A new lithostratigraphic profile for Cretaceous to Paleogene successions in the West and Central African Rift System, Koum Basin, northern Cameroon

Abstract

Six new formations (Gaba, Roumi, Poula, Mbissiri, Lende andKali) are proposed for Cretaceous to Paleogene sediments of the Koum Basin, northern Cameroon. The Koum Basin is one of numerous sedimentary basins lining the West and Central African Rift System and presents a complex evolutionary history involving extensional shearing and compressional events spanning the Cretaceous to Paleogene. Recent discoveries of hydrocarbons in associated basin such as Doba in Chad,motivated exploration of the Koum Basin. However, existing studies of the Koum Basin lack a viable lithostratigraphic framework, which is crucial for ongoing exploration efforts in this basin. The present study integrates lithologic, petrographic and palaeontologic data to map, stack and correlate several outcrop sections across the basin. Facies analysis suggests that deposition occurred in a fluvio-lacustrine palaeodeposional environment. The new units were described following the guidelines of the International Stratigraphic Guide. An updated geologicmap depicts the spatial distribution of the lithostratigraphic units that make up the Koum Basin. Palynomorphs, bivalves and dinosaur footprints are used to date the studied sections.