Oscillating retreat of the last British-Irish Ice Sheet on the continental shelf offshore Galway Bay, western Ireland

Callard, S. L. et al. (2020) Oscillating retreat of the last British-Irish Ice Sheet on the continental shelf offshore Galway Bay, western Ireland. Marine Geology, 420, 106087. (doi: 10.1016/j.margeo.2019.106087)

Abstract

During the Last Glacial Maximum, the British-Irish Ice Sheet extended across the continental shelf offshore of Galway Bay, western Ireland, and reached a maximum westward extent on the Porcupine Bank. New marine geophysical data, sediment cores and radiocarbon dates are used to constrain the style and timing of ice-sheet retreat across the mid to inner-shelf. Radiocarbon dated shell fragments in subglacial till on the mid-shelf constrains ice advance to after 26.4 ka BP. Initial retreat was underway before 24.4 ka BP, significantly earlier than previous reconstructions. Grounding-line retreat was accompanied by stillstands and/or localised readvances of the grounding-line. A large composite Mid-Shelf Grounding Zone Complex marks a major grounding-line position, with the ice grounded and the margin oscillating at this position by, and probably after, 23 ka BP. The continental shelf was ice-free by 17.1 cal. ka BP, but the ice sheet may have retained a marine margin until c. 15.3 ka BP. Retreat occurred in a glacimarine setting and the ice sheet was fringed by a floating ice-shelf. Collectively, this evidence indicates a dynamic and oscillatory marine-terminating ice sheet offshore of western Ireland during the last deglaciation.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Moreton, Dr Steven and Fabel, Dr Derek
• Authors: Callard, S. L., Ó Cofaigh, C., Benetti, S., Chiverrell, R. C., Van Landeghem, K. J.J., Saher, M. H., Livingstone, S. J., Clark, C. D., Small, D., Fabel, D., and Moreton, S. G.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Marine Geology
• Publisher: Elsevier
• ISSN: 0025-3227
• ISSN (Online): 1872-6151
• Published Online: 26 November 2019
• Copyright Holders: Copyright © 2019 Elsevier
• First Published: First published in Marine Geology 420:106087
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher