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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.; Stokes, C.R.; O Cofaigh, C.; Hillenbrand, C-D.; Vieli, A.; Jamieson, S.S.R.; Spagnolo, M.; Dowdeswell, J.

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


Authors

S.J. Livingstone

C-D. Hillenbrand

A. Vieli

M. Spagnolo

J. Dowdeswell



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).

Citation

Livingstone, S., Stokes, C., O Cofaigh, C., Hillenbrand, C., Vieli, A., Jamieson, S., …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), 270-284. https://doi.org/10.1017/jog.2016.18

Journal Article Type Article
Acceptance Date Nov 5, 2015
Online Publication Date Mar 17, 2016
Publication Date Apr 1, 2016
Deposit Date Jan 27, 2016
Publicly Available Date Feb 1, 2016
Journal Journal of Glaciology
Print ISSN 0022-1430
Electronic ISSN 1727-5652
Publisher International Glaciological Society
Peer Reviewed Peer Reviewed
Volume 62
Issue 232
Pages 270-284
DOI https://doi.org/10.1017/jog.2016.18

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Copyright 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.







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