Siliciclastic slope deposits from the Cretaceous Abeokuta Group, Dahomey (Benin) Basin, southwestern Nigeria

Outcrops in the Cretaceous Abeokuta Group of the Dahomey (Benin) Basin in southwestern Nigeria are described. Based on detailed sedimentological logging, 13 lithofacies were delineated. They are: massive and loose sand; cross-bedded loose sand; normally graded sandstone (upward fining sandstone); laminated silt; clay; laminated sandstone; clay with sandstone injections and clasts (sandstone boulders); clayey sand with sandstone boulders; silty clay with intraformational folds and breccias; highly contorted conglomerate/clayey silt; and channel infills. The association of the lithofacies and their sedimentary structures support that these lithologies were deposited by turbidity current, grain flow, debris flow, liquefied flow and fluidized flow. Since these depositional features are diagnostic of slope environments, the Cretaceous Abeokuta Group was concluded to have been deposited in slope environments.