The documentation of a latest Jurassic-earliest Cretaceous uplift throughout southern England and adjacent offshore areas

Abstract: The development of the Wessex Basin, Celtic Sea Basins and the Western Approaches Trough was initiated during the break-up of Pangea with active subsidence continuing throughout he Mesozoic until the basins were inverted in the Tertiary. The Mesozoic stratigraphy in these basins is characterized bya number of unconformities. In the Early Cretaceous two major erosional events can be identified, one in the Berriasian and the second in the Aptian. These unconformities have a significant bearing on both the Cretaceous stratigraphy and the hydrocarbon potential in the region. Stratigraphic data from onshore xposures in the Wessex Basin, from over 100 boreholes, and seismic data document the evolution and erosion pattern of both unconformities. The Aptian unconformity has been well documented byprevious authors, and may be related to uplift associated with commencement of sea-floor spreading in the Bay of Biscay. However, an older unconformity can be identified as Berriasian in age on the basis of tracing its correlative conformity using vertical and lateral facies changes and a rapid lateral increase in the thickness of the Wealden Group. This older unconformity is herein interpreted to have been formed by a latest Jurassic--earliest Cretaceous uplift event and can be recognized inal