Drumlin formation: a time transgressive model
Graphical and numerical reconstructions of the Rainy and Superior lobes of the Laurentide Ice Sheet suggest that drumlin formation was time transgressive. Suites of glacial landforms including drumlins, tunnel valleys, eskers, and ice‐collapse features can be correlated with specific recessional ice...
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crwiley:10.1111/j.1502-3885.1989.tb00379.x 2024-06-02T08:08:17+00:00 Drumlin formation: a time transgressive model MOOERS, HOWARD D. 1989 http://dx.doi.org/10.1111/j.1502-3885.1989.tb00379.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.1989.tb00379.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.1989.tb00379.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Boreas volume 18, issue 2, page 99-107 ISSN 0300-9483 1502-3885 journal-article 1989 crwiley https://doi.org/10.1111/j.1502-3885.1989.tb00379.x 2024-05-03T12:05:54Z Graphical and numerical reconstructions of the Rainy and Superior lobes of the Laurentide Ice Sheet suggest that drumlin formation was time transgressive. Suites of glacial landforms including drumlins, tunnel valleys, eskers, and ice‐collapse features can be correlated with specific recessional ice margins and are used as boundary conditions in the modeling. A contour map of the ice surface is then drawn using a specified basal shear stress. The shear stress can be constant or allowed to vary with position on the bed and is chosen to be consistent with the subglacial regime indicated by field evidence. Assuming that ice flow is parallel to drumlin orientations and perpendicular to the ice surface contours and moraines, the trend of drumlin axes is best accommodated by time transgressive drumlin formation during minor stillstands in the overall ice recession. The alternative, that drumlins were formed while the ice was at the Late Wisconsin maximum limit, requires large spatial variations in the basal shear stress distribution and therefore implies large mass‐balance gradients or large variations in basal sliding velocities over small distances, for which there is little evidence. Article in Journal/Newspaper Ice Sheet Wiley Online Library Boreas 18 2 99 107 |
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Open Polar |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Graphical and numerical reconstructions of the Rainy and Superior lobes of the Laurentide Ice Sheet suggest that drumlin formation was time transgressive. Suites of glacial landforms including drumlins, tunnel valleys, eskers, and ice‐collapse features can be correlated with specific recessional ice margins and are used as boundary conditions in the modeling. A contour map of the ice surface is then drawn using a specified basal shear stress. The shear stress can be constant or allowed to vary with position on the bed and is chosen to be consistent with the subglacial regime indicated by field evidence. Assuming that ice flow is parallel to drumlin orientations and perpendicular to the ice surface contours and moraines, the trend of drumlin axes is best accommodated by time transgressive drumlin formation during minor stillstands in the overall ice recession. The alternative, that drumlins were formed while the ice was at the Late Wisconsin maximum limit, requires large spatial variations in the basal shear stress distribution and therefore implies large mass‐balance gradients or large variations in basal sliding velocities over small distances, for which there is little evidence. |
format |
Article in Journal/Newspaper |
author |
MOOERS, HOWARD D. |
spellingShingle |
MOOERS, HOWARD D. Drumlin formation: a time transgressive model |
author_facet |
MOOERS, HOWARD D. |
author_sort |
MOOERS, HOWARD D. |
title |
Drumlin formation: a time transgressive model |
title_short |
Drumlin formation: a time transgressive model |
title_full |
Drumlin formation: a time transgressive model |
title_fullStr |
Drumlin formation: a time transgressive model |
title_full_unstemmed |
Drumlin formation: a time transgressive model |
title_sort |
drumlin formation: a time transgressive model |
publisher |
Wiley |
publishDate |
1989 |
url |
http://dx.doi.org/10.1111/j.1502-3885.1989.tb00379.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.1989.tb00379.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.1989.tb00379.x |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Boreas volume 18, issue 2, page 99-107 ISSN 0300-9483 1502-3885 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1502-3885.1989.tb00379.x |
container_title |
Boreas |
container_volume |
18 |
container_issue |
2 |
container_start_page |
99 |
op_container_end_page |
107 |
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1800753490847334400 |