A gamma-ray correlation of boreholes and oil wells in the Bathonian Stage succession (Middle Jurassic) of the Wealden Shelf subcrop

An analysis of the gamma-ray logs of some forty-three oil wells and boreholes in Sussex and Hampshire demonstrates that the Middle Jurassic (Bathonian) succession at depth there is an extension of the corresponding Cotswold Shelf succession at outcrop in Gloucestershire and the western part of Oxfordshire. The latter extends from the margin of the London Platform landmass to the edge of the Worcester Basin and is characterised by facies belts that prograded basinwards in time. In most respects the Wealden succession replicates the stratigraphy of the Cotswolds Shelf and also exhibits a similar progradation of facies belts from the London Platform landmass to the margin of the contiguous Wessex Basin. The current stratigraphical nomenclature of the Wealden Shelf is reviewed and adjustments to it are introduced to harmonise with that of the Cotswolds Shelf.