Basal crevasses in Larsen C Ice Shelf and implications for their global abundance

Luckman, A.; Jansen, D.; Kulessa, B.; King, Edward ORCID: https://orcid.org/0000-0003-3793-3915; Sammonds, P.; Benn, D.I.. 2012 Basal crevasses in Larsen C Ice Shelf and implications for their global abundance. The Cryosphere, 6 (1). 113-123. 10.5194/tc-6-113-2012

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Abstract/Summary

Basal crevasses extend upwards from the base of ice bodies and can penetrate more than halfway through the ice column under conditions found commonly on ice shelves. As a result, they may locally modify the exchange of mass and energy between ice shelf and ocean, and by altering the shelf's mechanical properties could play a fundamental role in ice shelf stability. Although early studies revealed that such features may be abundant on Antarctic ice shelves, their geometrical properties and spatial distribution has gained little attention. We investigate basal crevasses in Larsen C Ice Shelf using field radar survey, remote sensing and numerical modelling. We demonstrate that a group of features visible in MODIS imagery are the surface expressions of basal crevasses in the form of surface troughs, and find that basal crevasses can be generated as a result of stresses well downstream of the grounding line. We show that linear elastic fracture mechanics modelling is a good predictor of basal crevasse penetration height where stresses are predominantly tensile, and that measured surface trough depth does not always reflect this height, probably because of snow accumulation in the trough, marine ice accretion in the crevasse, or stress bridging from the surrounding ice. We conclude that all features visible in MODIS imagery of ice shelves and previously labelled simply as "crevasses", where they are not full thickness rifts, must be basal crevasse troughs, highlighting a fundamental structural property of many ice shelves that may have been previously overlooked.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.5194/tc-6-113-2012
Programmes:	BAS Programmes > Polar Science for Planet Earth (2009 - ) > Ice Sheets
ISSN:	1994-0416
Additional Information. Not used in RCUK Gateway to Research.:	Open access article made available under a CC-BY Creative Commons Attribution license.
Date made live:	19 Mar 2012 13:46 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/17363

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