Foraminifera Biozonation of Wells “Amama-1 Well” and “Bara-1 Well” of The Campanian – Maastritchian Ages in the Anambra Basin

Abstract

The study aims at Delineation of Biostratigraphic Zones based on recovered index fossils and/or diagnostic fossil assemblages of sedimentary strata penetrated by Wells “Amama-1 Well” and “Bara-1 Well” of the Campanian – Maastritchian ages of the Anambra Basin. . The two study wells are located in the Anambra Basin with geographic co-ordinates of latitudes 6°10ʹ to 6°22ʹN and longitude 7°02ʹ to 7°16ʹ E. The scope of this study involves the evaluation of the Well analysis and biostratigrapical analysis of the samples. It covers an area of the Nkporo Group from Abia, Nkporo, Ajali and Mamu, Agbogwugwu, Enugu, Emene and Ikem-Uruaram in Enugu State. The results of the Biostratigraphic study have shown that the sediments encountered in the analysed intervals of Wells A and B penetrated the Late Campanian through Late Maastrichtian to Early Paleocene (Danian) age. Two biozones were recognized from Well A namely: Biozone A-Globotruncanella havanensis zone: Late Campanian – Maastrichtian (695 – 1829m), Biozone B-Morozovella velascoensis zone:Early Paleocene (165 – 695m), while three biozones were recognized from Well B belonging to Biozone A-Globotruncanella havanensis zone: Late Campanian (1512m), Biozone B-Bolivinaafra, B. explicate zone: Maastrichtian (634 – 1204m), Biozone C- Indeterminate (305 – 634m). Paleoenvironmental interpretation of the sections of the Anambra Basin penetrated by the study wells indicated that the sediments were deposited in Non-Marine to Outer Neritic paleo-water depths as flood plain, distributary channel, interdistibutary bay as well as Distal bay facies.