Nature of the Campano-Maastrichtian Sub-Basins in the Gongola Basin, Nigeria
Geological mapping was carried out and outcrop sections were examined alongside palaeocurrent directions from the greater part of the Campano-Maastrichtian outcrops in the Gongola Basin in Nigeria. Palaeocurrent measurements were obtained from asymmetrical ripples, cross bedding and dune bedforms within the channel-filling sub-facies of the Arowa Formation, and the foresets of the tabular cross bedding displayed in the Duguri formation. A north-westerly to a northerly paleocurrent direction was determined for the Arowa formation, indicating that the open sea was located to north-north-west, while a unimodal palaeocurrent directions characterize the Duguri Formation. These currents transported sediment into the Dukku, Akko and Bashar sub-basins with an overall centripetal pattern. The main structural features of the western part of Gongola Basin from E-W, are the N-S, NE-SW and NW-SE trending faults. These series of faults controll the basin subsidence and deposition of the Campano-Maastrichtian succession in the Dukku, Akko and Bashar sub-basins.The lateral and vertical facies variation within the Campano-Maastrichtian succession are in consistence with the northerly retreat of the sea.
Keywords: Campano-Maastrichtian, sub-basin, palaeocurrent, rip-currents.