Structures and Ice Deformation in the White Glacier, Axel Heiberg Island, Northwest Territories, Canada
Abstract The major structures in the long, narrow tongue of a sub-polar valley glacier are described: namely, longitudinal foliation, crevasses, clear-ice layers related to crevasses, debris-rich layers (frequently referred to as thrust or shear planes in the past), and folds. The foliation is verti...
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Language: | English |
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Cambridge University Press (CUP)
1978
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Online Access: | http://dx.doi.org/10.1017/s0022143000021213 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000021213 |
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crcambridgeupr:10.1017/s0022143000021213 2024-09-15T17:56:52+00:00 Structures and Ice Deformation in the White Glacier, Axel Heiberg Island, Northwest Territories, Canada Hambrey, M.J. Müller, F. 1978 http://dx.doi.org/10.1017/s0022143000021213 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000021213 en eng Cambridge University Press (CUP) Journal of Glaciology volume 20, issue 82, page 41-66 ISSN 0022-1430 1727-5652 journal-article 1978 crcambridgeupr https://doi.org/10.1017/s0022143000021213 2024-07-31T04:03:43Z Abstract The major structures in the long, narrow tongue of a sub-polar valley glacier are described: namely, longitudinal foliation, crevasses, clear-ice layers related to crevasses, debris-rich layers (frequently referred to as thrust or shear planes in the past), and folds. The foliation is vertical, is as well-developed in the centre of the glacier as at the margins, and does not, apparently, form perpendicular to the principal compressive strain-rate axis, nor exactly parallel to a line of maximum shearing strain-rate, although it sometimes approximately coincides with the latter. The intensity of foliation development is not related to the magnitude of the strain-rates, but the structure consistently lies parallel to flow lines through the glacier. There is no critical extending strain-rate, as such, associated with the development of new crevasses. Some crevasses have formed where the principal extending strain-rate is as low as 0.004 a -1 while, in other areas, extending strain-rates of 0.163 a -1 have not always resulted in fracturing. Prominent clear-ice layers, referred to as crevasse traces as displayed at the glacier surface, have formed in crevasse belts parallel to the main fracture directions. These are interpreted either as tensional veins or as the result of the freezing of water in crevasses. Extension parallel to the layering occurs during flow and, near the snout, the surface dip decreases rapidly. The fact that the crevasse traces can be followed to the snout implies that fracture occurs almost to the bottom of the glacier in the source area of the traces. Near the snout, debris-rich layers have developed parallel to the crevasse traces; frequently these are marked by prominent ridge-like ice-cored moraines. It is suggested that these structures are formed by a combination of basal freezing and thrusting. Isoclinal and tight similar folds on all scales are present. Some may be formed by the passive deformation of clear-ice layers as a result of differential flow; others may arise from the ... Article in Journal/Newspaper Axel Heiberg Island glacier* Journal of Glaciology Northwest Territories Cambridge University Press Journal of Glaciology 20 82 41 66 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Abstract The major structures in the long, narrow tongue of a sub-polar valley glacier are described: namely, longitudinal foliation, crevasses, clear-ice layers related to crevasses, debris-rich layers (frequently referred to as thrust or shear planes in the past), and folds. The foliation is vertical, is as well-developed in the centre of the glacier as at the margins, and does not, apparently, form perpendicular to the principal compressive strain-rate axis, nor exactly parallel to a line of maximum shearing strain-rate, although it sometimes approximately coincides with the latter. The intensity of foliation development is not related to the magnitude of the strain-rates, but the structure consistently lies parallel to flow lines through the glacier. There is no critical extending strain-rate, as such, associated with the development of new crevasses. Some crevasses have formed where the principal extending strain-rate is as low as 0.004 a -1 while, in other areas, extending strain-rates of 0.163 a -1 have not always resulted in fracturing. Prominent clear-ice layers, referred to as crevasse traces as displayed at the glacier surface, have formed in crevasse belts parallel to the main fracture directions. These are interpreted either as tensional veins or as the result of the freezing of water in crevasses. Extension parallel to the layering occurs during flow and, near the snout, the surface dip decreases rapidly. The fact that the crevasse traces can be followed to the snout implies that fracture occurs almost to the bottom of the glacier in the source area of the traces. Near the snout, debris-rich layers have developed parallel to the crevasse traces; frequently these are marked by prominent ridge-like ice-cored moraines. It is suggested that these structures are formed by a combination of basal freezing and thrusting. Isoclinal and tight similar folds on all scales are present. Some may be formed by the passive deformation of clear-ice layers as a result of differential flow; others may arise from the ... |
format |
Article in Journal/Newspaper |
author |
Hambrey, M.J. Müller, F. |
spellingShingle |
Hambrey, M.J. Müller, F. Structures and Ice Deformation in the White Glacier, Axel Heiberg Island, Northwest Territories, Canada |
author_facet |
Hambrey, M.J. Müller, F. |
author_sort |
Hambrey, M.J. |
title |
Structures and Ice Deformation in the White Glacier, Axel Heiberg Island, Northwest Territories, Canada |
title_short |
Structures and Ice Deformation in the White Glacier, Axel Heiberg Island, Northwest Territories, Canada |
title_full |
Structures and Ice Deformation in the White Glacier, Axel Heiberg Island, Northwest Territories, Canada |
title_fullStr |
Structures and Ice Deformation in the White Glacier, Axel Heiberg Island, Northwest Territories, Canada |
title_full_unstemmed |
Structures and Ice Deformation in the White Glacier, Axel Heiberg Island, Northwest Territories, Canada |
title_sort |
structures and ice deformation in the white glacier, axel heiberg island, northwest territories, canada |
publisher |
Cambridge University Press (CUP) |
publishDate |
1978 |
url |
http://dx.doi.org/10.1017/s0022143000021213 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000021213 |
genre |
Axel Heiberg Island glacier* Journal of Glaciology Northwest Territories |
genre_facet |
Axel Heiberg Island glacier* Journal of Glaciology Northwest Territories |
op_source |
Journal of Glaciology volume 20, issue 82, page 41-66 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000021213 |
container_title |
Journal of Glaciology |
container_volume |
20 |
container_issue |
82 |
container_start_page |
41 |
op_container_end_page |
66 |
_version_ |
1810433043603652608 |