Early glacial maximum and deglaciation at sub-Antarctic Marion Island from cosmogenic ³⁶Cl exposure dating

Rudolph, E. M., Hedding, D. W., Fabel, D. , Hodgson, D. A., Gheorghiu, D. M. , Shanks, R. and Nel, W. (2020) Early glacial maximum and deglaciation at sub-Antarctic Marion Island from cosmogenic ³⁶Cl exposure dating. Quaternary Science Reviews, 231, 106208. (doi: 10.1016/j.quascirev.2020.106208)

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Southern Hemisphere glacial chronologies can provide valuable insights into interactions between glaciation and past climate changes, but are not well constrained on most sub-Antarctic islands. We present the first cosmogenic ³⁶Cl exposure ages of deglaciated bedrock surfaces and moraine deposits from sub-Antarctic Marion Island in the southern Indian Ocean. Results show that the ice reached a local Last Glacial Maximum before 34 ka and retreated, with no re-advances, but possibly minor stand stills, until ∼17 ka. This early deglaciation left island surfaces below 850 m a.s.l. ice-free after ∼19 ka, and any subsequent advances during the Antarctic Cold Reversal or Holocene cooling periods would have been restricted to the interior. This glacial chronology is similar to that of some other sub-Antarctic Islands (e.g. the Kerguelen archipelago, Auckland and Campbell islands, and possibly South Georgia) and a number of other Southern Hemisphere glaciers (e.g. in Patagonia and New Zealand) and adds to evidence that suggest the Southern Hemisphere was in a glacial maxima earlier than the global LGM. We suggest a combination of declining temperatures, a northward migration of oceanic fronts and the Southern Hemisphere westerly winds (causing precipitation changes), as well as the physiography of Marion Island, created optimal conditions for glacier growth during Marine Isotope Stage (MIS) 3 instead of MIS 2. Our findings redefine the glacial history of Marion Island, and have implications for future investigations on post-glacial landscape development and ecological succession.

Item Type:Articles
Additional Information:The South African National Antarctic Programme and the Department of Environmental Affairs for logistical support, and the National Research Foundation for financial support (SANAP-NRF: 110723).
Glasgow Author(s) Enlighten ID:Shanks, Dr Richard and Fabel, Dr Derek and Gheorghiu, Dr Delia M
Creator Roles:
Fabel, D.Methodology, Formal analysis, Resources, Writing – review and editing, Visualization
Gheorghiu, D. M.Methodology, Formal analysis, Resources, Data curation, Writing – review and editing
Shanks, R.Methodology, Formal analysis, Resources
Authors: Rudolph, E. M., Hedding, D. W., Fabel, D., Hodgson, D. A., Gheorghiu, D. M., Shanks, R., and Nel, W.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Quaternary Science Reviews
ISSN (Online):1873-457X
Published Online:12 February 2020
Copyright Holders:Copyright © 2020 Elsevier Ltd.
First Published:First published in Quaternary Science Reviews 231: 106208
Publisher Policy:Reproduced in accordance with the publisher copyright policy
Data DOI:10.17632/xx7znfc8xv.1

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