Evolution and Subsidence of the Bida Basin

Abstract

Basement subsidence and geological formations’ burial history are reconstructed for the Bida Basin, using hypothetical well-site stratigraphy extrapolated from geological formations’ thickness data obtained from outcrops. Lateral displacement of the basin is also reconstructed and the hydrocarbon generation status of its argillaceous sediments is evaluated from estimated time-temperature index (TTI) and Vitrinite reflectance (Ro) values. The basement subsidence curve is identical with the burial curve for oceanic crust and continental drift basins, thereby linking the basin’s genesis and evolution with plate tectonics. The basin evolved from a rift that was created as Abakaliki-Benue Fold Belt developed in response to the tectonic pulse arising from the collision between W est – African Plate and Central African between 85 Ma and 80 Ma. The sea transgressed from the Gulf of Guinea into the basin in Upper Maestrichian to deposit Enagi and Agbaja Formations. The transgression terminated in the central portion of the basin. The estimated maximum temperature attained by the source rock is 26℃. Estimated cumulative-time-temperature index is 0.225 and its corresponding vitinite reflectance is 0.3 %. The source rocks have not experienced catagenesis.