Tectonic control of sedimentation at the margin of a Carboniferous depositional basin in Kirkcudbrightshire

Abstract

Synopsis The stratigraphy and sedimentation of the Lower Carboniferous rocks between White Port and Kirkbean, Kirkcudbrightshire have been re-investigated. The sediments fall into two distinct associations (i) light hued, fine-grained carbonate-rich rocks deposited by normal shallow marine and fluviatile agencies and (ii) red beds dominated by coarse conglomerates and deposited predominantly under sub-aerial conditions. Within the red bed association there are at least two large-scale cycles of deposition commencing with coarse alluvial conglomerates, fining upwards into subordinate shallow marine fossiliferous sediments and then coarsening upwards into alluvial conglomerates again. The origin and preservation of these cycles is related to penecontemporaneous activity on a large basin margin fault, possibly aided by late–Caledonian upward movements within the Southern Uplands.