Report of a joint meeting of the Tectonic Studies Group and the British Sedimentological Research Group of the Geological Society held at the University College of Wales, Aberystwyth on 10–12 April 1986. The organizers were Dr W. R. Fitches and Dr N. H. Woodcock.
Research into the Early Palaeozoic history of Wales is like that history itself; eventful and rarely quiescent. Recent events have been the lively debate on the tectonics of Anglesey provoked by A. J. Barber and M. D. Max, the exemplary volcanological studies in North Wales by the BGS Snowdonia unit, and the definition of Silurian world stratotypes by members of the Ludlow Research Group. The stimulus for this conference was the recently increased activity in structural and sedimentological research in mainland Wales. Twenty-eight papers were given over the first 2 days, followed by a day of field trips to Snowdonia, the Aberystwyth area, and the Wenlock of eastern Mid-Wales.
Precambrian events featured in three papers. D. S. Wood concentrated on the evidence for the superficial ‘soft-sediment’ origin of the Gwna melange of Anglesey and postulated a setting predating rather than accompanying the subduction system that produced the Anglesey blueschists. In the later deformation history of Anglesey, D. Carter distinguished two main deformations. A Caledonian event was preceded by one of pre-Arenig or probably pre-Arvonian age, with an unconformity present between the Monian and Lower Palaeozoic rocks. Precambrian sedimentation of the Longmyndian of Salop was described by J. Pauley in terms of a progradational basin fill.