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Two new Ordovician volcanic centres in the Shelve inlier, Powys, Wales

Published online by Cambridge University Press:  01 May 2009

B. D. T. Lynas
B. D. T. Lynas
Affiliation:
Institute of Geological Sciences, Nicker Hill Keyworth, Nottingham NG12 5GG
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Abstract

Summary. As a direct result of new work in the Shelve Ordovician inlier, two new important extrusive andesitic members of a revised Stapeley Volcanic Formation, are described. These members were originally regarded as extrusive. However, they have for over half a century been considered intrusive and a brief literature review attempts to account for this anomaly. A palaeogeographic reconstruction suggests that the members represent the remains of two Llanvirn volcanic islands which, following subsidence, were overlapped and buried by later Llanvirn sedimentation. This reinterpretation considerably increases the volume of andesitic material known to have been erupted in Llanvirn times in this part of the Welsh borderland.

Type
Articles
Information
Geological Magazine , Volume 120 , Issue 6 , December 1983 , pp. 535 - 542
Copyright
Copyright © Cambridge University Press 1983

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