Insights into the early evolution of the Cote d'Ivoire margin (West Africa)

A tectono-stratigraphic analysis of a broadband 3D seismic survey over the outer slope of Cote d'Ivoire margin, west Africa, revealed that Cenomanian and younger strata seal well-developed rift fault blocks up to 15 km across. Growth strata indicate that these were formed during rifting that culminated in seafloor spreading in the late Albian, challenging existing plate reconstructions for the opening of the equatorial Atlantic ocean. A previously unrecognized system of volcanic edifices linked at depth to a network of sill complexes has also been identified. These are aligned along a NE-SW trend, concordant with kilometre-wide ridges, interpreted as folds formed by steep, crustal faults with an oblique-slip component. These trends are similar to those of fracture zones in the region and indicate that the Cote d'Ivoire was a transform margin in the late Albian. These results highlight the potential of offshore Cote d'Ivoire for deep-water rift plays with large traps formed by extensional fault blocks together with prospective Albian reservoirs ponded in their hanging walls. In addition, the volcanoes and ridges generated seabed relief along the newly created transform margin, forming confined basins for potential deposition of Turonian and younger turbidites and the generation of stratigraphic traps.