Physical conditions of fast glacier flow: 1. measurements from boreholes drilled to the bed of Store Glacier, West Greenland ...

• Main Authors: Doyle, SH, Hubbard, B, Christoffersen, Poul, Young, TJ, Hofstede, C, Bougamont, MH, Box, JE, Hubbard, A
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell 2018
• Subjects: Greenland; ice sheet; hydrology; dynamics; borehole; sediment; glacier; Ice Sheet
• Online Access: https://dx.doi.org/10.17863/cam.17485; https://www.repository.cam.ac.uk/handle/1810/270570

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 600m 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. ...