Evidence for a Frozen Bed, Byrd Glacier, Antarctica
Ice thickness, computed within the fjord region of Byrd Glacier on the assumptions that Byrd Glacier is in mass-balance equilibrium and that ice velocity is entirely due to basal sliding, are on average 400 m less than measured ice thicknesses along a radio-echo profile. We consider four explanation...
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1991
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ftmaineuniv:oai:digitalcommons.library.umaine.edu:ers_facpub-1031 2023-05-15T13:58:55+02:00 Evidence for a Frozen Bed, Byrd Glacier, Antarctica Scofield, John P. Fastook, James L. Hughes, Terence J. 1991-01-01T08:00:00Z application/pdf https://digitalcommons.library.umaine.edu/ers_facpub/32 https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1031&context=ers_facpub unknown DigitalCommons@UMaine https://digitalcommons.library.umaine.edu/ers_facpub/32 https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1031&context=ers_facpub This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. In addition, no permission is required from the rights-holder(s) for educational uses. For other uses, you need to obtain permission from the rights-holder(s). Earth Science Faculty Scholarship Earth Sciences text 1991 ftmaineuniv 2023-03-12T18:49:12Z Ice thickness, computed within the fjord region of Byrd Glacier on the assumptions that Byrd Glacier is in mass-balance equilibrium and that ice velocity is entirely due to basal sliding, are on average 400 m less than measured ice thicknesses along a radio-echo profile. We consider four explanations for these differences: (1) active glacier ice is separated from a zone of stagnant ice near the base of the glacier by a shear zone at depth; (2) basal melting rates are some 8 m/yr; (3) internal shear occurs with no basal sliding in much of the region above the grounding zone; or (4) internal creep and basal sliding contribute to the flow velocity in varying proportions above the grounding zone. Large gradients of surface strain rate seem to invalidate the first explanation. Computed values of basal shear stress (140 to 200 kPa) provide insufficient frictional heat to melt the ice demanded by the second explanation. Both the third and fourth explanations were examined by making simplifying assumptions that prevented a truly quantitative evaluation of their merit. Nevertheless, there is no escaping the qualitative conclusion that internal shear contributes strongly to surface velocities measured on Byrd Glacier, as is postulated in both these explanations. Text Antarc* Antarctica Byrd Glacier The University of Maine: DigitalCommons@UMaine Byrd Byrd Glacier ENVELOPE(160.333,160.333,-80.250,-80.250) |
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The University of Maine: DigitalCommons@UMaine |
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ftmaineuniv |
language |
unknown |
topic |
Earth Sciences |
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Earth Sciences Scofield, John P. Fastook, James L. Hughes, Terence J. Evidence for a Frozen Bed, Byrd Glacier, Antarctica |
topic_facet |
Earth Sciences |
description |
Ice thickness, computed within the fjord region of Byrd Glacier on the assumptions that Byrd Glacier is in mass-balance equilibrium and that ice velocity is entirely due to basal sliding, are on average 400 m less than measured ice thicknesses along a radio-echo profile. We consider four explanations for these differences: (1) active glacier ice is separated from a zone of stagnant ice near the base of the glacier by a shear zone at depth; (2) basal melting rates are some 8 m/yr; (3) internal shear occurs with no basal sliding in much of the region above the grounding zone; or (4) internal creep and basal sliding contribute to the flow velocity in varying proportions above the grounding zone. Large gradients of surface strain rate seem to invalidate the first explanation. Computed values of basal shear stress (140 to 200 kPa) provide insufficient frictional heat to melt the ice demanded by the second explanation. Both the third and fourth explanations were examined by making simplifying assumptions that prevented a truly quantitative evaluation of their merit. Nevertheless, there is no escaping the qualitative conclusion that internal shear contributes strongly to surface velocities measured on Byrd Glacier, as is postulated in both these explanations. |
format |
Text |
author |
Scofield, John P. Fastook, James L. Hughes, Terence J. |
author_facet |
Scofield, John P. Fastook, James L. Hughes, Terence J. |
author_sort |
Scofield, John P. |
title |
Evidence for a Frozen Bed, Byrd Glacier, Antarctica |
title_short |
Evidence for a Frozen Bed, Byrd Glacier, Antarctica |
title_full |
Evidence for a Frozen Bed, Byrd Glacier, Antarctica |
title_fullStr |
Evidence for a Frozen Bed, Byrd Glacier, Antarctica |
title_full_unstemmed |
Evidence for a Frozen Bed, Byrd Glacier, Antarctica |
title_sort |
evidence for a frozen bed, byrd glacier, antarctica |
publisher |
DigitalCommons@UMaine |
publishDate |
1991 |
url |
https://digitalcommons.library.umaine.edu/ers_facpub/32 https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1031&context=ers_facpub |
long_lat |
ENVELOPE(160.333,160.333,-80.250,-80.250) |
geographic |
Byrd Byrd Glacier |
geographic_facet |
Byrd Byrd Glacier |
genre |
Antarc* Antarctica Byrd Glacier |
genre_facet |
Antarc* Antarctica Byrd Glacier |
op_source |
Earth Science Faculty Scholarship |
op_relation |
https://digitalcommons.library.umaine.edu/ers_facpub/32 https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1031&context=ers_facpub |
op_rights |
This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. In addition, no permission is required from the rights-holder(s) for educational uses. For other uses, you need to obtain permission from the rights-holder(s). |
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1766267286082027520 |