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GEOREF RECORD

Deglaciation and neotectonics in SE Raasay, Scottish Inner Hebrides

David E. Smith, Callum R. Firth, Tim M. Mighall and Phill A. Teasdale
Deglaciation and neotectonics in SE Raasay, Scottish Inner Hebrides
Scottish Journal of Geology (May 2021) 57 (2)

Abstract

Changes in the physical landscape of SE Raasay at the end of the last Quaternary glaciation are examined. The area is marked by a major fault system defining the Beinn na Leac Fault Block, and field survey shows this to comprise a rollover anticline in the SW, with extensional movement towards the NE along an oblique transfer fault, the Main Beinn na Leac Fault. The fault system was reactivated after the Last Glacial Maximum (the LGM). Survey of a distinctive ridge of detached scree along the Main Beinn na Leac fault shows it to have involved a single movement of at least 7.12 m vertical displacement, arguably the greatest fault movement since before the Younger Dryas in Scotland. The present work confirms that the scree became detached during the Younger Dryas, but finds that it overlies a lacustrine deposit of at least 5.6 m of laminated sediments from a lake which had begun to accumulate earlier. Radiocarbon dating of peat overlying the lake sediments gave 10,176 - 10,315 cal. BP, but morphological and stratigraphical evidence indicates that drainage of the lake occurred earlier and only shortly before movement of the scree. Possible causes of displacement at the fault system are briefly discussed.


ISSN: 0036-9276
EISSN: 2041-4951
Coden: SJGEAX
Serial Title: Scottish Journal of Geology
Serial Volume: 57
Serial Issue: 2
Title: Deglaciation and neotectonics in SE Raasay, Scottish Inner Hebrides
Affiliation: University of Oxford, School of Geography and the Environment, Oxford, United Kingdom
Published: 20210518
Text Language: English
Publisher: Geological Society Publishing House for the Geological Societies of Edinburgh and Glasgow, Bath, United Kingdom
References: 38
Accession Number: 2021-049110
Categories: GeomorphologyStructural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. col., 4 tables, geol. sketch map
N57°19'60" - N57°30'00", W06°04'60" - W05°58'60"
Secondary Affiliation: Canterbury Christ Church University, GBR, United KingdomUniversity of Aberdeen, GBR, United KingdomUniversity of Brighton, GBR, United Kingdom
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 202134
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