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By late Devonian times, rifting had begun in northern England with sedimentation occurring in incipient half graben under an arid climate. The remnant Caledonian mountain belt to the north acted as a major sediment source (e.g. Gilligan 1920; Leeder 1988; Gawthorpe et al. 1989) and, in the study area, Caledonian structures were reactivated and also acted as local sediment sources. The northward drift of European Pangaea during the Dinantian led to a change to humid climatic conditions by the late Dinantian (Duff, 1980). This, together with regional transgression, caused a change from red-bed style deposition to fluvio-deltaic deposition in the north of the area, close to the major sediment source, and predominantly carbonate depositional systems in the south of the area, particularly on footwall highs starved of clastic sediment. The development of highfrequency cyclicity in late Dinantian times (e.g. Walkden 1987; Leeder & Strudwick 1987) signifies the growing importance of glacio-eustasy as a control on stratigraphic development; a control which became dominant in the Silesian.
There is general agreement that northern Britain occupied an equatorial position during the Namurian (Scotese et al. 1979; Smith et al. 1981), and the occurrence of coal and bauxitic soil horizons in Scotland indicates a humid, tropical climate (Cope et al. 1992). The increasing rainfall, and associated increase
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