Tunnel channels and associated landforms, south-central Ontario: their implications for ice-sheet hydrology
The Peterborough–Trenton drumlin field and associated meltwater erosion marks (s-forms) were interpreted as the products of erosion by turbulent separated flows within a catastrophically released subglacial meltwater sheet, the Algonquin event. Recent theoretical modelling of ice-sheet hydrology sug...
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Online Access: | http://dx.doi.org/10.1139/e94-045 http://www.nrcresearchpress.com/doi/pdf/10.1139/e94-045 |
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crcansciencepubl:10.1139/e94-045 2024-04-07T07:53:14+00:00 Tunnel channels and associated landforms, south-central Ontario: their implications for ice-sheet hydrology Brennand, Tracy A. Shaw, John 1994 http://dx.doi.org/10.1139/e94-045 http://www.nrcresearchpress.com/doi/pdf/10.1139/e94-045 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 31, issue 3, page 505-522 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1994 crcansciencepubl https://doi.org/10.1139/e94-045 2024-03-08T00:37:42Z The Peterborough–Trenton drumlin field and associated meltwater erosion marks (s-forms) were interpreted as the products of erosion by turbulent separated flows within a catastrophically released subglacial meltwater sheet, the Algonquin event. Recent theoretical modelling of ice-sheet hydrology suggests progressive channelization of meltwater during the collapse of such a sheet. Inductive testing of this hypothesis using observations in south-central Ontario forms the crux of this paper. A geometric model of the interaction of rough ice base and bed surfaces gives inferred meltwater flow patterns. Such a rough interactive geometry is suggested as the bed is drumlinized, and flows responsible for drumlins may be expected to have eroded similar forms into the ice base. Three landforms in south-central Ontario; namely tunnel channels, megachannels, and late-stage sheet-flow scours, are described, and interpreted as evidence of progressive channelization and flow diversion processes, governed by the geometric interactions between the recoupling ice base and its bed and thermodynamic feedbacks within an increasingly discontinuous meltwater sheet. Some fields of transverse ridges within tunnel channels may record meltwater deposition towards the end of the Algonquin event. By contrast, eskers within tunnel channels record a return to seasonally driven meltwater drainage. The Dummer Moraine and the Oak Ridges complex are integrated into a new landform–vent sequence for south-central Ontario which provides a framework for further field testing. Article in Journal/Newspaper Ice Sheet Canadian Science Publishing Canadian Journal of Earth Sciences 31 3 505 522 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
topic |
General Earth and Planetary Sciences |
spellingShingle |
General Earth and Planetary Sciences Brennand, Tracy A. Shaw, John Tunnel channels and associated landforms, south-central Ontario: their implications for ice-sheet hydrology |
topic_facet |
General Earth and Planetary Sciences |
description |
The Peterborough–Trenton drumlin field and associated meltwater erosion marks (s-forms) were interpreted as the products of erosion by turbulent separated flows within a catastrophically released subglacial meltwater sheet, the Algonquin event. Recent theoretical modelling of ice-sheet hydrology suggests progressive channelization of meltwater during the collapse of such a sheet. Inductive testing of this hypothesis using observations in south-central Ontario forms the crux of this paper. A geometric model of the interaction of rough ice base and bed surfaces gives inferred meltwater flow patterns. Such a rough interactive geometry is suggested as the bed is drumlinized, and flows responsible for drumlins may be expected to have eroded similar forms into the ice base. Three landforms in south-central Ontario; namely tunnel channels, megachannels, and late-stage sheet-flow scours, are described, and interpreted as evidence of progressive channelization and flow diversion processes, governed by the geometric interactions between the recoupling ice base and its bed and thermodynamic feedbacks within an increasingly discontinuous meltwater sheet. Some fields of transverse ridges within tunnel channels may record meltwater deposition towards the end of the Algonquin event. By contrast, eskers within tunnel channels record a return to seasonally driven meltwater drainage. The Dummer Moraine and the Oak Ridges complex are integrated into a new landform–vent sequence for south-central Ontario which provides a framework for further field testing. |
format |
Article in Journal/Newspaper |
author |
Brennand, Tracy A. Shaw, John |
author_facet |
Brennand, Tracy A. Shaw, John |
author_sort |
Brennand, Tracy A. |
title |
Tunnel channels and associated landforms, south-central Ontario: their implications for ice-sheet hydrology |
title_short |
Tunnel channels and associated landforms, south-central Ontario: their implications for ice-sheet hydrology |
title_full |
Tunnel channels and associated landforms, south-central Ontario: their implications for ice-sheet hydrology |
title_fullStr |
Tunnel channels and associated landforms, south-central Ontario: their implications for ice-sheet hydrology |
title_full_unstemmed |
Tunnel channels and associated landforms, south-central Ontario: their implications for ice-sheet hydrology |
title_sort |
tunnel channels and associated landforms, south-central ontario: their implications for ice-sheet hydrology |
publisher |
Canadian Science Publishing |
publishDate |
1994 |
url |
http://dx.doi.org/10.1139/e94-045 http://www.nrcresearchpress.com/doi/pdf/10.1139/e94-045 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Canadian Journal of Earth Sciences volume 31, issue 3, page 505-522 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e94-045 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
31 |
container_issue |
3 |
container_start_page |
505 |
op_container_end_page |
522 |
_version_ |
1795668914543263744 |