Till body morphology and structure related to glacier flow
Tills are described which occur in ridges and mounds arranged both parallel and transverse to the flow direction of the depositing glacier. Field localities are drawn from the English Midlands, Western Canada, and South Victoria Land, Antarctica. The tills retain textural and structural properties a...
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crwiley:10.1111/j.1502-3885.1977.tb00348.x 2024-09-15T17:43:32+00:00 Till body morphology and structure related to glacier flow SHAW, JOHN 1977 http://dx.doi.org/10.1111/j.1502-3885.1977.tb00348.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.1977.tb00348.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.1977.tb00348.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Boreas volume 6, issue 2, page 189-201 ISSN 0300-9483 1502-3885 journal-article 1977 crwiley https://doi.org/10.1111/j.1502-3885.1977.tb00348.x 2024-07-25T04:18:42Z Tills are described which occur in ridges and mounds arranged both parallel and transverse to the flow direction of the depositing glacier. Field localities are drawn from the English Midlands, Western Canada, and South Victoria Land, Antarctica. The tills retain textural and structural properties associated with glacial transport, and have suffered a minimum of redistribution suhsequent to their release from glacier ice. It is shown that ridges and mounds cannot he explained in terms of preferential till accretion. An alternative mechanism is presented in which form and structurc are a result of redistribution of debris in transport by secondary flows in ice. Flutings are longitudinal forms which are related to helicoidal flow cells. Fabric distributions, patterns of till thickness, and internal structure support the helicoidal flow hypothesis. Debris entrainment by Antarctic cold‐based glaciers is explained by consideration of the morphology and sedimentology of the ice margin and the pattern of glacier flow. Deposition by sublimation and melt‐out produces an upwards succession of (1) undisturbed proglacial deposits; (2) a complex of poorly sorted flow deposits intercalated with sorted and stratified water‐lain deposits; (3) foliated till with sub‐horizantal jointing and isolated clasts. A section shobbing this succession is described from Taylor Valley, Antarctica. Transverse asymmetric ridges are related to till stacking by over‐folding in the marginal compressive zone of cold‐based glaciers. Plastic deformation of the debris‐laden ice may be enhanced by incorporated salts. The folding process is illustrated by structures within Taylor glacier, and is used to explain Pleistocene landforms and structures in Shropshirc, England and Taylor Valley, Antarctica. Article in Journal/Newspaper Antarc* Antarctic Antarctica glacier* Taylor Glacier Victoria Land Wiley Online Library Boreas 6 2 189 201 |
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Wiley Online Library |
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English |
description |
Tills are described which occur in ridges and mounds arranged both parallel and transverse to the flow direction of the depositing glacier. Field localities are drawn from the English Midlands, Western Canada, and South Victoria Land, Antarctica. The tills retain textural and structural properties associated with glacial transport, and have suffered a minimum of redistribution suhsequent to their release from glacier ice. It is shown that ridges and mounds cannot he explained in terms of preferential till accretion. An alternative mechanism is presented in which form and structurc are a result of redistribution of debris in transport by secondary flows in ice. Flutings are longitudinal forms which are related to helicoidal flow cells. Fabric distributions, patterns of till thickness, and internal structure support the helicoidal flow hypothesis. Debris entrainment by Antarctic cold‐based glaciers is explained by consideration of the morphology and sedimentology of the ice margin and the pattern of glacier flow. Deposition by sublimation and melt‐out produces an upwards succession of (1) undisturbed proglacial deposits; (2) a complex of poorly sorted flow deposits intercalated with sorted and stratified water‐lain deposits; (3) foliated till with sub‐horizantal jointing and isolated clasts. A section shobbing this succession is described from Taylor Valley, Antarctica. Transverse asymmetric ridges are related to till stacking by over‐folding in the marginal compressive zone of cold‐based glaciers. Plastic deformation of the debris‐laden ice may be enhanced by incorporated salts. The folding process is illustrated by structures within Taylor glacier, and is used to explain Pleistocene landforms and structures in Shropshirc, England and Taylor Valley, Antarctica. |
format |
Article in Journal/Newspaper |
author |
SHAW, JOHN |
spellingShingle |
SHAW, JOHN Till body morphology and structure related to glacier flow |
author_facet |
SHAW, JOHN |
author_sort |
SHAW, JOHN |
title |
Till body morphology and structure related to glacier flow |
title_short |
Till body morphology and structure related to glacier flow |
title_full |
Till body morphology and structure related to glacier flow |
title_fullStr |
Till body morphology and structure related to glacier flow |
title_full_unstemmed |
Till body morphology and structure related to glacier flow |
title_sort |
till body morphology and structure related to glacier flow |
publisher |
Wiley |
publishDate |
1977 |
url |
http://dx.doi.org/10.1111/j.1502-3885.1977.tb00348.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.1977.tb00348.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.1977.tb00348.x |
genre |
Antarc* Antarctic Antarctica glacier* Taylor Glacier Victoria Land |
genre_facet |
Antarc* Antarctic Antarctica glacier* Taylor Glacier Victoria Land |
op_source |
Boreas volume 6, issue 2, page 189-201 ISSN 0300-9483 1502-3885 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1502-3885.1977.tb00348.x |
container_title |
Boreas |
container_volume |
6 |
container_issue |
2 |
container_start_page |
189 |
op_container_end_page |
201 |
_version_ |
1810490554757152768 |