Tectono-sedimentary evolution of the Bowland Basin, N England, during the Dinantian

Abstract

The Bowland Basin is a NE–SW-trending sedimentary basin, lying between the Askrigg–Bowland High to the N and NW and the Central Pennine High to the SE. The basin was initiated in ? late Devonian–Tournaisian times. Sediment thickness and facies variations within the Dinantian succession show marked asymmetry on both a basin-wide and intra-basin scale, as a result of approximate NW–SE to N–S extension across normal faults. Thickening of the sedimentary sequence from NE to SW over much of the basin resulted from fault-controlled extension along the SE margin of the basin with downthrow to the NW, giving the basin a half-graben character. Extension occurred in two distinct episodes, marked by basin-wide debris flow and sedimentary slide/slump deposits. During the late Chadian/early Arundian the simple half-graben became modified by a series of NE–SW-trending antithetic and NW–SE-trending transfer faults associated with local unconformities and marked lateral thickness and facies variations. This interval marks the transition from carbonate ramp to slope sedimentation and a temporary halt in carbonate supply to the basin. The second episode of extension, the late Asbian/early Brigantian, marks the break up of the northern basin margin, ending major carbonate deposition within the basin. Reactivation of these structures at the end of the Carboniferous created the Ribblesdale Fold Belt as a result of NW–SE to N–S compression/transpression. Application of this research to areas surrounding the Bowland Basin has led to the recognition of additional shelf basins, the orientation of which suggests control by normal and transfer fault systems. Discussion and