Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream
A grid of seismic reflection lines has been used to image basal topography and infer basal conditions and flow processes beneath similar to 140 km(2) of Rutford Ice Stream, West Antarctica. The subglacial topography in this region consists of two troughs flanking a central high and the bed is compos...
Published in: | Quaternary Science Reviews |
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Elsevier
2009
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ftnerc:oai:nora.nerc.ac.uk:11283 2023-05-15T13:45:10+02:00 Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream Smith, Andy M. Murray, Tavi 2009 http://nora.nerc.ac.uk/id/eprint/11283/ http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=1538169957&_sort=r&_st=13&view=c&_acct=C000054485&_version=1&_urlVersion=0&_userid=1773399&md5=dcd70dd1f3a007cff63cf8f9848d21ac&searchtype=a unknown Elsevier Smith, Andy M. orcid:0000-0001-8577-482X Murray, Tavi. 2009 Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream. Quaternary Science Reviews, 28 (7-8). 584-596. https://doi.org/10.1016/j.quascirev.2008.05.010 <https://doi.org/10.1016/j.quascirev.2008.05.010> Marine Sciences Glaciology Hydrology Earth Sciences Publication - Article PeerReviewed 2009 ftnerc https://doi.org/10.1016/j.quascirev.2008.05.010 2023-02-04T19:27:17Z A grid of seismic reflection lines has been used to image basal topography and infer basal conditions and flow processes beneath similar to 140 km(2) of Rutford Ice Stream, West Antarctica. The subglacial topography in this region consists of two troughs flanking a central high and the bed is composed of water-saturated sediments. The two troughs are filled with deforming sediment, whereas the bed in the central region appears to undergo a transition from largely deforming conditions upstream to basal sliding downstream. The deforming bed is very flat along flow, but undulates across flow. Sliding areas show rougher bed topography. Cross-stream bed topography is characterised by streamlined mounds of deforming sediment aligned in the ice flow direction. These bedforms occur superimposed on the bed in regions of both basal sliding and sediment deformation. In places, they form finger-like mounds of material, which extend into the sliding region further downstream. Mean bedform height is 22 m, mean width is 267 m, and many of them extend for at least 1-2 km along flow. We interpret most of these bedforms as drumlins and one as a mega-scale glacial lineation. The juxtaposition of different basal conditions is consistent with models proposed from terrestrial studies in which the glacier bed is a mosaic of stable and deforming bed areas, variable both spatially and temporally. Any theory of subglacial sediment rheology must also be able to account for our conclusion that, at any given time, pervasive deformation extends at least a few metres into the bed and can persist over a considerable area (many km(2)). Bedform geometry and basal conditions concur with interpretations of former ice streams, with evidence for increasing elongation ratio with distance downstream. However, those studies also identified bedrock cropping out at the ice-bed interface, for which there is no evidence on Rutford Ice Stream. (C) 2008 Elsevier Ltd. All rights reserved. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Stream C Rutford Ice Stream West Antarctica Natural Environment Research Council: NERC Open Research Archive Antarctic West Antarctica Rutford ENVELOPE(-85.300,-85.300,-78.600,-78.600) Rutford Ice Stream ENVELOPE(-80.000,-80.000,-79.167,-79.167) Quaternary Science Reviews 28 7-8 584 596 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Marine Sciences Glaciology Hydrology Earth Sciences |
spellingShingle |
Marine Sciences Glaciology Hydrology Earth Sciences Smith, Andy M. Murray, Tavi Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream |
topic_facet |
Marine Sciences Glaciology Hydrology Earth Sciences |
description |
A grid of seismic reflection lines has been used to image basal topography and infer basal conditions and flow processes beneath similar to 140 km(2) of Rutford Ice Stream, West Antarctica. The subglacial topography in this region consists of two troughs flanking a central high and the bed is composed of water-saturated sediments. The two troughs are filled with deforming sediment, whereas the bed in the central region appears to undergo a transition from largely deforming conditions upstream to basal sliding downstream. The deforming bed is very flat along flow, but undulates across flow. Sliding areas show rougher bed topography. Cross-stream bed topography is characterised by streamlined mounds of deforming sediment aligned in the ice flow direction. These bedforms occur superimposed on the bed in regions of both basal sliding and sediment deformation. In places, they form finger-like mounds of material, which extend into the sliding region further downstream. Mean bedform height is 22 m, mean width is 267 m, and many of them extend for at least 1-2 km along flow. We interpret most of these bedforms as drumlins and one as a mega-scale glacial lineation. The juxtaposition of different basal conditions is consistent with models proposed from terrestrial studies in which the glacier bed is a mosaic of stable and deforming bed areas, variable both spatially and temporally. Any theory of subglacial sediment rheology must also be able to account for our conclusion that, at any given time, pervasive deformation extends at least a few metres into the bed and can persist over a considerable area (many km(2)). Bedform geometry and basal conditions concur with interpretations of former ice streams, with evidence for increasing elongation ratio with distance downstream. However, those studies also identified bedrock cropping out at the ice-bed interface, for which there is no evidence on Rutford Ice Stream. (C) 2008 Elsevier Ltd. All rights reserved. |
format |
Article in Journal/Newspaper |
author |
Smith, Andy M. Murray, Tavi |
author_facet |
Smith, Andy M. Murray, Tavi |
author_sort |
Smith, Andy M. |
title |
Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream |
title_short |
Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream |
title_full |
Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream |
title_fullStr |
Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream |
title_full_unstemmed |
Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream |
title_sort |
bedform topography and basal conditions beneath a fast-flowing west antarctic ice stream |
publisher |
Elsevier |
publishDate |
2009 |
url |
http://nora.nerc.ac.uk/id/eprint/11283/ http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=1538169957&_sort=r&_st=13&view=c&_acct=C000054485&_version=1&_urlVersion=0&_userid=1773399&md5=dcd70dd1f3a007cff63cf8f9848d21ac&searchtype=a |
long_lat |
ENVELOPE(-85.300,-85.300,-78.600,-78.600) ENVELOPE(-80.000,-80.000,-79.167,-79.167) |
geographic |
Antarctic West Antarctica Rutford Rutford Ice Stream |
geographic_facet |
Antarctic West Antarctica Rutford Rutford Ice Stream |
genre |
Antarc* Antarctic Antarctica Ice Stream C Rutford Ice Stream West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Ice Stream C Rutford Ice Stream West Antarctica |
op_relation |
Smith, Andy M. orcid:0000-0001-8577-482X Murray, Tavi. 2009 Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream. Quaternary Science Reviews, 28 (7-8). 584-596. https://doi.org/10.1016/j.quascirev.2008.05.010 <https://doi.org/10.1016/j.quascirev.2008.05.010> |
op_doi |
https://doi.org/10.1016/j.quascirev.2008.05.010 |
container_title |
Quaternary Science Reviews |
container_volume |
28 |
container_issue |
7-8 |
container_start_page |
584 |
op_container_end_page |
596 |
_version_ |
1766214464921665536 |