Vol 15, Pp 2889-2916 (2021) |
op_relation |
doi:10.5194/tc-15-2889-2021 1994-0416 1994-0424 https://tc.copernicus.org/articles/15/2889/2021/tc-15-2889-2021.pdf https://doaj.org/article/bb0c80273ebe4492899d5e7e5b4a8451 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-15-2889-2021 |
container_title |
The Cryosphere |
container_volume |
15 |
container_issue |
6 |
container_start_page |
2889 |
op_container_end_page |
2916 |
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1766031524545691648 |