New age constraints for the limit of the British-Irish Ice Sheet on the Isles of Scilly

Smedley, R.K., et al. (2017) New age constraints for the limit of the British-Irish Ice Sheet on the Isles of Scilly. Journal of Quaternary Science, 32(1), pp. 48-62. (doi:10.1002/jqs.2922)

Smedley, R.K., et al. (2017) New age constraints for the limit of the British-Irish Ice Sheet on the Isles of Scilly. Journal of Quaternary Science, 32(1), pp. 48-62. (doi:10.1002/jqs.2922)

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Abstract

The southernmost terrestrial extent of the Irish Sea Ice Stream (ISIS), which drained a large proportion of the last British–Irish Ice Sheet, impinged on to the Isles of Scilly during Marine Isotope Stage 2. However, the age of this ice limit has been contested and the interpretation that this occurred during the Last Glacial Maximum (LGM) remains controversial. This study reports new ages using optically stimulated luminescence (OSL) dating of outwash sediments at Battery, Tresco (25.5 ± 1.5 ka), and terrestrial cosmogenic nuclide exposure dating of boulders overlying till on Scilly Rock (25.9 ± 1.6 ka), which confirm that the ISIS reached the Isles of Scilly during the LGM. The ages demonstrate this ice advance on to the northern Isles of Scilly occurred at ∼26 ka around the time of increased ice-rafted debris in the adjacent marine record from the continental margin, which coincided with Heinrich Event 2 at ∼24 ka. OSL dating (19.6 ± 1.5 ka) of the post-glacial Hell Bay Gravel at Battery suggests there was then an ∼5-ka delay between primary deposition and aeolian reworking of the glacigenic sediment, during a time when the ISIS ice front was oscillating on and around the Llŷn Peninsula, ∼390 km to the north.

Item Type:Articles
Additional Information:This paper was supported by a Natural Environment Research Council consortium grant (BRITICE-CHRONO NE/J008672/1).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Small, Dr David and Gheorghiu, Dr Delia and Xu, Dr Sheng and Fabel, Dr Derek
Authors: Smedley, R.K.,, Scourse, J.D., Small, D., Hiemstra, J.F., Duller, G.A.T., Bateman, M.D., Burke, M.J., Chiverrell, R.C., Clark, C.D., Davies, S.M., Fabel, D., Gheorghiu, D.M., McCarroll, D., Medialdea, A., and Xu, S.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Journal of Quaternary Science
Publisher:Wiley
ISSN:0267-8179
ISSN (Online):1099-1417
Published Online:06 January 2017
Copyright Holders:Copyright © 2017 The Authors
First Published:First published in Journal of Quaternary Science 32(1):48-62
Publisher Policy:Reproduced under a Creative Commons License

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