Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland
Marine‐terminating outlet glaciers of the Greenland Ice Sheet make significant contributions to global sea level rise, yet the conditions that facilitate their fast flow remain poorly constrained owing to a paucity of data. We drilled and instrumented seven boreholes on Store Glacier, Greenland, to...
Published in: | Journal of Geophysical Research: Earth Surface |
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American Geophysical Union
2018
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Online Access: | http://nora.nerc.ac.uk/id/eprint/519729/ https://nora.nerc.ac.uk/id/eprint/519729/1/Doyle_et_al-2018-Journal_of_Geophysical_Research__Earth_Surface.pdf https://doi.org/10.1002/2017JF004529 |
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ftnerc:oai:nora.nerc.ac.uk:519729 2023-05-15T13:49:34+02:00 Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland Doyle, S.H. Hubbard, B. Christoffersen, P. Young, T.J. Hofstede, C. Bougamont, M. Box, J.E. Hubbard, A. 2018-02 text http://nora.nerc.ac.uk/id/eprint/519729/ https://nora.nerc.ac.uk/id/eprint/519729/1/Doyle_et_al-2018-Journal_of_Geophysical_Research__Earth_Surface.pdf https://doi.org/10.1002/2017JF004529 en eng American Geophysical Union https://nora.nerc.ac.uk/id/eprint/519729/1/Doyle_et_al-2018-Journal_of_Geophysical_Research__Earth_Surface.pdf Doyle, S.H.; Hubbard, B.; Christoffersen, P.; Young, T.J.; Hofstede, C.; Bougamont, M.; Box, J.E.; Hubbard, A. 2018 Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland. Journal of Geophysical Research: Earth Surface, 123 (2). 324-348. https://doi.org/10.1002/2017JF004529 <https://doi.org/10.1002/2017JF004529> cc_by_4 CC-BY Publication - Article PeerReviewed 2018 ftnerc https://doi.org/10.1002/2017JF004529 2023-02-04T19:46:21Z Marine‐terminating outlet glaciers of the Greenland Ice Sheet make significant contributions to global sea level rise, yet the conditions that facilitate their fast flow remain poorly constrained owing to a paucity of data. We drilled and instrumented seven boreholes on Store Glacier, Greenland, to monitor subglacial water pressure, temperature, electrical conductivity, and turbidity along with englacial ice temperature and deformation. These observations were supplemented by surface velocity and meteorological measurements to gain insight into the conditions and mechanisms of fast glacier flow. Located 30 km from the calving front, each borehole drained rapidly on attaining ∼600 m depth indicating a direct connection with an active subglacial hydrological system. Persistently high subglacial water pressures indicate low effective pressure (180–280 kPa), with small‐amplitude variations correlated with notable peaks in surface velocity driven by the diurnal melt cycle and longer periods of melt and rainfall. The englacial deformation profile determined from borehole tilt measurements indicates that 63–71% of total ice motion occurred at the bed, with the remaining 29–37% predominantly attributed to enhanced deformation in the lowermost 50–100 m of the ice column. We interpret this lowermost 100 m to be formed of warmer, pre‐Holocene ice overlying a thin (0–8 m) layer of temperate basal ice. Our observations are consistent with a spatially extensive and persistently inefficient subglacial drainage system that we hypothesize comprises drainage both at the ice‐sediment interface and through subglacial sediments. This configuration has similarities to that interpreted beneath dynamically analogous Antarctic ice streams, Alaskan tidewater glaciers, and glaciers in surge. Article in Journal/Newspaper Antarc* Antarctic glacier Greenland Ice Sheet Tidewater Natural Environment Research Council: NERC Open Research Archive Antarctic Greenland Journal of Geophysical Research: Earth Surface 123 2 324 348 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Marine‐terminating outlet glaciers of the Greenland Ice Sheet make significant contributions to global sea level rise, yet the conditions that facilitate their fast flow remain poorly constrained owing to a paucity of data. We drilled and instrumented seven boreholes on Store Glacier, Greenland, to monitor subglacial water pressure, temperature, electrical conductivity, and turbidity along with englacial ice temperature and deformation. These observations were supplemented by surface velocity and meteorological measurements to gain insight into the conditions and mechanisms of fast glacier flow. Located 30 km from the calving front, each borehole drained rapidly on attaining ∼600 m depth indicating a direct connection with an active subglacial hydrological system. Persistently high subglacial water pressures indicate low effective pressure (180–280 kPa), with small‐amplitude variations correlated with notable peaks in surface velocity driven by the diurnal melt cycle and longer periods of melt and rainfall. The englacial deformation profile determined from borehole tilt measurements indicates that 63–71% of total ice motion occurred at the bed, with the remaining 29–37% predominantly attributed to enhanced deformation in the lowermost 50–100 m of the ice column. We interpret this lowermost 100 m to be formed of warmer, pre‐Holocene ice overlying a thin (0–8 m) layer of temperate basal ice. Our observations are consistent with a spatially extensive and persistently inefficient subglacial drainage system that we hypothesize comprises drainage both at the ice‐sediment interface and through subglacial sediments. This configuration has similarities to that interpreted beneath dynamically analogous Antarctic ice streams, Alaskan tidewater glaciers, and glaciers in surge. |
format |
Article in Journal/Newspaper |
author |
Doyle, S.H. Hubbard, B. Christoffersen, P. Young, T.J. Hofstede, C. Bougamont, M. Box, J.E. Hubbard, A. |
spellingShingle |
Doyle, S.H. Hubbard, B. Christoffersen, P. Young, T.J. Hofstede, C. Bougamont, M. Box, J.E. Hubbard, A. Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland |
author_facet |
Doyle, S.H. Hubbard, B. Christoffersen, P. Young, T.J. Hofstede, C. Bougamont, M. Box, J.E. Hubbard, A. |
author_sort |
Doyle, S.H. |
title |
Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland |
title_short |
Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland |
title_full |
Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland |
title_fullStr |
Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland |
title_full_unstemmed |
Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland |
title_sort |
physical conditions of fast glacier flow: 1. measurements from boreholes drilled to the bed of store glacier, west greenland |
publisher |
American Geophysical Union |
publishDate |
2018 |
url |
http://nora.nerc.ac.uk/id/eprint/519729/ https://nora.nerc.ac.uk/id/eprint/519729/1/Doyle_et_al-2018-Journal_of_Geophysical_Research__Earth_Surface.pdf https://doi.org/10.1002/2017JF004529 |
geographic |
Antarctic Greenland |
geographic_facet |
Antarctic Greenland |
genre |
Antarc* Antarctic glacier Greenland Ice Sheet Tidewater |
genre_facet |
Antarc* Antarctic glacier Greenland Ice Sheet Tidewater |
op_relation |
https://nora.nerc.ac.uk/id/eprint/519729/1/Doyle_et_al-2018-Journal_of_Geophysical_Research__Earth_Surface.pdf Doyle, S.H.; Hubbard, B.; Christoffersen, P.; Young, T.J.; Hofstede, C.; Bougamont, M.; Box, J.E.; Hubbard, A. 2018 Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland. Journal of Geophysical Research: Earth Surface, 123 (2). 324-348. https://doi.org/10.1002/2017JF004529 <https://doi.org/10.1002/2017JF004529> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1002/2017JF004529 |
container_title |
Journal of Geophysical Research: Earth Surface |
container_volume |
123 |
container_issue |
2 |
container_start_page |
324 |
op_container_end_page |
348 |
_version_ |
1766251756640010240 |