The Dynamics of Marine Ice Sheets
Abstract Marine ice sheets rest on land that, for the most part, is below sea-level. Ice that flows across the grounding line, where the ice sheet becomes afloat, either calves into icebergs or forms a floating ice shelf joined to the ice sheet. At the grounding line there is a transition from ice-s...
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Cambridge University Press (CUP)
1979
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Online Access: | http://dx.doi.org/10.1017/s0022143000014726 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000014726 |
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crcambridgeupr:10.1017/s0022143000014726 2024-06-23T07:46:29+00:00 The Dynamics of Marine Ice Sheets Thomas, Robert H. 1979 http://dx.doi.org/10.1017/s0022143000014726 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000014726 en eng Cambridge University Press (CUP) Journal of Glaciology volume 24, issue 90, page 167-177 ISSN 0022-1430 1727-5652 journal-article 1979 crcambridgeupr https://doi.org/10.1017/s0022143000014726 2024-06-12T04:04:34Z Abstract Marine ice sheets rest on land that, for the most part, is below sea-level. Ice that flows across the grounding line, where the ice sheet becomes afloat, either calves into icebergs or forms a floating ice shelf joined to the ice sheet. At the grounding line there is a transition from ice-sheet dynamics to ice-shelf dynamics, and the creep-thinning rate in this region is very sensitive to sea depth; rising sea-level causes increased thinning-rates and grounding-line retreat, falling sea-level has the reverse effect. If the bedrock slopes down towards the centre of the ice sheet there may be only two stable modes: a freely-floating ice shelf or a marine ice sheet that extends to the edge of the continental shelf. Once started, collapse of such an ice sheet to form an ice shelf may take place extremely rapidly. Ice shelves which form in embayments of a marine ice sheet, or which are partially grounded, have a stabilizing influence since ice flowing across the grounding line has to push the ice shelf past its sides. Retreat of the grounding line tends to enlarge the ice shelf, which ultimately may become large enough to prevent excessive outflow from the ice sheet so that a new equilibrium grounding line is established; removal of the ice shelf would allow retreat to continue. During the late-Wisconsin glacial maximum there may have been marine ice sheets in the northern hemisphere but the only current example is the West Antarctic ice sheet. This is buttressed by the Ross and Ronne Ice Shelves, and if climatic warming were to prohibit the existence of these ice shelves then the ice sheet would collapse. Field observations suggest that, at present, the ice sheet may be advancing into parts of the Ross Ice Shelf. Such advance, however, would not ensure the security of the ice sheet since ice streams that drain to the north appear to flow directly into the sea with little or no ice shelf to buttress them. If these ice streams do not flow over a sufficiently high bedrock sill then they provide the most likely ... Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Iceberg* Journal of Glaciology Ross Ice Shelf Cambridge University Press Antarctic Buttress ENVELOPE(-57.083,-57.083,-63.550,-63.550) Ross Ice Shelf West Antarctic Ice Sheet Journal of Glaciology 24 90 167 177 |
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Open Polar |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Abstract Marine ice sheets rest on land that, for the most part, is below sea-level. Ice that flows across the grounding line, where the ice sheet becomes afloat, either calves into icebergs or forms a floating ice shelf joined to the ice sheet. At the grounding line there is a transition from ice-sheet dynamics to ice-shelf dynamics, and the creep-thinning rate in this region is very sensitive to sea depth; rising sea-level causes increased thinning-rates and grounding-line retreat, falling sea-level has the reverse effect. If the bedrock slopes down towards the centre of the ice sheet there may be only two stable modes: a freely-floating ice shelf or a marine ice sheet that extends to the edge of the continental shelf. Once started, collapse of such an ice sheet to form an ice shelf may take place extremely rapidly. Ice shelves which form in embayments of a marine ice sheet, or which are partially grounded, have a stabilizing influence since ice flowing across the grounding line has to push the ice shelf past its sides. Retreat of the grounding line tends to enlarge the ice shelf, which ultimately may become large enough to prevent excessive outflow from the ice sheet so that a new equilibrium grounding line is established; removal of the ice shelf would allow retreat to continue. During the late-Wisconsin glacial maximum there may have been marine ice sheets in the northern hemisphere but the only current example is the West Antarctic ice sheet. This is buttressed by the Ross and Ronne Ice Shelves, and if climatic warming were to prohibit the existence of these ice shelves then the ice sheet would collapse. Field observations suggest that, at present, the ice sheet may be advancing into parts of the Ross Ice Shelf. Such advance, however, would not ensure the security of the ice sheet since ice streams that drain to the north appear to flow directly into the sea with little or no ice shelf to buttress them. If these ice streams do not flow over a sufficiently high bedrock sill then they provide the most likely ... |
format |
Article in Journal/Newspaper |
author |
Thomas, Robert H. |
spellingShingle |
Thomas, Robert H. The Dynamics of Marine Ice Sheets |
author_facet |
Thomas, Robert H. |
author_sort |
Thomas, Robert H. |
title |
The Dynamics of Marine Ice Sheets |
title_short |
The Dynamics of Marine Ice Sheets |
title_full |
The Dynamics of Marine Ice Sheets |
title_fullStr |
The Dynamics of Marine Ice Sheets |
title_full_unstemmed |
The Dynamics of Marine Ice Sheets |
title_sort |
dynamics of marine ice sheets |
publisher |
Cambridge University Press (CUP) |
publishDate |
1979 |
url |
http://dx.doi.org/10.1017/s0022143000014726 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000014726 |
long_lat |
ENVELOPE(-57.083,-57.083,-63.550,-63.550) |
geographic |
Antarctic Buttress Ross Ice Shelf West Antarctic Ice Sheet |
geographic_facet |
Antarctic Buttress Ross Ice Shelf West Antarctic Ice Sheet |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Iceberg* Journal of Glaciology Ross Ice Shelf |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Iceberg* Journal of Glaciology Ross Ice Shelf |
op_source |
Journal of Glaciology volume 24, issue 90, page 167-177 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000014726 |
container_title |
Journal of Glaciology |
container_volume |
24 |
container_issue |
90 |
container_start_page |
167 |
op_container_end_page |
177 |
_version_ |
1802646290120572928 |