Geomorphic signature of Antarctic submarine gullies: Implications for continental slope processes
Five quantitatively distinct gully types are identified on the Antarctic continental margin from swath bathymetric data of over 1100 individual features. The gullies differ in terms of length, width, depth, width/depth ratio, cross-sectional shape, branching order, sinuosity and spatial density. Qua...
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Online Access: | https://research.manchester.ac.uk/en/publications/c23f3017-9fdd-4bc4-8beb-dbdb16ac13c0 https://doi.org/10.1016/j.margeo.2013.02.003 |
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ftumanchesterpub:oai:pure.atira.dk:publications/c23f3017-9fdd-4bc4-8beb-dbdb16ac13c0 2023-11-12T04:08:31+01:00 Geomorphic signature of Antarctic submarine gullies: Implications for continental slope processes Gales, Jennifer A. Larter, Robert D. Mitchell, Neil C. Dowdeswell, Julian A. 2013-03-01 https://research.manchester.ac.uk/en/publications/c23f3017-9fdd-4bc4-8beb-dbdb16ac13c0 https://doi.org/10.1016/j.margeo.2013.02.003 eng eng info:eu-repo/semantics/closedAccess Gales , J A , Larter , R D , Mitchell , N C & Dowdeswell , J A 2013 , ' Geomorphic signature of Antarctic submarine gullies: Implications for continental slope processes ' , Marine Geology , vol. 337 , pp. 112-124 . https://doi.org/10.1016/j.margeo.2013.02.003 Antarctica Continental margin Geomorphology Subglacial meltwater Submarine gully article 2013 ftumanchesterpub https://doi.org/10.1016/j.margeo.2013.02.003 2023-10-30T09:12:37Z Five quantitatively distinct gully types are identified on the Antarctic continental margin from swath bathymetric data of over 1100 individual features. The gullies differ in terms of length, width, depth, width/depth ratio, cross-sectional shape, branching order, sinuosity and spatial density. Quantitative analysis suggests that Antarctic gully morphology varies with local slope character (i.e. slope geometry, gradient), regional factors (i.e. location of cross-shelf troughs, trough mouth fans, subglacial meltwater production rates, drainage basin size), sediment yield and ice-sheet history. In keeping with interpretations of previous researchers, most gullies are probably formed by hyperpycnal flows of sediment-laden subglacial meltwater released from beneath ice-sheets grounded at the continental shelf edge during glacial maxima. The limited down-slope extent of gullies on the western Antarctic Peninsula is explained by the steep gradient and slope geometry at the mouth of Marguerite Trough, which cause flows to accelerate and entrain seawater more quickly, resulting in a reduction of the negative buoyancy effect of the sediment load. Due to pressure gradients at the ice-sheet bed caused by variations in ice thickness inside and outside palaeo-ice stream troughs, subglacial meltwater flow was generally focussed towards trough margins. This has resulted in gullies with larger cross-sectional areas and higher sinuosities at the trough margins. A unique style of gullying is observed off one part of the western Antarctic Peninsula, corresponding to an area in which the ice-sheet grounding line is not thought to have reached the shelf edge during the Last Glacial Maximum. We interpret the features in this area as the cumulative result of slope processes that operated over a long period of time in the absence of hyperpycnal meltwater flows. © 2013 Elsevier B.V. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Antarctica Ice Sheet The University of Manchester: Research Explorer Antarctic Antarctic Peninsula Marguerite ENVELOPE(141.378,141.378,-66.787,-66.787) The Antarctic Marine Geology 337 112 124 |
institution |
Open Polar |
collection |
The University of Manchester: Research Explorer |
op_collection_id |
ftumanchesterpub |
language |
English |
topic |
Antarctica Continental margin Geomorphology Subglacial meltwater Submarine gully |
spellingShingle |
Antarctica Continental margin Geomorphology Subglacial meltwater Submarine gully Gales, Jennifer A. Larter, Robert D. Mitchell, Neil C. Dowdeswell, Julian A. Geomorphic signature of Antarctic submarine gullies: Implications for continental slope processes |
topic_facet |
Antarctica Continental margin Geomorphology Subglacial meltwater Submarine gully |
description |
Five quantitatively distinct gully types are identified on the Antarctic continental margin from swath bathymetric data of over 1100 individual features. The gullies differ in terms of length, width, depth, width/depth ratio, cross-sectional shape, branching order, sinuosity and spatial density. Quantitative analysis suggests that Antarctic gully morphology varies with local slope character (i.e. slope geometry, gradient), regional factors (i.e. location of cross-shelf troughs, trough mouth fans, subglacial meltwater production rates, drainage basin size), sediment yield and ice-sheet history. In keeping with interpretations of previous researchers, most gullies are probably formed by hyperpycnal flows of sediment-laden subglacial meltwater released from beneath ice-sheets grounded at the continental shelf edge during glacial maxima. The limited down-slope extent of gullies on the western Antarctic Peninsula is explained by the steep gradient and slope geometry at the mouth of Marguerite Trough, which cause flows to accelerate and entrain seawater more quickly, resulting in a reduction of the negative buoyancy effect of the sediment load. Due to pressure gradients at the ice-sheet bed caused by variations in ice thickness inside and outside palaeo-ice stream troughs, subglacial meltwater flow was generally focussed towards trough margins. This has resulted in gullies with larger cross-sectional areas and higher sinuosities at the trough margins. A unique style of gullying is observed off one part of the western Antarctic Peninsula, corresponding to an area in which the ice-sheet grounding line is not thought to have reached the shelf edge during the Last Glacial Maximum. We interpret the features in this area as the cumulative result of slope processes that operated over a long period of time in the absence of hyperpycnal meltwater flows. © 2013 Elsevier B.V. |
format |
Article in Journal/Newspaper |
author |
Gales, Jennifer A. Larter, Robert D. Mitchell, Neil C. Dowdeswell, Julian A. |
author_facet |
Gales, Jennifer A. Larter, Robert D. Mitchell, Neil C. Dowdeswell, Julian A. |
author_sort |
Gales, Jennifer A. |
title |
Geomorphic signature of Antarctic submarine gullies: Implications for continental slope processes |
title_short |
Geomorphic signature of Antarctic submarine gullies: Implications for continental slope processes |
title_full |
Geomorphic signature of Antarctic submarine gullies: Implications for continental slope processes |
title_fullStr |
Geomorphic signature of Antarctic submarine gullies: Implications for continental slope processes |
title_full_unstemmed |
Geomorphic signature of Antarctic submarine gullies: Implications for continental slope processes |
title_sort |
geomorphic signature of antarctic submarine gullies: implications for continental slope processes |
publishDate |
2013 |
url |
https://research.manchester.ac.uk/en/publications/c23f3017-9fdd-4bc4-8beb-dbdb16ac13c0 https://doi.org/10.1016/j.margeo.2013.02.003 |
long_lat |
ENVELOPE(141.378,141.378,-66.787,-66.787) |
geographic |
Antarctic Antarctic Peninsula Marguerite The Antarctic |
geographic_facet |
Antarctic Antarctic Peninsula Marguerite The Antarctic |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Ice Sheet |
op_source |
Gales , J A , Larter , R D , Mitchell , N C & Dowdeswell , J A 2013 , ' Geomorphic signature of Antarctic submarine gullies: Implications for continental slope processes ' , Marine Geology , vol. 337 , pp. 112-124 . https://doi.org/10.1016/j.margeo.2013.02.003 |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.1016/j.margeo.2013.02.003 |
container_title |
Marine Geology |
container_volume |
337 |
container_start_page |
112 |
op_container_end_page |
124 |
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1782328798504550400 |