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Position and variability of complex structures in the central East Antarctic Ice Sheet

Wrona, Thilo; Wolovick, Michael J.; Ferraccioli, Fausto; Corr, Hugh; Jordan, Tom; Siegert, Martin J.. 2017 Position and variability of complex structures in the central East Antarctic Ice Sheet. In: Siegert, M.J.; Jamieson, S.S.R.; White, D.A., (eds.) Exploration of subsurface Antarctica: uncovering past changes and modern processes. London, Geological Society of London. (Geological Society of London, Special Publication, 461).

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Abstract/Summary

Although the flow of the East Antarctic Ice Sheet is well constrained from surface measurements and altimetry, our knowledge of the dynamic processes within the ice sheet remains limited. Recent high-resolution radar data from the Gamburtsev Subglacial Mountains in central East Antarctica reveal a series of anomalous englacial reflectors in the lower half of the ice column that cannot be explained by conventional ice flow. Expanding on previous analyses, we describe the geometrical and morphological features of 12 of these anomalous reflectors. Our description reveals a previously unacknowledged diversity in size, geometry and internal structure of these reflectors. We are able to identify four distinct morphological features: (1) fingers; (2) inclusions; (3) sheets; and (4) folds. The ‘fingers’ and ‘inclusions’ probably form by shear instabilities at the boundary between the reflectors and the surrounding meteoric ice. The ‘sheets’ highlight that basal ice can be uplifted off of the bed and above surrounding meteoric ice, and the ‘folds’ may have formed in local regions of converging flow associated with subglacial topography. The study provides key insights into the rheology, stress and deformational regimes deep within the central East Antarctic Ice Sheet.

Item Type: Publication - Book Section
Digital Object Identifier (DOI): 10.1144/SP461.12
Programmes: BAS Programmes > BAS Programmes 2015 > Geology and Geophysics
ISSN: 0016-7649
Date made live: 27 Jun 2017 08:45 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/515988

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