An instability theory for the formation of ribbed moraine, drumlins and mega-scale glacial lineations
We present a theory for the coupled flow of ice, subglacial water and subglacial sediment, which is designed to represent the processes which occur at the bed of an ice sheet. The ice is assumed to flow as a Newtonian viscous fluid, the water can flow between the till and the ice as a thin film, whi...
Published in: | Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences |
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crroyalsociety:10.1098/rspa.2014.0185 2024-06-23T07:53:49+00:00 An instability theory for the formation of ribbed moraine, drumlins and mega-scale glacial lineations Fowler, A. C. Chapwanya, M. 2014 http://dx.doi.org/10.1098/rspa.2014.0185 https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.2014.0185 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspa.2014.0185 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences volume 470, issue 2171, page 20140185 ISSN 1364-5021 1471-2946 journal-article 2014 crroyalsociety https://doi.org/10.1098/rspa.2014.0185 2024-06-04T06:23:06Z We present a theory for the coupled flow of ice, subglacial water and subglacial sediment, which is designed to represent the processes which occur at the bed of an ice sheet. The ice is assumed to flow as a Newtonian viscous fluid, the water can flow between the till and the ice as a thin film, which may thicken to form streams or cavities, and the till is assumed to be transported, either through shearing by the ice, squeezing by pressure gradients in the till, or by fluvial sediment transport processes in streams or cavities. In previous studies, it was shown that the dependence of ice sliding velocity on effective pressure provided a mechanism for the generation of bedforms resembling ribbed moraine, while the dependence of fluvial sediment transport on water film depth provides a mechanism for the generation of bedforms resembling mega-scale glacial lineations. Here, we combine these two processes in a single model, and show that, depending largely on the granulometry of the till, instability can occur in a range of types which range from ribbed moraine through three-dimensional drumlins to mega-scale glacial lineations. Article in Journal/Newspaper Ice Sheet The Royal Society Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 470 2171 20140185 |
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Open Polar |
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The Royal Society |
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crroyalsociety |
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English |
description |
We present a theory for the coupled flow of ice, subglacial water and subglacial sediment, which is designed to represent the processes which occur at the bed of an ice sheet. The ice is assumed to flow as a Newtonian viscous fluid, the water can flow between the till and the ice as a thin film, which may thicken to form streams or cavities, and the till is assumed to be transported, either through shearing by the ice, squeezing by pressure gradients in the till, or by fluvial sediment transport processes in streams or cavities. In previous studies, it was shown that the dependence of ice sliding velocity on effective pressure provided a mechanism for the generation of bedforms resembling ribbed moraine, while the dependence of fluvial sediment transport on water film depth provides a mechanism for the generation of bedforms resembling mega-scale glacial lineations. Here, we combine these two processes in a single model, and show that, depending largely on the granulometry of the till, instability can occur in a range of types which range from ribbed moraine through three-dimensional drumlins to mega-scale glacial lineations. |
format |
Article in Journal/Newspaper |
author |
Fowler, A. C. Chapwanya, M. |
spellingShingle |
Fowler, A. C. Chapwanya, M. An instability theory for the formation of ribbed moraine, drumlins and mega-scale glacial lineations |
author_facet |
Fowler, A. C. Chapwanya, M. |
author_sort |
Fowler, A. C. |
title |
An instability theory for the formation of ribbed moraine, drumlins and mega-scale glacial lineations |
title_short |
An instability theory for the formation of ribbed moraine, drumlins and mega-scale glacial lineations |
title_full |
An instability theory for the formation of ribbed moraine, drumlins and mega-scale glacial lineations |
title_fullStr |
An instability theory for the formation of ribbed moraine, drumlins and mega-scale glacial lineations |
title_full_unstemmed |
An instability theory for the formation of ribbed moraine, drumlins and mega-scale glacial lineations |
title_sort |
instability theory for the formation of ribbed moraine, drumlins and mega-scale glacial lineations |
publisher |
The Royal Society |
publishDate |
2014 |
url |
http://dx.doi.org/10.1098/rspa.2014.0185 https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.2014.0185 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspa.2014.0185 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences volume 470, issue 2171, page 20140185 ISSN 1364-5021 1471-2946 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rspa.2014.0185 |
container_title |
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences |
container_volume |
470 |
container_issue |
2171 |
container_start_page |
20140185 |
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1802645639909081088 |