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St Audrie's Bay, Somerset, England: a candidate Global Stratotype Section and Point for the base of the Jurassic System

Published online by Cambridge University Press:  01 May 2009

G. Warrington
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K.
J. C. W. Cope
Affiliation:
Department of Geology, University of Wales College of Cardiff, P.O. Box 914, Cardiff CF1 3YE, U.K.
H. C. Ivimey-Cook
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K.

Abstract

In 1967 the Somerset coastline near Watchet was proposed as the type area of the basal (Planorbis) chronozone of the Hettangian Stage and thus of the Jurassic System. Neither at that time nor subsequently, however, has a type locality and section been nominated from those available in the area. There is urgent need to select a Global Stratotype Section and Point (GSSP) for the base of the Hettangian, and of the Jurassic System. The cliff forming the headland at the west side of St Audrie's Bay, three kilometres east of Watchet, Somerset, is here proposed as the type locality and section, with the base of the Hettangian Stage, at the base of the Planorbis Chronozone, being placed at the horizon currently recognized as that at which ammonites of the genus Psiloceras appear. In this section the base of the Planorbis Chronozone corresponds with the base of the Psiloceras planorbis Biozone. The proposal of this section is conditioned by the availability of comprehensive litho- and biostratigraphic information, and the ability of the section to fulfil International Commission on Stratigraphy (ICS) requirements for a candidate GSSP.

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Articles
Copyright
Copyright © Cambridge University Press 1994

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