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 forme...
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Language: | English |
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Cambridge University Press (CUP)
1980
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Online Access: | http://dx.doi.org/10.1017/s0022143000015306 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000015306 |
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crcambridgeupr:10.1017/s0022143000015306 2024-06-16T07:40:12+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. 1980 http://dx.doi.org/10.1017/s0022143000015306 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000015306 en eng Cambridge University Press (CUP) Journal of Glaciology volume 25, issue 93, page 457-476 ISSN 0022-1430 1727-5652 journal-article 1980 crcambridgeupr https://doi.org/10.1017/s0022143000015306 2024-05-22T12:55:05Z 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-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 2–3 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 2–3 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. Article in Journal/Newspaper glacier* Journal of Glaciology Cambridge University Press Canada Journal of Glaciology 25 93 457 476 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
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-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 2–3 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 2–3 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. |
format |
Article in Journal/Newspaper |
author |
Moran, S. R. Clayton, Lee Hooke, R. Leb Fenton, M.M Andriashek, L.D. |
spellingShingle |
Moran, S. R. Clayton, Lee Hooke, R. Leb Fenton, M.M Andriashek, L.D. Glacier-Bed Landforms of The Prairie Region of North America |
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 |
1980 |
url |
http://dx.doi.org/10.1017/s0022143000015306 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000015306 |
geographic |
Canada |
geographic_facet |
Canada |
genre |
glacier* Journal of Glaciology |
genre_facet |
glacier* Journal of Glaciology |
op_source |
Journal of Glaciology volume 25, issue 93, page 457-476 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000015306 |
container_title |
Journal of Glaciology |
container_volume |
25 |
container_issue |
93 |
container_start_page |
457 |
op_container_end_page |
476 |
_version_ |
1802007054452260864 |