Englacial stratigraphy, debris entrainment and ice sheet stability of Horseshoe Valley, West Antarctica
Despite the importance of ice streaming to the evaluation of West Antarctic Ice Sheet (WAIS) stability, we know little about mid-to long term changes in grounding line migration, ice streaming and ice accumulation in the upper Institute Ice Stream (IIS) catchment. In this thesis ground penetrating r...
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ftunivnorthumb:oai:nrl.northumbria.ac.uk:31620 2023-05-15T13:56:54+02:00 Englacial stratigraphy, debris entrainment and ice sheet stability of Horseshoe Valley, West Antarctica Winter, Kate 2016-10-01 text https://nrl.northumbria.ac.uk/id/eprint/31620/ https://nrl.northumbria.ac.uk/id/eprint/31620/1/winter.kate_phd.pdf en eng https://nrl.northumbria.ac.uk/id/eprint/31620/1/winter.kate_phd.pdf Winter, Kate (2016) Englacial stratigraphy, debris entrainment and ice sheet stability of Horseshoe Valley, West Antarctica. Doctoral thesis, Northumbria University. F600 Geology F800 Physical and Terrestrial Geographical and Environmental Sciences Thesis NonPeerReviewed 2016 ftunivnorthumb 2022-09-25T06:06:00Z Despite the importance of ice streaming to the evaluation of West Antarctic Ice Sheet (WAIS) stability, we know little about mid-to long term changes in grounding line migration, ice streaming and ice accumulation in the upper Institute Ice Stream (IIS) catchment. In this thesis ground penetrating radar (GPR) and airborne radio-echo sounding (RES) methods have been employed to investigate the subglacial topography, internal stratigraphy and Holocene flow regime of the upper IIS catchment, in and around Horseshoe Valley. High resolution step-andcollect mode GPR was employed to assess the continuity of a Blue Ice Area (BIA) horizontal ice core climate record at Patriot Hills, where analysis has revealed two unconformities in the otherwise conformable 30,000 year climate sequence. By combining these data with airborne RES returns and pre-existing ice sheet models it is suggested that these unconformities represent periods of erosion, occurring as the former ice surface was scoured by katabatic winds in front of Liberty and Mable Hills. Snow_Blow simulations suggest that katabatic winds have scoured the leeward slopes of these mountain ranges for over 10,000 years. This temporal stability can account for the large volume of BI moraine deposits in Horseshoe Valley, where compressive BI flows promote glacial erosion and near-surface debris entrainment through freeze-on processes at the ice/bed interface and compressive thrust faulting. By investigating thicker ice flows in the upper IIS catchment and the Evans Ice Stream, this thesis has also analysed debris entrainment mechanisms at depth, where clasts are incorporated into the ice flow by englacial stratigraphic folding and shearing at the glacial thermal boundary, governed by spatial and temporal changes in ice flow, ice temperature and sediment availability. Mid-to long term changes in ice flow in the wider IIS catchment have been investigated from airborne RES transects, revealing internal layer buckling, and therefore former enhanced ice-sheet flow in three ... Thesis Antarc* Antarctic Antarctica Evans Ice Stream ice core Ice Sheet Institute Ice Stream West Antarctica Northumbria University, Newcastle: Northumbria Research Link (NRL) Antarctic Bia ENVELOPE(22.891,22.891,70.317,70.317) Evans Ice Stream ENVELOPE(-78.000,-78.000,-76.000,-76.000) Horseshoe Valley ENVELOPE(-82.000,-82.000,-80.083,-80.083) Institute Ice Stream ENVELOPE(-75.000,-75.000,-82.000,-82.000) Patriot Hills ENVELOPE(-81.333,-81.333,-80.333,-80.333) West Antarctic Ice Sheet West Antarctica |
institution |
Open Polar |
collection |
Northumbria University, Newcastle: Northumbria Research Link (NRL) |
op_collection_id |
ftunivnorthumb |
language |
English |
topic |
F600 Geology F800 Physical and Terrestrial Geographical and Environmental Sciences |
spellingShingle |
F600 Geology F800 Physical and Terrestrial Geographical and Environmental Sciences Winter, Kate Englacial stratigraphy, debris entrainment and ice sheet stability of Horseshoe Valley, West Antarctica |
topic_facet |
F600 Geology F800 Physical and Terrestrial Geographical and Environmental Sciences |
description |
Despite the importance of ice streaming to the evaluation of West Antarctic Ice Sheet (WAIS) stability, we know little about mid-to long term changes in grounding line migration, ice streaming and ice accumulation in the upper Institute Ice Stream (IIS) catchment. In this thesis ground penetrating radar (GPR) and airborne radio-echo sounding (RES) methods have been employed to investigate the subglacial topography, internal stratigraphy and Holocene flow regime of the upper IIS catchment, in and around Horseshoe Valley. High resolution step-andcollect mode GPR was employed to assess the continuity of a Blue Ice Area (BIA) horizontal ice core climate record at Patriot Hills, where analysis has revealed two unconformities in the otherwise conformable 30,000 year climate sequence. By combining these data with airborne RES returns and pre-existing ice sheet models it is suggested that these unconformities represent periods of erosion, occurring as the former ice surface was scoured by katabatic winds in front of Liberty and Mable Hills. Snow_Blow simulations suggest that katabatic winds have scoured the leeward slopes of these mountain ranges for over 10,000 years. This temporal stability can account for the large volume of BI moraine deposits in Horseshoe Valley, where compressive BI flows promote glacial erosion and near-surface debris entrainment through freeze-on processes at the ice/bed interface and compressive thrust faulting. By investigating thicker ice flows in the upper IIS catchment and the Evans Ice Stream, this thesis has also analysed debris entrainment mechanisms at depth, where clasts are incorporated into the ice flow by englacial stratigraphic folding and shearing at the glacial thermal boundary, governed by spatial and temporal changes in ice flow, ice temperature and sediment availability. Mid-to long term changes in ice flow in the wider IIS catchment have been investigated from airborne RES transects, revealing internal layer buckling, and therefore former enhanced ice-sheet flow in three ... |
format |
Thesis |
author |
Winter, Kate |
author_facet |
Winter, Kate |
author_sort |
Winter, Kate |
title |
Englacial stratigraphy, debris entrainment and ice sheet stability of Horseshoe Valley, West Antarctica |
title_short |
Englacial stratigraphy, debris entrainment and ice sheet stability of Horseshoe Valley, West Antarctica |
title_full |
Englacial stratigraphy, debris entrainment and ice sheet stability of Horseshoe Valley, West Antarctica |
title_fullStr |
Englacial stratigraphy, debris entrainment and ice sheet stability of Horseshoe Valley, West Antarctica |
title_full_unstemmed |
Englacial stratigraphy, debris entrainment and ice sheet stability of Horseshoe Valley, West Antarctica |
title_sort |
englacial stratigraphy, debris entrainment and ice sheet stability of horseshoe valley, west antarctica |
publishDate |
2016 |
url |
https://nrl.northumbria.ac.uk/id/eprint/31620/ https://nrl.northumbria.ac.uk/id/eprint/31620/1/winter.kate_phd.pdf |
long_lat |
ENVELOPE(22.891,22.891,70.317,70.317) ENVELOPE(-78.000,-78.000,-76.000,-76.000) ENVELOPE(-82.000,-82.000,-80.083,-80.083) ENVELOPE(-75.000,-75.000,-82.000,-82.000) ENVELOPE(-81.333,-81.333,-80.333,-80.333) |
geographic |
Antarctic Bia Evans Ice Stream Horseshoe Valley Institute Ice Stream Patriot Hills West Antarctic Ice Sheet West Antarctica |
geographic_facet |
Antarctic Bia Evans Ice Stream Horseshoe Valley Institute Ice Stream Patriot Hills West Antarctic Ice Sheet West Antarctica |
genre |
Antarc* Antarctic Antarctica Evans Ice Stream ice core Ice Sheet Institute Ice Stream West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Evans Ice Stream ice core Ice Sheet Institute Ice Stream West Antarctica |
op_relation |
https://nrl.northumbria.ac.uk/id/eprint/31620/1/winter.kate_phd.pdf Winter, Kate (2016) Englacial stratigraphy, debris entrainment and ice sheet stability of Horseshoe Valley, West Antarctica. Doctoral thesis, Northumbria University. |
_version_ |
1766264489412395008 |