The Cenomanian hiatus in the Southern Benue Trough, Nigeria

Abstract

AbstractBasal Turonian Ezeaku Sandstone ridges along the Cenomanian hiatus in Afikpo area contain sandstone pebbles, cobbles, and boulders randomly distributed in nearly all the coarsening upward subfacies of the host units. Contacts with the host sandbody are sharp and, in places, lined with solution grooves. Generally, the angular to subrounded clasts have their 2 mm rims ferruginized, are fine to coarse grained and very strongly bioturbated. They are compositionally and texturally more similar to the adjacent Albian Asu River Group sandunits. These characteristics suggest an extrabasinal origin for these marine sandstone clasts. Albian Asu River Group sediments uplifted by the Cenomanian deformation are the most likely source. The general absence of similar clasts towards the eastern palaeostrandline where the primary Cretaceous source rocks lay is consistent with the interpretation. The remarkable parallelism between the trend of the clast outcrops and the axis of the Santonian anticlinorium (NE–SW) suggests the same axial direction for both tectonic phases.