Carboniferous geology of Northern England

The British Geological Survey (BGS) has produced a wholesale rationalisation of Carboniferous lithostratigraphical nomenclature. This presentation describes the Carboniferous stratigraphy of northern England, illustrated with research carried out as part of recent BGS mapping projects. During the Tournaisian and Visean a phase of north–south rifting resulted in the development of grabens and half-grabens, separated by platforms and tilt-block highs. Visean marine transgressions resulted in the establishment of platform carbonates, which gradually onlapped raised horst and tilt-block highs. The evolution of one such tilt-block high, the Askrigg block, and associated Great Scar Limestone Group, is described in detail. During late Visean times a cyclic succession of fluvio-deltaic clastics, marine reworked sandstones and shallow-shelf marine carbonates (Yoredale Group) dominated across northern England, terminating deposition of the platform carbonates. To the south of the Craven fault system, which defines the southern margin of the Askrigg Block, the block and basin structures persisted, though generally the high subsidence rates created a province dominated by hemipelagic mudstones and carbonate/siliciclastic turbidites (Craven Group). Cessation of rifting during the late Visean in the area between the Southern Uplands and the Wales–Brabant High resulted in a period dominated by thermally induced regional subsidence during Namurian and Westphalian times, with formation of the Pennine Basin. During early Namurian times fluvio-deltaic systems started to feed siliciclastic sediment into the northern margin of the basin (Millstone Grit Group). Initial deposition in the basinal areas is marked by the formation of thick turbidity-fronted delta successions. By late Namurian times, the southern part of the basin began to be infilled by fluvio-deltaic systems entering the basin from the east and south-east, but ultimately still sourced from the north. Three case studies are described in detail: the Kinderscout Grit, Ashover Grit and Chatsworth Grit. The development of these sand bodies occurred within a regime of regular and marked sea level changes. Evidence will be provided for the duration of this cyclicity. From early in the Westphalian, a coal-forming delta-top environment, associated with formation of the Pennine Coal Measures Group became established across the Pennine Basin. There was gradual waning of the influence of marine flooding events in the basin. The sediment influx into the Pennine Basin progressively changed from a dominantly northern provenance, comparable to the Millstone Grit Group, to initially a western source and subsequently to a southern one, later in the Westphalian