A marginal Late Proterozoic ocean basin in the Welsh region

Abstract

SummaryRe-assessment of the idea that the Monian and Longmyndian accumulated along the margin of a palaeo-ocean suggests that Monian sedimentation occurred near the eastern shoreline of a micro-continent. If Monian igneous activity, metamorphism and deformation are attributed to an underlying subduction zone, this must have dipped northwestwards away from a small ocean basin to the southeast. Consumption of this ocean floor brought about collision with the continental shield and simple deformation of the Longmyndian.