Physical Conditions of Fast Glacier Flow1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland

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Physical Conditions of Fast Glacier Flow : 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland. / Doyle, Samuel; Hubbard, Bryn; Christoffersen, P.; Young, T. J.; Hofstede, C.; Bougamont, M.; Box, J. E.; Hubbard, Alun.

In: Journal of Geophysical Research: Earth Surface, Vol. 123, No. 2, 24.02.2018, p. 324-348.

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Harvard

Doyle, S, Hubbard, B, Christoffersen, P, Young, TJ, Hofstede, C, Bougamont, M, Box, JE & 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, vol. 123, no. 2, pp. 324-348. https://doi.org/10.1002/2017JF004529

APA

Doyle, S., 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

Vancouver

Doyle S, Hubbard B, Christoffersen P, Young TJ, Hofstede C, Bougamont M et al. 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. 2018 Feb 24;123(2):324-348. https://doi.org/10.1002/2017JF004529

Author

Doyle, Samuel ; Hubbard, Bryn ; Christoffersen, P. ; Young, T. J. ; Hofstede, C. ; Bougamont, M. ; Box, J. E. ; Hubbard, Alun. / Physical Conditions of Fast Glacier Flow : 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland. In: Journal of Geophysical Research: Earth Surface. 2018 ; Vol. 123, No. 2. pp. 324-348.

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@article{73f97b45872648a883d1c6f337282829,
title = "Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland",
abstract = "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 30km 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. 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 100m 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",
keywords = "Greenland, ice sheet, hydrology, dynamics, borehole, sediment",
author = "Samuel Doyle and Bryn Hubbard and P. Christoffersen and Young, {T. J.} and C. Hofstede and M. Bougamont and Box, {J. E.} and Alun Hubbard",
year = "2018",
month = feb,
day = "24",
doi = "10.1002/2017JF004529",
language = "English",
volume = "123",
pages = "324--348",
journal = "Journal of Geophysical Research: Earth Surface",
issn = "2169-9003",
publisher = "Wiley",
number = "2",

}

RIS (suitable for import to EndNote) - Download

TY - JOUR

T1 - Physical Conditions of Fast Glacier Flow

T2 - 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland

AU - Doyle, Samuel

AU - Hubbard, Bryn

AU - Christoffersen, P.

AU - Young, T. J.

AU - Hofstede, C.

AU - Bougamont, M.

AU - Box, J. E.

AU - Hubbard, Alun

PY - 2018/2/24

Y1 - 2018/2/24

N2 - 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 30km 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. 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 100m 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

AB - 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 30km 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. 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 100m 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

KW - Greenland

KW - ice sheet

KW - hydrology

KW - dynamics

KW - borehole

KW - sediment

U2 - 10.1002/2017JF004529

DO - 10.1002/2017JF004529

M3 - Article

VL - 123

SP - 324

EP - 348

JO - Journal of Geophysical Research: Earth Surface

JF - Journal of Geophysical Research: Earth Surface

SN - 2169-9003

IS - 2

ER -

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