Modeling the deglaciation of the Green Bay Lobe of the southern Laurentide Ice Sheet
We use a time‐dependent two‐dimensional ice‐flow model to explore the development of the Green Bay Lobe, an outlet glacier of the southern Laurentide Ice Sheet, leading up to the time of maximum ice extent and during subsequent deglaciation (c. 30 to 8 cal. ka BP). We focus on conditions at the ice‐...
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crwiley:10.1111/j.1502-3885.2004.tb00994.x 2024-09-15T18:11:27+00:00 Modeling the deglaciation of the Green Bay Lobe of the southern Laurentide Ice Sheet WINGUTH, CORNELIA MICKELSON, DAVID M. COLGAN, PATRICK M. LAABS, BENJAMIN J. C. 2004 http://dx.doi.org/10.1111/j.1502-3885.2004.tb00994.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.2004.tb00994.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.2004.tb00994.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Boreas volume 33, issue 1, page 34-47 ISSN 0300-9483 1502-3885 journal-article 2004 crwiley https://doi.org/10.1111/j.1502-3885.2004.tb00994.x 2024-07-25T04:20:14Z We use a time‐dependent two‐dimensional ice‐flow model to explore the development of the Green Bay Lobe, an outlet glacier of the southern Laurentide Ice Sheet, leading up to the time of maximum ice extent and during subsequent deglaciation (c. 30 to 8 cal. ka BP). We focus on conditions at the ice‐bed interface in order to evaluate their possible impact on glacial landscape evolution. Air temperatures for model input have been reconstructed using the GRIP δ 8 O record calibrated to speleothem records from Missouri that cover the time periods of c . 65 to 30 cal. ka BP and 13.25 to 12.4 cal. ka BP. Using that input, the known ice extents during maximum glaciation and early deglaciation can be reproduced reasonably well. The model fails, however, to reproduce short‐term ice margin retreat and readvance events during later stages of deglaciation. Model results indicate that the area exposed after the retreat of the Green Bay Lobe was characterized by permafrost until at least 14 cal. ka BP. The extensive drumlin zones that formed behind the ice margins of the outermost Johnstown phase and the later Green Lake phase are associated with modeled ice margins that were stable for at least 1000 years, high basal shear stresses (c. 100 kPa) and permafrost depths of 80–200 m. During deglaciation, basal meltwater and sliding became more important. Article in Journal/Newspaper Ice Ice Sheet permafrost Wiley Online Library Boreas 33 1 34 47 |
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English |
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We use a time‐dependent two‐dimensional ice‐flow model to explore the development of the Green Bay Lobe, an outlet glacier of the southern Laurentide Ice Sheet, leading up to the time of maximum ice extent and during subsequent deglaciation (c. 30 to 8 cal. ka BP). We focus on conditions at the ice‐bed interface in order to evaluate their possible impact on glacial landscape evolution. Air temperatures for model input have been reconstructed using the GRIP δ 8 O record calibrated to speleothem records from Missouri that cover the time periods of c . 65 to 30 cal. ka BP and 13.25 to 12.4 cal. ka BP. Using that input, the known ice extents during maximum glaciation and early deglaciation can be reproduced reasonably well. The model fails, however, to reproduce short‐term ice margin retreat and readvance events during later stages of deglaciation. Model results indicate that the area exposed after the retreat of the Green Bay Lobe was characterized by permafrost until at least 14 cal. ka BP. The extensive drumlin zones that formed behind the ice margins of the outermost Johnstown phase and the later Green Lake phase are associated with modeled ice margins that were stable for at least 1000 years, high basal shear stresses (c. 100 kPa) and permafrost depths of 80–200 m. During deglaciation, basal meltwater and sliding became more important. |
format |
Article in Journal/Newspaper |
author |
WINGUTH, CORNELIA MICKELSON, DAVID M. COLGAN, PATRICK M. LAABS, BENJAMIN J. C. |
spellingShingle |
WINGUTH, CORNELIA MICKELSON, DAVID M. COLGAN, PATRICK M. LAABS, BENJAMIN J. C. Modeling the deglaciation of the Green Bay Lobe of the southern Laurentide Ice Sheet |
author_facet |
WINGUTH, CORNELIA MICKELSON, DAVID M. COLGAN, PATRICK M. LAABS, BENJAMIN J. C. |
author_sort |
WINGUTH, CORNELIA |
title |
Modeling the deglaciation of the Green Bay Lobe of the southern Laurentide Ice Sheet |
title_short |
Modeling the deglaciation of the Green Bay Lobe of the southern Laurentide Ice Sheet |
title_full |
Modeling the deglaciation of the Green Bay Lobe of the southern Laurentide Ice Sheet |
title_fullStr |
Modeling the deglaciation of the Green Bay Lobe of the southern Laurentide Ice Sheet |
title_full_unstemmed |
Modeling the deglaciation of the Green Bay Lobe of the southern Laurentide Ice Sheet |
title_sort |
modeling the deglaciation of the green bay lobe of the southern laurentide ice sheet |
publisher |
Wiley |
publishDate |
2004 |
url |
http://dx.doi.org/10.1111/j.1502-3885.2004.tb00994.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.2004.tb00994.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.2004.tb00994.x |
genre |
Ice Ice Sheet permafrost |
genre_facet |
Ice Ice Sheet permafrost |
op_source |
Boreas volume 33, issue 1, page 34-47 ISSN 0300-9483 1502-3885 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1502-3885.2004.tb00994.x |
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Boreas |
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33 |
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1 |
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34 |
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47 |
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1810449039324348416 |