Debris entrainment at the ice-bedrock interface in sub-freezing temperature conditions (Terre Adélie, Antarctica)

Abstract The debris-rich ice from the bottom 6 m of the 82 m deep CAROLINE (Coastal Antarctic Record of Last Interglacial Natural Environment) ice core reaching bedrock, and from five 2 m long surface cores at Moraine Prudhomme in Terre Adélie (Antarctica) is described and compared to debris-laden i...

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Bibliographic Details
Published in:Journal of Glaciology
Main Authors: Tison, J. -L, Petit, J. -R., Barnola, J. -M., Mahaney, W. C.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 1993
Subjects:
Earth-Surface Processes
Antarctic
The Antarctic
Terre Adélie
Terre-Adélie
Antarc*
Antarctica
ice core
Ice Sheet
Ice Shelf
Journal of Glaciology
Online Access:http://dx.doi.org/10.1017/s0022143000015963
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000015963
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Summary:Abstract The debris-rich ice from the bottom 6 m of the 82 m deep CAROLINE (Coastal Antarctic Record of Last Interglacial Natural Environment) ice core reaching bedrock, and from five 2 m long surface cores at Moraine Prudhomme in Terre Adélie (Antarctica) is described and compared to debris-laden ice from the core-drilling site DIO. Isotopic, total-gas content, CO 2 concentration and SEM investigations of embedded particles, together with ice textures and fabrics, rule out “pressure-melting” regelation around bed obstacles or “freezing-on” as possible mechanisms for the debris entrainment at the ice-bedrock interface. It is suggested that the debris entrapment by purely mechanical means (e.g. shearing) is an efficient process in forming basal ice layers (BIL) at sub-freezing temperatures. This process might be dominant at the margin of the Antarctic ice sheet where no ice shelf exists and where a ramp terminus or a buttressing coastal relief induces compressive flow.

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