Original paper

A Viséan (Brigantian) conodont assemblage preserved in the dissolution residue component of a breccia matrix at Bullslaughter Bay, Pembrokeshire, South Wales

Błażejowski, Błażej; Walsh, Peter

Abstract

This paper presents the results of a systematic investigation of breccia matrices from the so-called Gash Breccias of southern Pembrokeshire, South Wales. The investigation has revealed a Viséan (Brigantian) conodont assemblage preserved in the dissolution residue of a limestone breccia at Bullslaughter Bay East. The assemblage comprises eleven taxa including eight genera. Field evidence for its age suggests that the assemblage is derived from either the Asbian Oxwich Head Formation or the Brigantian Oystermouth Formation. The faunal assemblage, however, includes Vogelgnathus aff. postcampbelli, which is not known in the Asbian. It is, thus, certain that the source of the assemblage was Brigantian and the absence of Lochriea nodosa, L. mononodosa and L. ziegleri indicates that the source was probably from lower part of the Brigantian. The bearing of the assemblage on the age and origin of these controversial breccias is discussed. It is concluded that, at modern exposure levels, the Gash Breccias have always been devoid of microfossils indicative of the age of the brecciation.

Keywords

visÉan (brigantian)conodontsbiostratigraphygash brecciawales