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Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), Greenland.
- Source :
-
Journal of Glaciology . Aug2022, Vol. 68 Issue 270, p665-684. 20p. - Publication Year :
- 2022
-
Abstract
- 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 ā¤ 10ā6 m sā1. 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. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00221430
- Volume :
- 68
- Issue :
- 270
- Database :
- Academic Search Index
- Journal :
- Journal of Glaciology
- Publication Type :
- Academic Journal
- Accession number :
- 158140257
- Full Text :
- https://doi.org/10.1017/jog.2021.121