Radar‐Sounding Characterization of the Subglacial Groundwater Table Beneath Hiawatha Glacier, Greenland

Bessette, JT; Schroeder, DM; Jordan, TM; MacGregor, JA. 2021 Radar‐Sounding Characterization of the Subglacial Groundwater Table Beneath Hiawatha Glacier, Greenland. Geophysical Research Letters, 48 (10). 1-11. https://doi.org/10.1029/2020GL091432

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Official URL: http://dx.doi.org/10.1029/2020GL091432

Abstract/Summary

Radar-sounding surveys associated with the discovery of a large impact crater beneath Hiawatha Glacier, Greenland, revealed bright, flat subglacial reflections hypothesized to originate from a subglacial groundwater table. We test this hypothesis using radiometric and hydrologic analysis of those radar data. The dielectric loss between the reflection from the top of the basal layer and subglacial reflection and their reflectivity difference represent dual constraints upon the complex permittivity of the basal material. Either ice-cemented debris or fractured, well-drained bedrock explain the basal layer's radiometric properties. The subglacial reflector's geometry is parallel to isopotential hydraulic head contours, located 7.5–15.3 m below the interface, and 11 ± 7 dB brighter than the ice–basal layer reflection. We conclude that this subglacial reflection is a groundwater table and that its detection was enabled by the wide bandwidth of the radar system and unusual geologic setting, suggesting a path for future direct radar detection of subglacial groundwater elsewhere.

Item Type: Publication - Article
Additional Information. Not used in RCUK Gateway to Research.: Correspondence to:J. T. Bessette,jbessett@buffalo.edu
Additional Keywords: Radiometric and hydrologic analysis of radar-sounding data is consistent with a reflection from a subglacial groundwater table• Dual radiometric constraints indicate a layer of either debris-laden ice or fractured bedrock above the subglacial groundwater table• This first detection of a subglacial groundwater table was enabled by favorable local geology, thin ice and the wide bandwidth radar system
Divisions: Plymouth Marine Laboratory > Science Areas > Earth Observation Science and Applications
Depositing User: S Hawkins
Date made live: 26 May 2021 11:09
Last Modified: 26 May 2021 11:09
URI: http://plymsea.ac.uk/id/eprint/9226

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