The Carboniferous geology of northern Donegal Bay

Abstract

New geological mapping, along with sedimentological and microfaunal analysis, has enabled correlation among three disparate outcrops of early Carboniferous rocks on the north side of Donegal Bay. This area represents the northernmost exposures of the Carboniferous in north-west Ireland and is inferred to have lain close to the Visean shoreline. A regionally traceable marine flooding event at the base of the Bundoran Shale approximately coincides with the base of the Arundian Stage. Below this, marginal-marine successions can all be assigned to the Lower Visean based on microfaunas. These successions display a lower, non-marine clastic sequence that passes gradationally upward into a shallow-marine carbonate-dominant sequence. This sequence is succeeded by a regressive event that is regionally correlateable despite lateral variation in facies.