(Lack of) sedimentary evidence for the glaciation of Lundy Isle

Carr, Simon and Hiemstra, John (2015) (Lack of) sedimentary evidence for the glaciation of Lundy Isle. Quaternary Newsletter, 135 . pp. 43-47.

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Abstract

Lundy Isle lies at a key position for understanding the last glaciation of the British Isles, as it is directly east of the Irish Sea palaeo-ice stream that extended to the Scilly Isles (Hiemstra et al., 2006) and south of the reconstructed limit of ice extending into the Bristol Channel from Wales (e.g. Hiemstra et al., 2009). It is surprising therefore to note that until recently Lundy Isle has received scant attention in terms of glacial geomorphology, with only brief speculative notes of possible glacigenic sediments and landforms in the north of the island reported by Mitchell (1968) and a related note from Taylor (1974).

A recent investigation by Rolfe et al. (2012) presents a geomorphological map and exposure age-dates from which it is suggested Lundy Isle was completely inundated by an ice sheet during the last glaciation. Exposure-age dates are used to suggest earlier glaciation of Lundy than elsewhere in South Wales or the Irish Sea basin (McCarroll et al., 2010), and that the island was ice-free or beneath cold-based ice at the time of the maximum extent of the Irish Sea ice stream. This has major implications for understanding the geometry, dynamics and timing of ice sheet development during the last glaciation in the southwestern British Isles. Rolfe et al. (2012) base their interpretation of glaciation of Lundy primarily on the description of glacial erosional landforms, glaciallytransported boulders and meltwater channels. Small sheets of diamicton were noted at locations across the island, but were not described or interpreted in their work.

The aim of this project was to describe and sample the diamictons identified by Rolfe et al. (2012) to extract sedimentological and micro-scale (thin section, X-ray CT) information, assuming that at least some of the diamictons are glacigenic. Fieldwork was undertaken in September 2014 as a reconnaissance trip to explore the future potential for further glacial research on Lundy Isle.

Item Type: Article
Journal or Publication Title: Quaternary Newsletter
Publisher: Quaternary Research Association
ISSN: 0143-2826
Departments: STEM
Depositing User: Anna Lupton
Date Deposited: 15 Mar 2019 12:50
Last Modified: 15 Mar 2019 12:51
URI: http://insight.cumbria.ac.uk/id/eprint/4551

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