ELSEVIER Palaeogeography, Palaeoclimatology, Palaeoecology 121 (1996) 13-34 PAIAEO Interaction of climate and tectonics upon alluvial architecture: Late Carboniferous-Early Permian sequences at the southern margin of the Pennine Basin, UK Brian W. Glover, John H. Powell British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham, NG12 5GG, UK Received 30 August 1994; revised and accepted 3 May 1995 Abstract Late Carboniferous (mid to late Westphalian D) to Early Permian strata of south Staffordshire, English Midlands were deposited on the margins of a foreland basin (Pennine Basin) during a period of increasing climatic aridity. Approximately 300-500 m of grey and red-bed alluvial sediments contain five vertically stacked facies associations, each with characteristic stratal architecture and palaeosols. The succession exhibits three orders of cyclicity. First order cycles (100-150 m thick) resulted from tectonic activity in the hinterland. Second order cyclicity, reflected in three regionally extensive, dekametre-scale, upward-fining packages resulted from isostatic readjustment of the source area. Third order, autocyclic responses caused metre- to dekametre-scale, upward-fining and upward-coarsening trends. Tectonics and climate were interdependent and their combined effects led to deposition of first order cyclesor sequences. Cycle 1 was deposited largely upon a poorly drained alluvial plain; caliches within the interfluves indicate relatively high evapotranspiration rates. Heavy mineral data suggest a distant source. Cycles 2 and 3 reflect a switch to a local source. This was probably due to the combined effects of hinterland tectonism and increasing aridity. The latter led to fluvial inefficiency and increasing input from local drainage basins. The change in climate and source area resulted in variable sand/mud ratios and depositional styles for each cycle. Recognition of the influence of tectonics and climate in fluvial sedimentation means that the resultant genetic alluvial sequence architecture has a predictive function. In the absence of good biostratigraphical markers, this can be used in correlation and predicting sequence architecture in adjacent areas. 1. Introduction The ongoing search for oil and gas in northern Europe has recently focused attention on Carboniferous prospects and source rocks (e.g. Leeder and Hardman, 1990; Baily et al., 1993; Besly et al., 1993; Collinson et al., 1993; Hollywood and Whorlow, 1993; Quirk, 1993). The application of sequence stratigraphical principles to Namurian and lower parts of the Westphalian strata (Read, 0031-0182/96/$15.00 © 1996 Elsevier Science B.V. All rights reserved SSDI 0031-0182(95)00050-X 1991; Maynard, 1992; Flint et al., 1993; Hampson, 1993; Martinsen, 1993) has resulted in a clearer understanding of possible source and reservoir rocks. For most of the Northern European Carboniferous, however, much of the overlying Westphalian C to ?Stephanian succession appears to have been deposited in a foreland basin setting with little or no connection to the open ocean. Consequently, the direct influence of eustatic or relative sea-level fluctuations on patterns of conti-