IJLTEMAS International Journal of Latest Technology in Engineering, Management & Applied Science (IJLTEMAS) IJLTEMAS 2278-2540 IJLTEMAS 299 10.51583/IJLTEMAS.2026.150800105 Education Biostratigraphy and Paleoenvironmental Assessments of Upper Cretaceous¬-Lower Tertiary Sediments from the T-Well, Eastern Dahomey Basin, South Western Nigeria. Joshua Olalekan Afolami-Akerekan Department of Geology and Mineral Sciences, University of Ilorin, P. M. B., 1515, Ilorin, Nigeria. Nigeria Olabisi Adeleye Adekeye Department of Geology and Mineral Sciences, University of Ilorin, P. M. B., 1515, Ilorin, Nigeria. Nigeria Olusegun Akande Samuel Department of Geology and Mineral Sciences, University of Ilorin, P. M. B., 1515, Ilorin, Nigeria. Nigeria 15 8 1443 1457 04 09 2026 09 09 2026 19 09 2026 Dahomey Foraminifera Biostratigraphy Paleoenvironment. Abstract

Ditch cuttings of shale, siltstone and sandstone sediments penetrated by the offshore T-well in the Eastern Dahomey Basin, Southwestern Nigeria were studied to establish the Biostratigraphy and Paleoenvironment of the successions. The Siltstones are at the base of the well and overlain by shales and sandstones at the top. The Total depth of the well is approximately 2400m. Twenty shale samples were selected from the well at intervals between 1088m to 2280m for foraminifera study. The results from foraminiferal analysis show a total of 145 foraminifera species; including 125 benthonic and 20 planktonic species. Three major biostratigraphic zonation include: Globotruncanella petaloidea, Morozovella angulata and Acrinina soldadoesis zones were recognized which indicated the Late Cretaceous to Early Eocene age. Some of the Benthic foraminifera species include: Bolivina afra, Bolivina sp, Cibicides sp,Gavelinella sp, Lenticulia sp, Lagena sp,Bulimina sp, Anomalina sp, Eponides sp, Nonionella sp, Textularia sp, Anomalinoids sp, Gavelinella sp, Dentalina sp, Neobulimina sp, Gyroidina sp,Nodosarella sp, Dorothia sp, Anomalina sp, Neorotalina sp, parasubbotina sp with dominant arenaceous species. The Paleoenvironmental interpretation suggest shallow marine anoxic to dysoxic conditions due to the presence of high benthonic foraminifera species and some diagnostic benthonic species.

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