Testing models of ice cap extents, South Georgia, sub-Antarctic

Barlow, N.L.M., Bentley, M.J., Spada, G., Evans, D.J.A., Hansom, J.D. , Brader, M.D., White, D.A., Zander, A. and Berg, S. (2016) Testing models of ice cap extents, South Georgia, sub-Antarctic. Quaternary Science Reviews, 154, pp. 157-168. (doi:10.1016/j.quascirev.2016.11.007)

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Abstract

The extent of Last Glacial Maximum ice in South Georgia is contested, with two alternative hypotheses: an extensive (maximum) model ofice reaching the edge of the continental shelf, or a restricted(minimum) model with ice constrained within the inner fjords. We present new relative sea-level dataset for South Georgia, summarising published and new geomorphological evidence for the marine limit and elevations offormer sea levels on the island. Using a glacial isostatic adjustmentmodel (ALMA) specifically suited to regional modelling and working at high spatial resolutions, combined with a series of simulated ice-load histories, we use the relative sea-level data to test between the restricted and extensive ice extent scenarios. The model results suggest that there was most likely an extensive Last Glacial Maximum glaciation of South Georgia, implying that the island was covered by thick (>1000 m) ice, probably to the edge of the continental shelf, with deglaciation occurring relatively early (ca. 15 ka BP, though independent data suggest this may have been as early as 18 ka). The presence of an extensive ice cap extending to the shelf edge would imply that if there were any biologic refugia around South Georgia, they must have been relatively localised and restricted to the outermost shelf.

Item Type:Articles
Additional Information:G.S. is funded by Programma Nazionale di Ricerche in Antartide (PNRA) 2013/B2.06 (CUP D32I14000230005).
Keywords:Last glacial maximum, glacial isostatic adjustment, sea-level change, South Georgia, sub-Antarctic, coastal geomorphology.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hansom, Dr Jim
Authors: Barlow, N.L.M., Bentley, M.J., Spada, G., Evans, D.J.A., Hansom, J.D., Brader, M.D., White, D.A., Zander, A., and Berg, S.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences > Geography
Journal Name:Quaternary Science Reviews
Journal Abbr.:QSR
Publisher:Elsevier
ISSN:0277-3791
ISSN (Online):1873-457X
Published Online:18 November 2016
Copyright Holders:Copyright © 2016 Elsevier Ltd.
First Published:First published in Quaternary Science Reviews 154: 157-168
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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