On the timing of retreat of the Loch Lomond (‘Younger Dryas’) Readvance icefield in the SW Scottish Highlands and its wider significance

Lowe, J., Matthews, I., Mayfield, R., Lincoln, P., Palmer, A., Staff, R. and Timms, R. (2019) On the timing of retreat of the Loch Lomond (‘Younger Dryas’) Readvance icefield in the SW Scottish Highlands and its wider significance. Quaternary Science Reviews, 219, pp. 171-186. (doi:10.1016/j.quascirev.2019.06.034)

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Abstract

It has long been assumed that the last glacier expansion in the Scottish Highlands, the Loch Lomond Readvance (LLR), resulted from a cold reversal that was broadly coeval with the ‘Younger Dryas’ episode. This view has recently been challenged, with the suggestion that glacier ice had disappeared from Rannoch Moor, one of the main ice accumulation centres in the SW Scottish Highlands, by as early as 12.5 ka, i.e. within the first half of the ‘Younger Dryas’. Here we present new radiocarbon, tephrostratigraphical and pollen-stratigraphical evidence from one of the key sites on Rannoch Moor, the results of an experiment designed to test this hypothesis. Our results not only contradict that concept, but are fully compatible with other evidence from the SW Scottish Highlands that suggests that the LLR glaciers in this area continued to expand until towards the end of the ‘Younger Dryas’ period, and may have persisted in some places after the onset of the Holocene. We consider the possible reasons for this marked divergence in chronology, a matter that is crucial to resolve because the precise timing of the demise of the LLR glaciers has important palaeoclimatic and other implications. In the wider context, we also draw attention to problems with the general use of the term ‘Younger Dryas’ and why we regard the Greenland stratotype unit and term ‘Greenland Stadial 1’ (GS-1) a more secure stratigraphic comparator.

Item Type:Articles
Additional Information:JL gratefully acknowledges financial support from The Leverhulme Trust (Emeritus Fellowship project EM-2014-025) which facilitated the field investigations and the procurement of the radiocarbon measurements reported herein, and the granting of access to the Kingshouse site by Mr. Graeme Ferguson of Bidwell’s, Fort William, and by Scottish Natural Heritage (South Highland Fort William office). This study is a contribution to the INTIMATE programme (‘INTegrating Ice-core, MArine and TErrestrial records for the period 60,000 to 8000 years ago’: http://intimate.nbi.ku.dk).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Staff, Dr Richard
Authors: Lowe, J., Matthews, I., Mayfield, R., Lincoln, P., Palmer, A., Staff, R., and Timms, R.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Quaternary Science Reviews
Publisher:Elsevier
ISSN:0277-3791
ISSN (Online):1873-457X
Published Online:20 July 2019
Copyright Holders:Copyright © 2019 Crown Copyright
First Published:First published in Quaternary Science Reviews 219: 171-186
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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