Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), Greenland
Subglacial hydrology modulates basal motion but remains poorly constrained, particularly for soft-bedded Greenlandic outlet glaciers. Here, we report detailed measurements of the response of subglacial water pressure to the connection and drainage of adjacent water-filled boreholes drilled through k...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2022-08-01
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| Series: | Journal of Glaciology |
| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143021001210/type/journal_article |
| _version_ | 1811155756910641152 |
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| author | Samuel H. Doyle Bryn Hubbard Poul Christoffersen Robert Law Duncan R. Hewitt Jerome A. Neufeld Charlotte M. Schoonman Thomas R. Chudley Marion Bougamont |
| author_facet | Samuel H. Doyle Bryn Hubbard Poul Christoffersen Robert Law Duncan R. Hewitt Jerome A. Neufeld Charlotte M. Schoonman Thomas R. Chudley Marion Bougamont |
| author_sort | Samuel H. Doyle |
| collection | DOAJ |
| description | Subglacial hydrology modulates basal motion but remains poorly constrained, particularly for soft-bedded Greenlandic outlet glaciers. Here, we report detailed measurements of the response of subglacial water pressure to the connection and drainage of adjacent water-filled boreholes drilled through kilometre-thick ice on Sermeq Kujalleq (Store Glacier). These measurements provide evidence for gap opening at the ice-sediment interface, Darcian flow through the sediment layer, and the forcing of water pressure in hydraulically-isolated cavities by stress transfer. We observed a small pressure drop followed by a large pressure rise in response to the connection of an adjacent borehole, consistent with the propagation of a flexural wave within the ice and underlying deformable sediment. We interpret the delayed pressure rise as evidence of no pre-existing conduit and the progressive decrease in hydraulic transmissivity as the closure of a narrow (< 1.5 mm) gap opened at the ice-sediment interface, and a reversion to Darcian flow through the sediment layer with a hydraulic conductivity of ≤ 10−6 m s−1. We suggest that gap opening at the ice-sediment interface deserves further attention as it will occur naturally in response to the rapid pressurisation of water at the bed. |
| first_indexed | 2024-04-10T04:39:56Z |
| format | Article |
| id | doaj.art-b42d1c1436d1446fa38ba96388fa36a5 |
| institution | Directory Open Access Journal |
| issn | 0022-1430 1727-5652 |
| language | English |
| last_indexed | 2024-04-10T04:39:56Z |
| publishDate | 2022-08-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj.art-b42d1c1436d1446fa38ba96388fa36a52023-03-09T12:41:17ZengCambridge University PressJournal of Glaciology0022-14301727-56522022-08-016866568410.1017/jog.2021.121Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), GreenlandSamuel H. Doyle0https://orcid.org/0000-0002-0853-431XBryn Hubbard1https://orcid.org/0000-0002-3565-3875Poul Christoffersen2https://orcid.org/0000-0003-2643-8724Robert Law3Duncan R. Hewitt4Jerome A. Neufeld5Charlotte M. Schoonman6Thomas R. Chudley7https://orcid.org/0000-0001-8547-1132Marion Bougamont8Centre for Glaciology, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, SY23 3DB, UKCentre for Glaciology, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, SY23 3DB, UKScott Polar Research Institute, Cambridge University, Cambridge, CB2 1ER, UKScott Polar Research Institute, Cambridge University, Cambridge, CB2 1ER, UKDepartment of Mathematics, University College London, 25 Gordon Street, London, WC1H 0AYInstitute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK BP Institute, University of Cambridge, Madingley Rise, Cambridge CB3 0EZ, UK Department of Earth Sciences, Bullard Laboratories, University of Cambridge, Madingley Rise, Cambridge CB3 0EZ, UKScott Polar Research Institute, Cambridge University, Cambridge, CB2 1ER, UKScott Polar Research Institute, Cambridge University, Cambridge, CB2 1ER, UKScott Polar Research Institute, Cambridge University, Cambridge, CB2 1ER, UKSubglacial hydrology modulates basal motion but remains poorly constrained, particularly for soft-bedded Greenlandic outlet glaciers. Here, we report detailed measurements of the response of subglacial water pressure to the connection and drainage of adjacent water-filled boreholes drilled through kilometre-thick ice on Sermeq Kujalleq (Store Glacier). These measurements provide evidence for gap opening at the ice-sediment interface, Darcian flow through the sediment layer, and the forcing of water pressure in hydraulically-isolated cavities by stress transfer. We observed a small pressure drop followed by a large pressure rise in response to the connection of an adjacent borehole, consistent with the propagation of a flexural wave within the ice and underlying deformable sediment. We interpret the delayed pressure rise as evidence of no pre-existing conduit and the progressive decrease in hydraulic transmissivity as the closure of a narrow (< 1.5 mm) gap opened at the ice-sediment interface, and a reversion to Darcian flow through the sediment layer with a hydraulic conductivity of ≤ 10−6 m s−1. We suggest that gap opening at the ice-sediment interface deserves further attention as it will occur naturally in response to the rapid pressurisation of water at the bed.https://www.cambridge.org/core/product/identifier/S0022143021001210/type/journal_article |
| spellingShingle | Samuel H. Doyle Bryn Hubbard Poul Christoffersen Robert Law Duncan R. Hewitt Jerome A. Neufeld Charlotte M. Schoonman Thomas R. Chudley Marion Bougamont Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), Greenland Journal of Glaciology |
| title | Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), Greenland |
| title_full | Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), Greenland |
| title_fullStr | Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), Greenland |
| title_full_unstemmed | Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), Greenland |
| title_short | Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), Greenland |
| title_sort | water flow through sediments and at the ice sediment interface beneath sermeq kujalleq store glacier greenland |
| url | https://www.cambridge.org/core/product/identifier/S0022143021001210/type/journal_article |
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