The geology of the Qinetiq/Ministry of Defence firing range at Aberporth, Ceredigion : part of 1:25 000 sheet SN25

Abstract

The Aberporth firing range is exclusively underlain by upper Ordovician (Ashgillian) mudstones of the Nantmel Mudstone Formation. The rocks dip uniformly to the north-west and comprise the northern limb of a regional anticline (upfold) in the Nantmel Mudstone formation, the axis of which trends south-west to north-east through Parcllyn. A minor splay of the Ceibwr Bay Fault crosses the south-eastern corner of the range, being exposed by the sea cliffs in Cribach Bay. No quaternary (glacial) deposits were identified by the survey, and rockhead appears commensurate with the ground surface across the greater part of the range estate. The Gwrddon valley, to the south-west of the site, may have originated as a meltwater channel excavated beneath an ice-sheet during the last Ice Age