Omoboriowo, A. O., Soronnadi-Ononiwu,C. G, Awodogan, O. L.
The biostratigraphy of stratigraphic sections exposed at Agbogugu along the Port Harcourt – Enugu Expressway was studied and some key evaluations were reached. The stratigraphic section (The Enugu Shale) is one of the Campanian – Maastrichtian successions of the Anambra Basin, Southeastern Nigeria. It is located at latitude 60151N and longitude 70211E of Greenwich Meridian. The lithologic units of the succession are basically shales with ironstone intercalation showing a likely marine depositional environment. The method of study involved the collection of sample to evaluate the final subsequent laboratory analysis of collected sample to evaluate final observable features. A total of nine (9) samples were collected from this outcrop. From the laboratory analysis carried out, a lithological description of all samples collected depth by depth was made with 2.0m HCI to check the presence or absence of calcareous forms. A sand/shale ratio plot was made from the wet sieve analysis and an approximate percent of sand and shale were interpreted. The result shows more shales than sand in the sediment showing a marine origin of deposition. Also from micropaleontological analysis made, 6 diverse forms of benthic arenaceous foraminifera assemblages were recovered. They are; Ammobacultiesamabensis, Haphragmoides saheliense, Siroplectammina hausorum textularia gilbedina, Ammobaculities sp and Haplophragmoldes sp. They are the benthic and their ages span from campanian to maastrichtian which coincides with the marine incursion in the Anambra Basin. These forms suggest a coastal swamp, tidal flat to estuarine, delta front to inner neritic environments of deposition.
