The global Devonian, Carboniferous and Permian Correlation Project: a review of the contribution from Great Britain

A contribution on the lithostratigraphy and palaeoenvironments of Devonian, Carboniferous and Permian successions onshore in Great Britain, prepared for an international project, is summarised with particular reference to south-west England. Devonian and Carboniferous successions present in that region occur in the Rhenohercynian Tectonic Zone, to the south of the Variscan Front (VF), and their complexity reflects formation in six composite basins. They differ substantially from contemporaneous successions north of the VF. Whereas Devonian successions south of the VF are largely marine, those to the north are continental. Carboniferous successions south of the VF are predominantly marine, but shallow-water and deltaic facies occur in the highest formations. North of the VF, marine conditions were superseded by paralic and continental sedimentation. Erosion, following Variscan tectonism, resulted in the Permian successions generally resting unconformably upon older Palaeozoic rocks. In southwest England a continental succession may extend, with depositional hiatuses, from the latest Carboniferous to the Late Permian and is the most complete Permian succession in Great Britain. However, the position of the Permian–Triassic boundary in the south-west, and elsewhere in the country, is not yet resolved.