Dynamics of former ice lobes of the southernmost Patagonian Ice Sheet based on a glacial landsystems approach

Darvill, C.M.; Stokes, C.R.; Bentley, M.J.; Evans, D.J.A.; Lovell, H.

doi:10.1002/jqs.2890

Dynamics of former ice lobes of the southernmost Patagonian Ice Sheet based on a glacial landsystems approach

Darvill, C.M.; Stokes, C.R.; Bentley, M.J.; Evans, D.J.A.; Lovell, H.

Authors

C.M. Darvill

Professor Chris Stokes c.r.stokes@durham.ac.uk
Professor

Professor Michael Bentley m.j.bentley@durham.ac.uk
Professor

Professor David Evans d.j.a.evans@durham.ac.uk
Professor

H. Lovell

Abstract

Reconstructions of former ice masses from glacial geomorphology help to constrain the nature and timing of glaciation in relation to climatic forcing. This paper presents a new reconstruction of the glacial history of five ice lobes in southernmost South America: the Bahía Inútil − San Sebastián, Magellan, Otway, Skyring and Río Gallegos ice lobes. We use previous geomorphological mapping of glacial landforms to reconstruct former glacial limits and proglacial lakes, demarcate flow-sets from the distribution of glacial lineations, and evaluate glacial landsystem signatures and their palaeoglaciological implications. Evidence suggests that the ice lobes predominantly reflect active temperate glacial landsystems, which may have switched to polythermal systems when periods of cold-based ice developed ephemerally. This complex landsystem signature implies that the ice lobes were sensitive to regional climate variability, with active re-advances during overall retreat of the ice margins. There is also evidence for periods of fast ice flow and possible surge-like activity in the region, followed by the rapid retreat or even collapse of some of the ice lobes in association with proglacial lakes. Constraining our new reconstruction with published chronological information suggests that at least some of the ice lobes advanced before the global Last Glacial Maximum (gLGM: ca. 26.5–19 ka) during the last glacial cycle. Our new reconstruction demonstrates a more complex picture of ice dynamics than has previously been portrayed, and one in which the advance and retreat of the ice lobes was likely to have been primarily driven by changes in climate. As such, ice advances before the gLGM in the southernmost part of the Patagonian Ice Sheet are likely to indicate a wider climatic forcing at this time.

Citation

Darvill, C., Stokes, C., Bentley, M., Evans, D., & Lovell, H. (2016). Dynamics of former ice lobes of the southernmost Patagonian Ice Sheet based on a glacial landsystems approach. Journal of Quaternary Science, 32(6), 857-876. https://doi.org/10.1002/jqs.2890

Journal Article Type	Article
Acceptance Date	Jun 26, 2016
Online Publication Date	Sep 16, 2016
Publication Date	Sep 16, 2016
Deposit Date	Jul 14, 2016
Publicly Available Date	Jul 19, 2016
Journal	Journal of Quaternary Science
Print ISSN	0267-8179
Electronic ISSN	1099-1417
Publisher	Wiley
Peer Reviewed	Peer Reviewed
Volume	32
Issue	6
Pages	857-876
DOI	https://doi.org/10.1002/jqs.2890

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Copyright Statement
© 2016 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.