Emergent Drumlins and their Clones; From Till Dilatancy to Flow Instabilities
Subglacial bedforms are a range of landforms (10 – 105 m in length) shaped mostly in glacial sediments and are abundant on ice sheet beds. Numerous explanations for their generation, especially of drumlins, have been proposed. Rather than viewing them as resulting from erosion or deposition directly...
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International Glaciological Society
2010
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Online Access: | https://eprints.whiterose.ac.uk/83511/ https://eprints.whiterose.ac.uk/83511/11/s7.pdf https://doi.org/10.3189/002214311796406068 |
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ftleedsuniv:oai:eprints.whiterose.ac.uk:83511 2023-05-15T16:41:07+02:00 Emergent Drumlins and their Clones; From Till Dilatancy to Flow Instabilities Clark, C.D. 2010-12-01 text https://eprints.whiterose.ac.uk/83511/ https://eprints.whiterose.ac.uk/83511/11/s7.pdf https://doi.org/10.3189/002214311796406068 en eng International Glaciological Society https://eprints.whiterose.ac.uk/83511/11/s7.pdf Clark, C.D. (2010) Emergent Drumlins and their Clones; From Till Dilatancy to Flow Instabilities. Journal of Glaciology , 56 (200). 1011 - 1025. ISSN 1727-5652 Article PeerReviewed 2010 ftleedsuniv https://doi.org/10.3189/002214311796406068 2023-01-30T21:30:42Z Subglacial bedforms are a range of landforms (10 – 105 m in length) shaped mostly in glacial sediments and are abundant on ice sheet beds. Numerous explanations for their generation, especially of drumlins, have been proposed. Rather than viewing them as resulting from erosion or deposition directly by ice, Smalley and Unwin (1968) proposed that both might occur simultaneously if, beneath the glacier, a layer of lubricating sediment existed and ‘flowed’, conducting geomorphic work (erosion, deposition, shaping) of its own. This idea appears to have steered the field, leading perhaps to final resolution of the centuries-old problem of drumlin genesis. Here, I trace how the idea evolved, leading to the conclusion that subglacial bedforms are emergent phenomena arising from self-organisation in the coupled flow of ice, sediment and water. The ubiquity and patterning of bedforms appears to be well explained by a naturally-arising flow instability in the subglacial system, and which has been demonstrated by analytical and numerical modelling. A problem for the instability theory is an apparent mismatch between predicted and observed sedimentological properties of bedforms. A distinction is made between emergent-drumlins, drumlin-clones and obstacle-drumlins which helps explain some apparent contradictions, and a conceptual framework is erected that might form a basis for confrontation of the theory with the wealth of observational evidence that exists. Article in Journal/Newspaper Ice Sheet Journal of Glaciology White Rose Research Online (Universities of Leeds, Sheffield & York) Unwin ENVELOPE(-57.894,-57.894,-63.328,-63.328) Journal of Glaciology 56 200 1011 1025 |
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Open Polar |
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White Rose Research Online (Universities of Leeds, Sheffield & York) |
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ftleedsuniv |
language |
English |
description |
Subglacial bedforms are a range of landforms (10 – 105 m in length) shaped mostly in glacial sediments and are abundant on ice sheet beds. Numerous explanations for their generation, especially of drumlins, have been proposed. Rather than viewing them as resulting from erosion or deposition directly by ice, Smalley and Unwin (1968) proposed that both might occur simultaneously if, beneath the glacier, a layer of lubricating sediment existed and ‘flowed’, conducting geomorphic work (erosion, deposition, shaping) of its own. This idea appears to have steered the field, leading perhaps to final resolution of the centuries-old problem of drumlin genesis. Here, I trace how the idea evolved, leading to the conclusion that subglacial bedforms are emergent phenomena arising from self-organisation in the coupled flow of ice, sediment and water. The ubiquity and patterning of bedforms appears to be well explained by a naturally-arising flow instability in the subglacial system, and which has been demonstrated by analytical and numerical modelling. A problem for the instability theory is an apparent mismatch between predicted and observed sedimentological properties of bedforms. A distinction is made between emergent-drumlins, drumlin-clones and obstacle-drumlins which helps explain some apparent contradictions, and a conceptual framework is erected that might form a basis for confrontation of the theory with the wealth of observational evidence that exists. |
format |
Article in Journal/Newspaper |
author |
Clark, C.D. |
spellingShingle |
Clark, C.D. Emergent Drumlins and their Clones; From Till Dilatancy to Flow Instabilities |
author_facet |
Clark, C.D. |
author_sort |
Clark, C.D. |
title |
Emergent Drumlins and their Clones; From Till Dilatancy to Flow Instabilities |
title_short |
Emergent Drumlins and their Clones; From Till Dilatancy to Flow Instabilities |
title_full |
Emergent Drumlins and their Clones; From Till Dilatancy to Flow Instabilities |
title_fullStr |
Emergent Drumlins and their Clones; From Till Dilatancy to Flow Instabilities |
title_full_unstemmed |
Emergent Drumlins and their Clones; From Till Dilatancy to Flow Instabilities |
title_sort |
emergent drumlins and their clones; from till dilatancy to flow instabilities |
publisher |
International Glaciological Society |
publishDate |
2010 |
url |
https://eprints.whiterose.ac.uk/83511/ https://eprints.whiterose.ac.uk/83511/11/s7.pdf https://doi.org/10.3189/002214311796406068 |
long_lat |
ENVELOPE(-57.894,-57.894,-63.328,-63.328) |
geographic |
Unwin |
geographic_facet |
Unwin |
genre |
Ice Sheet Journal of Glaciology |
genre_facet |
Ice Sheet Journal of Glaciology |
op_relation |
https://eprints.whiterose.ac.uk/83511/11/s7.pdf Clark, C.D. (2010) Emergent Drumlins and their Clones; From Till Dilatancy to Flow Instabilities. Journal of Glaciology , 56 (200). 1011 - 1025. ISSN 1727-5652 |
op_doi |
https://doi.org/10.3189/002214311796406068 |
container_title |
Journal of Glaciology |
container_volume |
56 |
container_issue |
200 |
container_start_page |
1011 |
op_container_end_page |
1025 |
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1766031554395504640 |