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Subglacial processes on an Antarctic ice stream bed. 1 : Sediment transport and bedform genesis inferred from marine geophysical data.

Livingstone, S.J. and Stokes, C.R. and Ó Cofaigh, C. and Hillenbrand, C-D. and Vieli, A. and Jamieson, S.S.R. and Spagnolo, M. and Dowdeswell, J. (2016) 'Subglacial processes on an Antarctic ice stream bed. 1 : Sediment transport and bedform genesis inferred from marine geophysical data.', Journal of glaciology., 62 (232). pp. 270-284.

Abstract

The spatial pattern and morphometry of bedforms and their relationship to sediment thickness have been analysed in the Marguerite Bay Palaeo-ice stream Trough, western Antarctic Peninsula. Over 17 000 glacial landforms were measured from geophysical datasets, and sediment thickness maps were generated from acoustic sub-bottom profiler data. These analyses reveal a complex bedform pattern characterised by considerable spatial diversity, influenced heavily by the underlying substrate. The variability in length and density of mega-scale lineations indicates an evolving bedform signature, whereby landforms are preserved at different stages of maturity. Lineation generation and attenuation is associated with regions of thick, soft till where deformation was likely to be the greatest. The distribution of soft till and the localised extent of grounding-zone wedges (GZWs) indicate a dynamic sedimentary system characterised by considerable spatio-temporal variability in sediment erosion, transport and deposition. Formation of GZWs on the outer shelf of Marguerite Trough, within the error range of the radiocarbon dates, requires large sediment fluxes (upwards of 1000 m3 a−1 (m grounding line width)−1), and a >1 m thick mobile till layer, or rapid basal sliding velocities (upwards of 6 km a−1).

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Status:Peer-reviewed
Publisher Web site:http://dx.doi.org/10.1017/jog.2016.18
Publisher statement:Copyright © The Author(s) 2016 This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Date accepted:05 November 2015
Date deposited:01 February 2016
Date of first online publication:17 March 2016
Date first made open access:No date available

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