Episodic erosion in West Antarctica inferred from cosmogenic 3He and 10Be in olivine from Mount Hampton

Carracedo, A., Rodes, A. , Smellie, J.L. and Stuart, F.M. (2019) Episodic erosion in West Antarctica inferred from cosmogenic 3He and 10Be in olivine from Mount Hampton. Geomorphology, 327, pp. 438-445. (doi:10.1016/j.geomorph.2018.11.019)

Carracedo, A., Rodes, A. , Smellie, J.L. and Stuart, F.M. (2019) Episodic erosion in West Antarctica inferred from cosmogenic 3He and 10Be in olivine from Mount Hampton. Geomorphology, 327, pp. 438-445. (doi:10.1016/j.geomorph.2018.11.019)

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Abstract

The polar climate of Antarctica results in the lowest erosion rates on Earth. The low long-term erosion history of high elevation mountain tops that are exposed above the ice preserve a record of climate change that can be accessed using cosmogenic nuclides. However, unravelling the complexity of the long-term denudation histories of Antarctic summits is frequently hampered by intermittent ice cover. The aim of this work is to identify denudation rate changes in a surface that has been continuously exposed since the middle Miocene. We have measured stable (3He) and radioactive (10Be) cosmogenic nuclides in olivine from lherzolite xenoliths from the summit of the Mount Hampton shield volcano within the West Antarctic Ice Sheet. The peak (3200 m) has never been covered by the current ice sheet and local ice caps, consequently the data record the subaerial erosion history of a mountain top within the Antarctic interior. The 10Be concentrations in the olivines yield minimum exposure ages (33 to 501 ka) that are significantly younger than those derived from the cosmogenic 3He (90 to 1101 ka). The data reveal a complex exposure history that provide an integrated long-term erosion rate of between 0.2 and 0.7 m/My that is most likely caused by mechanical weathering. Inverse modelling shows that the data are readily explained by episodic erosion, consisting of one to five erosion pulses that may record major regional climatic changes.

Item Type:Articles
Additional Information:The PhD of AC was supported by NERC (NE/I528118/1) and SUERC.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Carracedo Plumed, Miss Ana and Stuart, Professor Finlay and Rodes, Dr Angel
Authors: Carracedo, A., Rodes, A., Smellie, J.L., and Stuart, F.M.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Geomorphology
Publisher:Elsevier
ISSN:0169-555X
ISSN (Online):0169-555X
Published Online:22 November 2018
Copyright Holders:Copyright © 2018 Elsevier
First Published:First published in Geomorphology 327:438-445
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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