Age evaluation and causation of rock-slope failures along the western margin of the Antrim Lava Group (ALG), Northern Ireland, based on cosmogenic isotope (36Cl) surface exposure dating

Southall, D. W., Wilson, P., Dunlop, P., Schnabel, C., Rodés, Á. , Gulliver, P. and Xu, S. (2017) Age evaluation and causation of rock-slope failures along the western margin of the Antrim Lava Group (ALG), Northern Ireland, based on cosmogenic isotope (36Cl) surface exposure dating. Geomorphology, 285, pp. 235-246. (doi: 10.1016/j.geomorph.2017.01.041)

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Abstract

The temporal pattern of postglacial rock-slope failure in a glaciated upland area of Ireland (the western margin of the Antrim Lava Group) was evaluated using both 36Cl exposure dating of surface boulders on run-out debris and 14C dating of basal organic soils from depressions on the debris. The majority of the 36Cl ages (~ 21–15 ka) indicate that major failures occurred during or immediately following local deglaciation (~ 18–17 ka). Other ages (~ 14–9 ka) suggest some later, smaller-scale failures during the Lateglacial and/or early Holocene. The 14C ages (2.36–0.15 cal ka BP) indicate the very late onset of organic accumulation and do not provide close limiting age constraints. Rock-slope failure during or immediately following local deglaciation was probably in response to some combination of glacial debuttressing, slope steepening and paraglacial stress release. Later failures may have been triggered by seismic activity associated with glacio-isostatic crustal uplift and/or permafrost degradation consequent upon climate change. The 36Cl ages support the findings of previous studies that show the deglacial - Lateglacial period in northwest Ireland and Scotland to have been one of enhanced rock-slope failure.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Gulliver, Dr Pauline and Schnabel, Dr Christoph and Rodes, Dr Angel and Xu, Dr Sheng
Authors: Southall, D. W., Wilson, P., Dunlop, P., Schnabel, C., Rodés, Á., Gulliver, P., and Xu, S.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Geomorphology
Publisher:Elsevier
ISSN:0169-555X
ISSN (Online):1872-695X
Published Online:27 February 2017
Copyright Holders:Copyright © 2017 Elsevier B.V.
First Published:First published in Geomorphology 285:235-246
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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