Hydrology of a land-terminating Greenlandic outlet glacier
Hydrology is recognised as an important component of the glacial system in alpine environments. In particular, the subglacial drainage of surface meltwaters is known to exert a strong influence on the motion of glaciers and on their capacity to erode the underlying bedrock. This thesis examines the...
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Other Authors: | , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
The University of Edinburgh
2013
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Subjects: | |
Online Access: | http://hdl.handle.net/1842/8286 |
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ftunivedinburgh:oai:era.ed.ac.uk:1842/8286 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Edinburgh Research Archive (ERA - University of Edinburgh) |
op_collection_id |
ftunivedinburgh |
language |
English |
topic |
glaciology hydrology Greenland |
spellingShingle |
glaciology hydrology Greenland Cowton, Thomas Ralph Hydrology of a land-terminating Greenlandic outlet glacier |
topic_facet |
glaciology hydrology Greenland |
description |
Hydrology is recognised as an important component of the glacial system in alpine environments. In particular, the subglacial drainage of surface meltwaters is known to exert a strong influence on the motion of glaciers and on their capacity to erode the underlying bedrock. This thesis examines the more poorly understood drainage system of the Greenland Ice Sheet, with specific focus on Leverett Glacier, a landterminating outlet glacier on the ice sheet’s western margin. Because of the vast size of the ice sheet, the influence of the drainage system could have wide ranging implications, most notably for sea level rise and continental scale landscape evolution. The thesis commences with an investigation into the morphology of the drainage system of the lower 14 km of Leverett Glacier. This is undertaken using a variety of field methods, including dye tracing and the monitoring of proglacial discharge, englacial water levels, surface melt rates and glacier motion. The data reveal that the drainage system of the glacier closely resembles that of alpine glaciers, undergoing an evolution from distributed to channelised drainage morphologies as the melt season progresses. Another aspect of the field data, the suspended sediment load evacuated from the subglacial system in the emerging proglacial river, is then examined to investigate the impact that this drainage system morphology has on the interaction between the glacier and the underlying bedrock or substrate. This demonstrates that the presence of large, efficient subglacial drainage channels allows for the removal of vast quantities of basal debris during much of the melt season, facilitating an erosion rate 1-2 orders of magnitude greater than previously proposed for ice sheet settings. The thesis then focuses on the relationship between discharge, water pressure and ice motion. Observations from Greenlandic and alpine glaciers demonstrate that glaciers generally decelerate through the melt season following a maximum velocity induced by the onset of melt in the ... |
author2 |
Nienow, Peter Sole, Andrew Natural Environment Research Council (NERC) Carnegie Trust for the Universities of Scotland |
format |
Doctoral or Postdoctoral Thesis |
author |
Cowton, Thomas Ralph |
author_facet |
Cowton, Thomas Ralph |
author_sort |
Cowton, Thomas Ralph |
title |
Hydrology of a land-terminating Greenlandic outlet glacier |
title_short |
Hydrology of a land-terminating Greenlandic outlet glacier |
title_full |
Hydrology of a land-terminating Greenlandic outlet glacier |
title_fullStr |
Hydrology of a land-terminating Greenlandic outlet glacier |
title_full_unstemmed |
Hydrology of a land-terminating Greenlandic outlet glacier |
title_sort |
hydrology of a land-terminating greenlandic outlet glacier |
publisher |
The University of Edinburgh |
publishDate |
2013 |
url |
http://hdl.handle.net/1842/8286 |
long_lat |
ENVELOPE(-147.583,-147.583,-85.633,-85.633) |
geographic |
Greenland Leverett Glacier |
geographic_facet |
Greenland Leverett Glacier |
genre |
glacier Greenland greenlandic Ice Sheet Leverett Glacier |
genre_facet |
glacier Greenland greenlandic Ice Sheet Leverett Glacier |
op_relation |
Bartholomew, I., Nienow, P., Sole, A., Mair, D., Cowton, T., Palmer, S. and Wadham, J., 2011a. Supraglacial forcing of subglacial drainage in the ablation zone of the Greenland ice sheet. Geophysical Research Letters, 38(8): L08502. Bartholomew, I., Nienow, P., Sole, A., Mair, D., Cowton, T. and King, M., 2011b. Seasonal variation in Greenland Ice Sheet motion: inland extent and behaviour at higher elevations. Earth and Planetary Science Letters, 307: 271-278. Bartholomew, I., Nienow, P., Sole, A., Mair, D., Cowton, T. and King, M., 2012. Short-term variability in Greenland Ice Sheet motion forced by time-varying meltwater drainage: Implications for the relationship between subglacial drainage system behavior and ice velocity. Journal of Geophysical Research - Earth Surface, 117(F3): F03002. Cowton, T., Nienow, P., Bartholomew, I., Sole, A. and Mair, D., 2012. Rapid erosion beneath the Greenland ice sheet. Geology, 40(4): 343-346. Cowton, T., Nienow, P., Sole, A., Wadham, J., Lis, G., Bartholomew, I., Mair, D. and Chandler, D.M., 2013. Evolution of drainage system morphology at a landterminating Greenlandic outlet glacier. Journal of Geophysical Research - Earth Surface. Sole, A., Nienow, P., Bartholomew, I., Mair, D., Cowton, T., King, M. and Burke, M., 2010. C42A-02 Seasonal acceleration of the Greenland Ice Sheet in contrasting melt-seasons, 2010 Fall Meeting , AGU, San Francisco, Abstracts, pp. 391. http://hdl.handle.net/1842/8286 |
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1772814642869960704 |
spelling |
ftunivedinburgh:oai:era.ed.ac.uk:1842/8286 2023-07-30T04:03:37+02:00 Hydrology of a land-terminating Greenlandic outlet glacier Cowton, Thomas Ralph Nienow, Peter Sole, Andrew Natural Environment Research Council (NERC) Carnegie Trust for the Universities of Scotland 2013-11-28 application/msword application/pdf http://hdl.handle.net/1842/8286 en eng The University of Edinburgh Bartholomew, I., Nienow, P., Sole, A., Mair, D., Cowton, T., Palmer, S. and Wadham, J., 2011a. Supraglacial forcing of subglacial drainage in the ablation zone of the Greenland ice sheet. Geophysical Research Letters, 38(8): L08502. Bartholomew, I., Nienow, P., Sole, A., Mair, D., Cowton, T. and King, M., 2011b. Seasonal variation in Greenland Ice Sheet motion: inland extent and behaviour at higher elevations. Earth and Planetary Science Letters, 307: 271-278. Bartholomew, I., Nienow, P., Sole, A., Mair, D., Cowton, T. and King, M., 2012. Short-term variability in Greenland Ice Sheet motion forced by time-varying meltwater drainage: Implications for the relationship between subglacial drainage system behavior and ice velocity. Journal of Geophysical Research - Earth Surface, 117(F3): F03002. Cowton, T., Nienow, P., Bartholomew, I., Sole, A. and Mair, D., 2012. Rapid erosion beneath the Greenland ice sheet. Geology, 40(4): 343-346. Cowton, T., Nienow, P., Sole, A., Wadham, J., Lis, G., Bartholomew, I., Mair, D. and Chandler, D.M., 2013. Evolution of drainage system morphology at a landterminating Greenlandic outlet glacier. Journal of Geophysical Research - Earth Surface. Sole, A., Nienow, P., Bartholomew, I., Mair, D., Cowton, T., King, M. and Burke, M., 2010. C42A-02 Seasonal acceleration of the Greenland Ice Sheet in contrasting melt-seasons, 2010 Fall Meeting , AGU, San Francisco, Abstracts, pp. 391. http://hdl.handle.net/1842/8286 glaciology hydrology Greenland Thesis or Dissertation Doctoral PhD Doctor of Philosophy 2013 ftunivedinburgh 2023-07-09T20:33:45Z Hydrology is recognised as an important component of the glacial system in alpine environments. In particular, the subglacial drainage of surface meltwaters is known to exert a strong influence on the motion of glaciers and on their capacity to erode the underlying bedrock. This thesis examines the more poorly understood drainage system of the Greenland Ice Sheet, with specific focus on Leverett Glacier, a landterminating outlet glacier on the ice sheet’s western margin. Because of the vast size of the ice sheet, the influence of the drainage system could have wide ranging implications, most notably for sea level rise and continental scale landscape evolution. The thesis commences with an investigation into the morphology of the drainage system of the lower 14 km of Leverett Glacier. This is undertaken using a variety of field methods, including dye tracing and the monitoring of proglacial discharge, englacial water levels, surface melt rates and glacier motion. The data reveal that the drainage system of the glacier closely resembles that of alpine glaciers, undergoing an evolution from distributed to channelised drainage morphologies as the melt season progresses. Another aspect of the field data, the suspended sediment load evacuated from the subglacial system in the emerging proglacial river, is then examined to investigate the impact that this drainage system morphology has on the interaction between the glacier and the underlying bedrock or substrate. This demonstrates that the presence of large, efficient subglacial drainage channels allows for the removal of vast quantities of basal debris during much of the melt season, facilitating an erosion rate 1-2 orders of magnitude greater than previously proposed for ice sheet settings. The thesis then focuses on the relationship between discharge, water pressure and ice motion. Observations from Greenlandic and alpine glaciers demonstrate that glaciers generally decelerate through the melt season following a maximum velocity induced by the onset of melt in the ... Doctoral or Postdoctoral Thesis glacier Greenland greenlandic Ice Sheet Leverett Glacier Edinburgh Research Archive (ERA - University of Edinburgh) Greenland Leverett Glacier ENVELOPE(-147.583,-147.583,-85.633,-85.633) |