Bedrock erosion in subglacial channels
The Labyrinth in the McMurdo Dry Valleys of Antarctica is characterized by large bedrock channels emerging from beneath the margin of Wright Upper Glacier. To study the morphodynamics of large subglacial channels cut into bedrock, we develop herein a numerical model based on the classical theory of...
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ftpubmed:oai:pubmedcentral.nih.gov:8428685 2023-05-15T13:47:21+02:00 Bedrock erosion in subglacial channels Fagherazzi, Sergio Baticci, Luca Brandon, Christine M. Rulli, Maria Cristina 2021-09-09 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8428685/ https://doi.org/10.1371/journal.pone.0253768 en eng Public Library of Science http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8428685/ http://dx.doi.org/10.1371/journal.pone.0253768 © 2021 Fagherazzi et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. CC-BY PLoS One Research Article Text 2021 ftpubmed https://doi.org/10.1371/journal.pone.0253768 2021-09-12T00:48:52Z The Labyrinth in the McMurdo Dry Valleys of Antarctica is characterized by large bedrock channels emerging from beneath the margin of Wright Upper Glacier. To study the morphodynamics of large subglacial channels cut into bedrock, we develop herein a numerical model based on the classical theory of subglacial channels and recent results on bedrock abrasion by saltating bed load. Model results show that bedrock abrasion in subglacial channels with pressurized flow reaches a maximum at an intermediate distance up-ice from the glacier snout for a wide range of sediment grain sizes and sediment loads. Close to the snout, the velocity is too low and the sediment particles cannot be mobilized. Far from the snout, the flow accelerates and sediment is transported in suspension, thus limiting particle impacts at the channel bottom and reducing abrasion. This non-monotonic relationship between subglacial flow and bedrock abrasion produces concave up bottom profiles in subglacial channels and potential cross-section constrictions after channel confluences. Both landforms are present in the bedrock channels of the Labyrinth. We therefore conclude that these geomorphic features are a possible signature of bedrock abrasion, rather than glacial scour, and reflect the complex interplay between transport rate, sediment load, and transport capacity in subglacial channels. Text Antarc* Antarctica McMurdo Dry Valleys PubMed Central (PMC) Labyrinth ENVELOPE(160.833,160.833,-77.550,-77.550) McMurdo Dry Valleys Wright Upper Glacier ENVELOPE(160.583,160.583,-77.533,-77.533) PLOS ONE 16 9 e0253768 |
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English |
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Research Article |
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Research Article Fagherazzi, Sergio Baticci, Luca Brandon, Christine M. Rulli, Maria Cristina Bedrock erosion in subglacial channels |
topic_facet |
Research Article |
description |
The Labyrinth in the McMurdo Dry Valleys of Antarctica is characterized by large bedrock channels emerging from beneath the margin of Wright Upper Glacier. To study the morphodynamics of large subglacial channels cut into bedrock, we develop herein a numerical model based on the classical theory of subglacial channels and recent results on bedrock abrasion by saltating bed load. Model results show that bedrock abrasion in subglacial channels with pressurized flow reaches a maximum at an intermediate distance up-ice from the glacier snout for a wide range of sediment grain sizes and sediment loads. Close to the snout, the velocity is too low and the sediment particles cannot be mobilized. Far from the snout, the flow accelerates and sediment is transported in suspension, thus limiting particle impacts at the channel bottom and reducing abrasion. This non-monotonic relationship between subglacial flow and bedrock abrasion produces concave up bottom profiles in subglacial channels and potential cross-section constrictions after channel confluences. Both landforms are present in the bedrock channels of the Labyrinth. We therefore conclude that these geomorphic features are a possible signature of bedrock abrasion, rather than glacial scour, and reflect the complex interplay between transport rate, sediment load, and transport capacity in subglacial channels. |
format |
Text |
author |
Fagherazzi, Sergio Baticci, Luca Brandon, Christine M. Rulli, Maria Cristina |
author_facet |
Fagherazzi, Sergio Baticci, Luca Brandon, Christine M. Rulli, Maria Cristina |
author_sort |
Fagherazzi, Sergio |
title |
Bedrock erosion in subglacial channels |
title_short |
Bedrock erosion in subglacial channels |
title_full |
Bedrock erosion in subglacial channels |
title_fullStr |
Bedrock erosion in subglacial channels |
title_full_unstemmed |
Bedrock erosion in subglacial channels |
title_sort |
bedrock erosion in subglacial channels |
publisher |
Public Library of Science |
publishDate |
2021 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8428685/ https://doi.org/10.1371/journal.pone.0253768 |
long_lat |
ENVELOPE(160.833,160.833,-77.550,-77.550) ENVELOPE(160.583,160.583,-77.533,-77.533) |
geographic |
Labyrinth McMurdo Dry Valleys Wright Upper Glacier |
geographic_facet |
Labyrinth McMurdo Dry Valleys Wright Upper Glacier |
genre |
Antarc* Antarctica McMurdo Dry Valleys |
genre_facet |
Antarc* Antarctica McMurdo Dry Valleys |
op_source |
PLoS One |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8428685/ http://dx.doi.org/10.1371/journal.pone.0253768 |
op_rights |
© 2021 Fagherazzi et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1371/journal.pone.0253768 |
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PLOS ONE |
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16 |
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9 |
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e0253768 |
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