Biostratigraphic Study of the Calcareous Nannofossil of well XH-1, Deep Offshore, Niger Delta, Nigeria.

Abstract

A calcareous nannofossil biostratigraphic study has been carried out on sequences within the well XH-1 located in the deep offshore area of the Niger Delta, Nigeria. Forty-one (41) calcareous nannofossil species identified were used to make biostratigraphic deductions including zonation, dating and a tentative sequence stratigraphic framework for the intervals studied.
Two major nannofossil zones (NN11 and NN10 / CN9 and CN8) belonging to the Late Miocene age were identified following the standard zonation schemes.
Three major zones of Discoaster quinqueramus zone, Discoaster berggrenii zone, and Discoaster bollii zone, were erected for this well based on the index taxa and fossil assemblage recorded. Discoaster berggrenii zone was further subdivided into two subzones. Based on the lithostratigraphic studies, the sediments reveal hemipelagic shale with traces of sand at the lower half of the well.
Nannofossil abundance/diversity patterns calibrated with chronostratigraphically vital bioevents reveals three (3) Condensed Sections as correlated to the Global Cycle Chart. This is associated with the 5.8 Ma, 7.0 Ma and 9.2 Ma Maximum Flooding Surfaces.


Journal of Mining and Geology Vol. 43 (2) 2007: pp. 175-186