Glacier-Bed Landforms of the Prairie Region of North America
Abstract Two major types of terrain that formed at or near the bed of Pleistocene continental ice sheets are widespread throughout the prairie region of Canada and the United States. These are (1) glacial-thrust blocks and source depressions and (2) streamlined terrain. Glacial-thrust terrain formed...
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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/s0022143000030161 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000030161 |
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crcambridgeupr:10.1017/s0022143000030161 2024-04-07T07:52:40+00:00 Glacier-Bed Landforms of the Prairie Region of North America Moran, S. R. Clayton, Lee Hooke, R. LeB. Fenton, M. M. Andriashek, L. D. 1979 http://dx.doi.org/10.1017/s0022143000030161 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000030161 en eng Cambridge University Press (CUP) Journal of Glaciology volume 23, issue 89, page 423-424 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 1979 crcambridgeupr https://doi.org/10.1017/s0022143000030161 2024-03-08T00:30:18Z Abstract Two major types of terrain that formed at or near the bed of Pleistocene continental ice sheets are widespread throughout the prairie region of Canada and the United States. These are (1) glacial-thrust blocks and source depressions and (2) streamlined terrain. Glacial-thrust terrain formed where the glacier was frozen to the substrate and where elevated pore-water pressure decreased the shear strength of the substrate to a value less than that applied by the glacier. The marginal zone of ice sheets consisted of a frozen-bed zone, no more than 2 to 3 km wide in places, within which glacial-thrust blocks are large and angular. Up-glacier from this zone the thrust blocks are generally smaller and smoothed. Streamlined terrain begins 2 to 3 km behind known ice-margin positions and extends tens of kilometres up-glacier. Streamlined terrain formed in two ways: (1) erosion of the substrate as a consequence of basal sliding in the sub-marginal thawed-bed zone and (2) erosional smoothing accompanied by emplacement of till in the lee of thrust blocks where they were deposited and subsequently exposed to thawed-bed conditions as a result of further advance of the glacier. This paper has been accepted for publication in full in a future issue of the Journal of Glaciology . Article in Journal/Newspaper glacier* Journal of Glaciology Cambridge University Press Canada Journal of Glaciology 23 89 423 424 |
institution |
Open Polar |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
spellingShingle |
Earth-Surface Processes Moran, S. R. Clayton, Lee Hooke, R. LeB. Fenton, M. M. Andriashek, L. D. Glacier-Bed Landforms of the Prairie Region of North America |
topic_facet |
Earth-Surface Processes |
description |
Abstract Two major types of terrain that formed at or near the bed of Pleistocene continental ice sheets are widespread throughout the prairie region of Canada and the United States. These are (1) glacial-thrust blocks and source depressions and (2) streamlined terrain. Glacial-thrust terrain formed where the glacier was frozen to the substrate and where elevated pore-water pressure decreased the shear strength of the substrate to a value less than that applied by the glacier. The marginal zone of ice sheets consisted of a frozen-bed zone, no more than 2 to 3 km wide in places, within which glacial-thrust blocks are large and angular. Up-glacier from this zone the thrust blocks are generally smaller and smoothed. Streamlined terrain begins 2 to 3 km behind known ice-margin positions and extends tens of kilometres up-glacier. Streamlined terrain formed in two ways: (1) erosion of the substrate as a consequence of basal sliding in the sub-marginal thawed-bed zone and (2) erosional smoothing accompanied by emplacement of till in the lee of thrust blocks where they were deposited and subsequently exposed to thawed-bed conditions as a result of further advance of the glacier. This paper has been accepted for publication in full in a future issue of the Journal of Glaciology . |
format |
Article in Journal/Newspaper |
author |
Moran, S. R. Clayton, Lee Hooke, R. LeB. Fenton, M. M. Andriashek, L. D. |
author_facet |
Moran, S. R. Clayton, Lee Hooke, R. LeB. Fenton, M. M. Andriashek, L. D. |
author_sort |
Moran, S. R. |
title |
Glacier-Bed Landforms of the Prairie Region of North America |
title_short |
Glacier-Bed Landforms of the Prairie Region of North America |
title_full |
Glacier-Bed Landforms of the Prairie Region of North America |
title_fullStr |
Glacier-Bed Landforms of the Prairie Region of North America |
title_full_unstemmed |
Glacier-Bed Landforms of the Prairie Region of North America |
title_sort |
glacier-bed landforms of the prairie region of north america |
publisher |
Cambridge University Press (CUP) |
publishDate |
1979 |
url |
http://dx.doi.org/10.1017/s0022143000030161 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000030161 |
geographic |
Canada |
geographic_facet |
Canada |
genre |
glacier* Journal of Glaciology |
genre_facet |
glacier* Journal of Glaciology |
op_source |
Journal of Glaciology volume 23, issue 89, page 423-424 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000030161 |
container_title |
Journal of Glaciology |
container_volume |
23 |
container_issue |
89 |
container_start_page |
423 |
op_container_end_page |
424 |
_version_ |
1795668089956728832 |