Evidence for catastrophic subglacial meltwater sheetflood events on the Bruce Peninsula, Ontario
The Bruce Peninsula, a carbonate bedrock escarpment, lies "downflow" from a sculpted bedrock terrain at the French River. The sculpted forms are attributed to a hypothesis of erosion by regional-scale, subglacial meltwater flooding. This paper presents new data from the Bruce Peninsula tha...
Published in: | Canadian Journal of Earth Sciences |
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Language: | English |
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1998
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Online Access: | http://dx.doi.org/10.1139/e98-067 http://www.nrcresearchpress.com/doi/pdf/10.1139/e98-067 |
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crcansciencepubl:10.1139/e98-067 2024-09-15T18:12:31+00:00 Evidence for catastrophic subglacial meltwater sheetflood events on the Bruce Peninsula, Ontario Kor, PSG Cowell, D W 1998 http://dx.doi.org/10.1139/e98-067 http://www.nrcresearchpress.com/doi/pdf/10.1139/e98-067 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 35, issue 10, page 1180-1202 ISSN 0008-4077 1480-3313 journal-article 1998 crcansciencepubl https://doi.org/10.1139/e98-067 2024-07-25T04:10:08Z The Bruce Peninsula, a carbonate bedrock escarpment, lies "downflow" from a sculpted bedrock terrain at the French River. The sculpted forms are attributed to a hypothesis of erosion by regional-scale, subglacial meltwater flooding. This paper presents new data from the Bruce Peninsula that tests the meltwater outburst hypothesis in a downflow direction of the predicted flood path. The bedrock surface of the Bruce Peninsula shows extensive development of sculpted features that bear a striking resemblance to s-forms at the mouth of the French River. They are self-similar and hierarchical in scale, ranging in dimensions from a few centimetres to several kilometres. Remarkable concentrations of potholes are located near the brow of the escarpment. The Bruce Peninsula lacks a pervasive cover of unconsolidated sediment. What little sediment exists has been modified into long, narrow drumlins. The Niagara Escarpment on the peninsula has been back wasted into the edge of the Paleozoic Michigan Basin. Along its east-facing slope, the escarpment is marked by more overdeepened reentrant valleys and intervening promontories than is normal for the rest of the escarpment. Clusters of rounded, percussion-marked boulders of exotic origin are concentrated at the heads of the reentrant valleys. Taken together, these features are inferred to support the hypothesis that subglacial outburst floods beneath the Laurentide ice sheet crossed Georgian Bay and strongly sculpted the Bruce Peninsula. The consistent orientation of the reentrant valleys, aligned with the French River sculpting across the basin to the northeast, and the backwasting of its caprock attest to the power and directional stability of the sheetfloods. Article in Journal/Newspaper Ice Sheet Canadian Science Publishing Canadian Journal of Earth Sciences 35 10 1180 1202 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
The Bruce Peninsula, a carbonate bedrock escarpment, lies "downflow" from a sculpted bedrock terrain at the French River. The sculpted forms are attributed to a hypothesis of erosion by regional-scale, subglacial meltwater flooding. This paper presents new data from the Bruce Peninsula that tests the meltwater outburst hypothesis in a downflow direction of the predicted flood path. The bedrock surface of the Bruce Peninsula shows extensive development of sculpted features that bear a striking resemblance to s-forms at the mouth of the French River. They are self-similar and hierarchical in scale, ranging in dimensions from a few centimetres to several kilometres. Remarkable concentrations of potholes are located near the brow of the escarpment. The Bruce Peninsula lacks a pervasive cover of unconsolidated sediment. What little sediment exists has been modified into long, narrow drumlins. The Niagara Escarpment on the peninsula has been back wasted into the edge of the Paleozoic Michigan Basin. Along its east-facing slope, the escarpment is marked by more overdeepened reentrant valleys and intervening promontories than is normal for the rest of the escarpment. Clusters of rounded, percussion-marked boulders of exotic origin are concentrated at the heads of the reentrant valleys. Taken together, these features are inferred to support the hypothesis that subglacial outburst floods beneath the Laurentide ice sheet crossed Georgian Bay and strongly sculpted the Bruce Peninsula. The consistent orientation of the reentrant valleys, aligned with the French River sculpting across the basin to the northeast, and the backwasting of its caprock attest to the power and directional stability of the sheetfloods. |
format |
Article in Journal/Newspaper |
author |
Kor, PSG Cowell, D W |
spellingShingle |
Kor, PSG Cowell, D W Evidence for catastrophic subglacial meltwater sheetflood events on the Bruce Peninsula, Ontario |
author_facet |
Kor, PSG Cowell, D W |
author_sort |
Kor, PSG |
title |
Evidence for catastrophic subglacial meltwater sheetflood events on the Bruce Peninsula, Ontario |
title_short |
Evidence for catastrophic subglacial meltwater sheetflood events on the Bruce Peninsula, Ontario |
title_full |
Evidence for catastrophic subglacial meltwater sheetflood events on the Bruce Peninsula, Ontario |
title_fullStr |
Evidence for catastrophic subglacial meltwater sheetflood events on the Bruce Peninsula, Ontario |
title_full_unstemmed |
Evidence for catastrophic subglacial meltwater sheetflood events on the Bruce Peninsula, Ontario |
title_sort |
evidence for catastrophic subglacial meltwater sheetflood events on the bruce peninsula, ontario |
publisher |
Canadian Science Publishing |
publishDate |
1998 |
url |
http://dx.doi.org/10.1139/e98-067 http://www.nrcresearchpress.com/doi/pdf/10.1139/e98-067 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Canadian Journal of Earth Sciences volume 35, issue 10, page 1180-1202 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e98-067 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
35 |
container_issue |
10 |
container_start_page |
1180 |
op_container_end_page |
1202 |
_version_ |
1810450100455997440 |