Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming
Basal ice motion is crucial to ice dynamics of ice sheets. The classic Weertman model for basal sliding over bedrock obstacles proposes that sliding velocity is controlled by pressure melting and/or ductile flow, whichever is the fastest; it further assumes that pressure melting is limited by heat f...
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Copernicus Publications
2016
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fttriple:oai:gotriple.eu:oai:doaj.org/article:f0652c4a132542eab4ec64cd8a0ddd35 2023-05-15T16:29:26+02:00 Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming M. Krabbendam 2016-09-01 https://doi.org/10.5194/tc-10-1915-2016 https://www.the-cryosphere.net/10/1915/2016/tc-10-1915-2016.pdf https://doaj.org/article/f0652c4a132542eab4ec64cd8a0ddd35 en eng Copernicus Publications doi:10.5194/tc-10-1915-2016 1994-0416 1994-0424 https://www.the-cryosphere.net/10/1915/2016/tc-10-1915-2016.pdf https://doaj.org/article/f0652c4a132542eab4ec64cd8a0ddd35 undefined The Cryosphere, Vol 10, Pp 1915-1932 (2016) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2016 fttriple https://doi.org/10.5194/tc-10-1915-2016 2023-01-22T19:35:01Z Basal ice motion is crucial to ice dynamics of ice sheets. The classic Weertman model for basal sliding over bedrock obstacles proposes that sliding velocity is controlled by pressure melting and/or ductile flow, whichever is the fastest; it further assumes that pressure melting is limited by heat flow through the obstacle and ductile flow is controlled by standard power-law creep. These last two assumptions, however, are not applicable if a substantial basal layer of temperate (T ∼ Tmelt) ice is present. In that case, frictional melting can produce excess basal meltwater and efficient water flow, leading to near-thermal equilibrium. High-temperature ice creep experiments have shown a sharp weakening of a factor 5–10 close to Tmelt, suggesting standard power-law creep does not operate due to a switch to melt-assisted creep with a possible component of grain boundary melting. Pressure melting is controlled by meltwater production, heat advection by flowing meltwater to the next obstacle and heat conduction through ice/rock over half the obstacle height. No heat flow through the obstacle is required. Ice streaming over a rough, hard bed, as possibly in the Northeast Greenland Ice Stream, may be explained by enhanced basal motion in a thick temperate ice layer. Article in Journal/Newspaper Greenland The Cryosphere Unknown Greenland Weertman ENVELOPE(-67.753,-67.753,-66.972,-66.972) The Cryosphere 10 5 1915 1932 |
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English |
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geo envir |
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geo envir M. Krabbendam Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
topic_facet |
geo envir |
description |
Basal ice motion is crucial to ice dynamics of ice sheets. The classic Weertman model for basal sliding over bedrock obstacles proposes that sliding velocity is controlled by pressure melting and/or ductile flow, whichever is the fastest; it further assumes that pressure melting is limited by heat flow through the obstacle and ductile flow is controlled by standard power-law creep. These last two assumptions, however, are not applicable if a substantial basal layer of temperate (T ∼ Tmelt) ice is present. In that case, frictional melting can produce excess basal meltwater and efficient water flow, leading to near-thermal equilibrium. High-temperature ice creep experiments have shown a sharp weakening of a factor 5–10 close to Tmelt, suggesting standard power-law creep does not operate due to a switch to melt-assisted creep with a possible component of grain boundary melting. Pressure melting is controlled by meltwater production, heat advection by flowing meltwater to the next obstacle and heat conduction through ice/rock over half the obstacle height. No heat flow through the obstacle is required. Ice streaming over a rough, hard bed, as possibly in the Northeast Greenland Ice Stream, may be explained by enhanced basal motion in a thick temperate ice layer. |
format |
Article in Journal/Newspaper |
author |
M. Krabbendam |
author_facet |
M. Krabbendam |
author_sort |
M. Krabbendam |
title |
Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
title_short |
Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
title_full |
Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
title_fullStr |
Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
title_full_unstemmed |
Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
title_sort |
sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/tc-10-1915-2016 https://www.the-cryosphere.net/10/1915/2016/tc-10-1915-2016.pdf https://doaj.org/article/f0652c4a132542eab4ec64cd8a0ddd35 |
long_lat |
ENVELOPE(-67.753,-67.753,-66.972,-66.972) |
geographic |
Greenland Weertman |
geographic_facet |
Greenland Weertman |
genre |
Greenland The Cryosphere |
genre_facet |
Greenland The Cryosphere |
op_source |
The Cryosphere, Vol 10, Pp 1915-1932 (2016) |
op_relation |
doi:10.5194/tc-10-1915-2016 1994-0416 1994-0424 https://www.the-cryosphere.net/10/1915/2016/tc-10-1915-2016.pdf https://doaj.org/article/f0652c4a132542eab4ec64cd8a0ddd35 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-10-1915-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
5 |
container_start_page |
1915 |
op_container_end_page |
1932 |
_version_ |
1766019125242494976 |