Thermal Conditions at the Bed of the Laurentide Ice Sheet in Maine During Deglaciation: Implications for Esker Formation
The University of Maine Ice Sheet Model was used to study basal conditions during retreat of the Laurentide ice sheet in Maine. Within 150 km of the margin, basal melt rates average similar to 5 mm a(-1) during retreat. They decline over the next 100km, so areas of frozen bed develop in northern Mai...
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ftmaineuniv:oai:digitalcommons.library.umaine.edu:ers_facpub-1107 2023-05-15T16:40:18+02:00 Thermal Conditions at the Bed of the Laurentide Ice Sheet in Maine During Deglaciation: Implications for Esker Formation Hooke, Roger Fastook, James 2007-01-01T08:00:00Z application/pdf https://digitalcommons.library.umaine.edu/ers_facpub/108 https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1107&context=ers_facpub unknown DigitalCommons@UMaine https://digitalcommons.library.umaine.edu/ers_facpub/108 https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1107&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 2007 ftmaineuniv 2023-03-12T18:54:03Z The University of Maine Ice Sheet Model was used to study basal conditions during retreat of the Laurentide ice sheet in Maine. Within 150 km of the margin, basal melt rates average similar to 5 mm a(-1) during retreat. They decline over the next 100km, so areas of frozen bed develop in northern Maine during retreat. By integrating the melt rate over the drainage area typically subtended by an esker, we obtained a discharge at the margin of similar to 1.2 m(3) s(-1). While such a discharge could have moved the material in the Katahdin esker, it was likely too low to build the esker in the time available. Additional water from the glacier surface was required. Temperature gradients in the basal ice increase rapidly with distance from the margin. By conducting upward into the ice all of the additional viscous heat produced by any perturbation that increases the depth of flow in a flat conduit in a distributed drainage system, these gradients inhibit the formation of sharply arched conduits in which an esker can form. This may explain why eskers commonly seem to form near the margin and are typically segmented, with later segments overlapping onto earlier ones. Text Ice Sheet The University of Maine: DigitalCommons@UMaine |
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The University of Maine: DigitalCommons@UMaine |
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Earth Sciences |
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Earth Sciences Hooke, Roger Fastook, James Thermal Conditions at the Bed of the Laurentide Ice Sheet in Maine During Deglaciation: Implications for Esker Formation |
topic_facet |
Earth Sciences |
description |
The University of Maine Ice Sheet Model was used to study basal conditions during retreat of the Laurentide ice sheet in Maine. Within 150 km of the margin, basal melt rates average similar to 5 mm a(-1) during retreat. They decline over the next 100km, so areas of frozen bed develop in northern Maine during retreat. By integrating the melt rate over the drainage area typically subtended by an esker, we obtained a discharge at the margin of similar to 1.2 m(3) s(-1). While such a discharge could have moved the material in the Katahdin esker, it was likely too low to build the esker in the time available. Additional water from the glacier surface was required. Temperature gradients in the basal ice increase rapidly with distance from the margin. By conducting upward into the ice all of the additional viscous heat produced by any perturbation that increases the depth of flow in a flat conduit in a distributed drainage system, these gradients inhibit the formation of sharply arched conduits in which an esker can form. This may explain why eskers commonly seem to form near the margin and are typically segmented, with later segments overlapping onto earlier ones. |
format |
Text |
author |
Hooke, Roger Fastook, James |
author_facet |
Hooke, Roger Fastook, James |
author_sort |
Hooke, Roger |
title |
Thermal Conditions at the Bed of the Laurentide Ice Sheet in Maine During Deglaciation: Implications for Esker Formation |
title_short |
Thermal Conditions at the Bed of the Laurentide Ice Sheet in Maine During Deglaciation: Implications for Esker Formation |
title_full |
Thermal Conditions at the Bed of the Laurentide Ice Sheet in Maine During Deglaciation: Implications for Esker Formation |
title_fullStr |
Thermal Conditions at the Bed of the Laurentide Ice Sheet in Maine During Deglaciation: Implications for Esker Formation |
title_full_unstemmed |
Thermal Conditions at the Bed of the Laurentide Ice Sheet in Maine During Deglaciation: Implications for Esker Formation |
title_sort |
thermal conditions at the bed of the laurentide ice sheet in maine during deglaciation: implications for esker formation |
publisher |
DigitalCommons@UMaine |
publishDate |
2007 |
url |
https://digitalcommons.library.umaine.edu/ers_facpub/108 https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1107&context=ers_facpub |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Earth Science Faculty Scholarship |
op_relation |
https://digitalcommons.library.umaine.edu/ers_facpub/108 https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1107&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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1766030681484296192 |