Late Cretaceous Palynostratigraphy of Subsurface Sediments of Southern Bornu Basin, Nigeria: Implications For Depositional Environments And Palaeoclimate.

Abstract

Presented in this study are the findings of a cross-examination of the subsurface stratigraphic successions (1500-4600 m) penetrated by the Gaibu-1 well, Bornu Basin, NE Nigeria to understand the palaeoenvironmental settings and the palaeoclimatic conditions of the sediments. Sedimentological/textural description, lithological identification and palynological analysis were carried out using standard laboratory procedures and wireline (gamma-ray and SP) logs. The sediments consist predominantly of sandstone, siltstone, sandy shale, and shale. The sandstones range from fine-coarse, angular to sub-rounded, moderate to poorly sorted, and are texturally immature. Five (5) stratigraphic sub-divisions; the Bima, the Yolde, the Gongila, the Fika (Upper, Middle and Lower members) and the Gombe formations were identified. The palynozonation enabled four distinctive zones: (i) A (1) Triorites africaensis Assemblage Zone, (ii) A (2) Cretacaeiporites scabratus / Odontochitina costata Assemblage Zone, (iii) A (3) Droseridites senonicus Assemblage Zone, A (4) Syncolporites/Milfordia spp. Assemblage Zone. These suggest the well penetrated Cenomanian – Maastrichtian (younger) successions, interpreted to have been deposited in a series of continental to marginal marine environments. The sediments are characterised by palynofloral assemblages that are indicative of a tropical to subtropical climate condition that is warm and humid, which correspond to the late Cretaceous Palmae Province of Africa – Southern America.

Chemostratigraphy of the Cretaceous Yolde Formation in Yola Sub-Basin, Northern Benue Trough, Ne Nigeria

“…By employing chemostratigraphy in this region, the study aim to unravel the complex geological history preserved within the Yolde Formation and contribute to a more comprehensive understanding of the Northern Benue Trough's stratigraphic evolution. Some of the recent works that were carried out on the Yolde Formation are; (Sarki Yandoka et al, 2019;Epuh & Joshua, 2020;Adepehin et al, 2021). This research endeavour is motivated by the need to expand knowledge about the Yolde Formation through a rigorous scientific approach that integrates chemostratigraphy.…”