Asynchronous glacier dynamics during the Antarctic Cold Reversal in central Patagonia

Davies, B.J., Thorndycraft, V.R., Fabel, D. and Martin, J.R.V. (2018) Asynchronous glacier dynamics during the Antarctic Cold Reversal in central Patagonia. Quaternary Science Reviews, 200, pp. 287-312. (doi: 10.1016/j.quascirev.2018.09.025)

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We present 14 new 10Be cosmogenic nuclide exposure ages quantifying asynchronous readvances during the Antarctic Cold Reversal from glaciers in the Baker Valley region of central Patagonia. We constrain glacier and ice-dammed palaeolake dynamics using a landsystems approach, concentrating on outlet glaciers from the eastern Northern Patagonian Icefield (NPI) and Monte San Lorenzo (MSL). Soler Glacier (NPI) produced lateral moraines above Lago Bertrand from 15.1 ± 0.7 to 14.0 ± 0.6 ka, when it dammed the drainage of Lago General Carrera/Buenos Aires through Río Baker at a bedrock pinning point. At this time, Soler Glacier terminated into the 400 m “Deseado” level of the ice-dammed palaeolake. Later, Calluqueo Glacier (MSL) deposited subaerial and subaqueous moraines in the Salto Valley near Cochrane at 13.0 ± 0.6 ka. These moraines were deposited in an ice-dammed palaeolake unified through the Baker Valley (Lago Chalenko; 350 m asl). The Salto Valley glaciolacustrine landsystem includes subaqueous morainal banks, ice-scoured bedrock, glacial diamicton plastered onto valley sides, perched delta terraces, kame terraces, ice-contact fans, palaeoshorelines and subaerial push and lateral moraines. Boulders from the subaqueous Salto Moraine became exposed at 12.1 ± 0.6 years, indicating palaeolake drainage. These data show an asynchronous advance of outlet glaciers from the Northern Patagonian Icefield and Monte San Lorenzo during the Antarctic Cold Reversal. These advances occurred during a period of regional climatic cooling, but differential moraine extent and timing of advance was controlled by topography and calving processes.

Item Type:Articles
Additional Information:Fieldwork was funded by the Royal Holloway University of London Research Strategy Fund (RHUL-RSF) and NERC DTP PhD award NE/L002485/1 awarded to Martin. We thank the RHUL-RSF, Quaternary Research Association, British Society for Geomorphology, and the Geologists' Association for each part-funding analytical costs of cosmogenic nuclide analysis.
Glasgow Author(s) Enlighten ID:Fabel, Dr Derek
Authors: Davies, B.J., Thorndycraft, V.R., Fabel, D., and Martin, J.R.V.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Quaternary Science Reviews
ISSN (Online):1873-457X
Published Online:10 October 2018
Copyright Holders:Copyright © 2018 The Authors
First Published:First published in Quaternary Science Reviews 200: 287-312
Publisher Policy:Reproduced under a Creative Commons License

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