Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs
Ice-stream networks constitute the arteries of ice sheets through which large volumes of glacial ice are rapidly delivered from the continent to the ocean. Modifications in ice-stream networks have a major impact on ice sheet mass balance and global sea level. Reorganizations in the drainage network...
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ftcopernicus:oai:publications.copernicus.org:tc71440 2023-05-15T15:15:59+02:00 Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs Brouard, Etienne Lajeunesse, Patrick 2019-03-22 application/pdf https://doi.org/10.5194/tc-13-981-2019 https://tc.copernicus.org/articles/13/981/2019/ eng eng doi:10.5194/tc-13-981-2019 https://tc.copernicus.org/articles/13/981/2019/ eISSN: 1994-0424 Text 2019 ftcopernicus https://doi.org/10.5194/tc-13-981-2019 2020-07-20T16:22:54Z Ice-stream networks constitute the arteries of ice sheets through which large volumes of glacial ice are rapidly delivered from the continent to the ocean. Modifications in ice-stream networks have a major impact on ice sheet mass balance and global sea level. Reorganizations in the drainage network of ice streams have been reported in both modern and paleo-ice sheets and usually result in ice streams switching their trajectory and/or shutting down. While some hypotheses for the reorganization of ice streams have been proposed, the mechanisms that control the switching of ice streams remain poorly understood and documented. Here, we interpret a flow switch in an ice-stream system that occurred prior to the last glaciation on the northeastern Baffin Island shelf (Arctic Canada) through glacial erosion of a marginal trough, i.e., deep parallel-to-coast bedrock moats located up-ice of a cross-shelf trough. Shelf geomorphology imaged by high-resolution swath bathymetry and seismo-stratigraphic data in the area indicate the extension of ice streams from Scott and Hecla & Griper troughs towards the interior of the Laurentide Ice Sheet. Up-ice propagation of ice streams through a marginal trough is interpreted to have led to the piracy of the neighboring ice catchment that in turn induced an adjacent ice-stream flow switch and shutdown. These results suggest that competition for ice discharge between the two ice streams, which implies piracy of ice drainage basins via marginal troughs, was the driving mechanism behind ice flow switching. In turn, the enlargement of the ice catchment by piracy increased the volume and discharge of Scott Ice Stream, allowing it to erode deeper and flow farther on the continental shelf. Similar trough systems observed on many other glaciated continental shelves may be the product of such competition for ice discharge between catchments. Text Arctic Baffin Island Baffin Ice Sheet Copernicus Publications: E-Journals Arctic Baffin Island Canada The Cryosphere 13 3 981 996 |
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Open Polar |
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Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Ice-stream networks constitute the arteries of ice sheets through which large volumes of glacial ice are rapidly delivered from the continent to the ocean. Modifications in ice-stream networks have a major impact on ice sheet mass balance and global sea level. Reorganizations in the drainage network of ice streams have been reported in both modern and paleo-ice sheets and usually result in ice streams switching their trajectory and/or shutting down. While some hypotheses for the reorganization of ice streams have been proposed, the mechanisms that control the switching of ice streams remain poorly understood and documented. Here, we interpret a flow switch in an ice-stream system that occurred prior to the last glaciation on the northeastern Baffin Island shelf (Arctic Canada) through glacial erosion of a marginal trough, i.e., deep parallel-to-coast bedrock moats located up-ice of a cross-shelf trough. Shelf geomorphology imaged by high-resolution swath bathymetry and seismo-stratigraphic data in the area indicate the extension of ice streams from Scott and Hecla & Griper troughs towards the interior of the Laurentide Ice Sheet. Up-ice propagation of ice streams through a marginal trough is interpreted to have led to the piracy of the neighboring ice catchment that in turn induced an adjacent ice-stream flow switch and shutdown. These results suggest that competition for ice discharge between the two ice streams, which implies piracy of ice drainage basins via marginal troughs, was the driving mechanism behind ice flow switching. In turn, the enlargement of the ice catchment by piracy increased the volume and discharge of Scott Ice Stream, allowing it to erode deeper and flow farther on the continental shelf. Similar trough systems observed on many other glaciated continental shelves may be the product of such competition for ice discharge between catchments. |
format |
Text |
author |
Brouard, Etienne Lajeunesse, Patrick |
spellingShingle |
Brouard, Etienne Lajeunesse, Patrick Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs |
author_facet |
Brouard, Etienne Lajeunesse, Patrick |
author_sort |
Brouard, Etienne |
title |
Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs |
title_short |
Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs |
title_full |
Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs |
title_fullStr |
Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs |
title_full_unstemmed |
Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs |
title_sort |
ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs |
publishDate |
2019 |
url |
https://doi.org/10.5194/tc-13-981-2019 https://tc.copernicus.org/articles/13/981/2019/ |
geographic |
Arctic Baffin Island Canada |
geographic_facet |
Arctic Baffin Island Canada |
genre |
Arctic Baffin Island Baffin Ice Sheet |
genre_facet |
Arctic Baffin Island Baffin Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-13-981-2019 https://tc.copernicus.org/articles/13/981/2019/ |
op_doi |
https://doi.org/10.5194/tc-13-981-2019 |
container_title |
The Cryosphere |
container_volume |
13 |
container_issue |
3 |
container_start_page |
981 |
op_container_end_page |
996 |
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1766346311427162112 |