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XVII.—The Major Ultrabasic and Basic Intrusions of St Kilda, Outer Hebrides

Published online by Cambridge University Press:  06 July 2012

R. R. Harding
R. R. Harding
Affiliation:
Department of Geology and Mineralogy, University of Oxford.
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Abstract

The structures and mineralogy of the Tertiary ultrabasic and basic intrusions are described. The ultrabasic rocks are thought to be remnants of a layered intrusion which once extended from Hirta to Boreray, and which probably formed by crystal accumulation. The eucrites may represent higher levels of this intrusion. A 350 feet-thick, fine-grained margin is described from the East Glen Bay Gabbro. The metamorphism of the ultrabasic and eucritic rocks, and the formation of the Glacan Mor Complex, probably occurred in a basic environment, before intrusion of the first acid rocks on St. Kilda. Five major-element and twenty-two trace-element analyses are presented.

Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 66 , Issue 17 , 1967 , pp. 419 - 444
Copyright
Copyright © Royal Society of Edinburgh 1967

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