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The Wolf Rock, Cornwall: new chemical, isotopic age and palaeomagnetic data

Published online by Cambridge University Press:  01 May 2009

R. K. Harrison,
N. J. Snelling,
R. J. Merriman,
G. E. Morgan and
A. J. J. Goode
R. K. Harrison
Affiliation:
Institute of Geological Sciences, Exhibition Road, London SW7 2DE
N. J. Snelling
Affiliation:
Institute of Geological Sciences, Gray's Inn Road, London WC1X 8NG
R. J. Merriman
Affiliation:
Institute of Geological Sciences, Exhibition Road, London SW7 2DE
G. E. Morgan
Affiliation:
Department of Earth sciences, The University, Leeds 2
A. J. J. Goode
Affiliation:
Institute of Geological Sciences, Hoopern House, 101, Pennsylvania Road, Exeter, EX4 6DT
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Summary

By systematic sampling (including the drilling of orientated cores) new data are presented on the chemistry, petrography, mineralogy, K/Ar isotopic age and remanent magnetism of the Wolf Rock, Cornwall. The overall homogeneity of the Rock is confirmed as a fine-grained fluxioned microporphyritic phonolite. Major joints strike NNW–SSE and NNE–SSW and there is a pronounced floor jointing. New whole-rock and probe analyses of the constituent minerals are given. Nosean, previously recorded, is found to be replaced by analcime, cancrinite and other minerals. K–Ar determinations on nepheline and K-feldspar give mean ages of 112±2, and 130±6 Ma respectively. The mean pole position of 70° N, 6° E, suggests that the 130 Ma pole for stable Europe may have been somewhat closer to Europe than previously supposed. The significance of this Lower Cretaceous magmatism in the context of Mesozoic volcanism in Southern England and European alkaline provinces is discussed.

Information

Type
Articles
Information
Geological Magazine , Volume 114 , Issue 4 , July 1977, pp. 249 - 264
Copyright
Copyright © Cambridge University Press 1977

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