Palynostratigraphy of Early Cretaceous Sedimentary Deposits from the Rio del Rey Basin, S.W. Cameroon

Abstract

A Mid Albian-Cenomanian age has been assigned to the outcrop section along River Mesambi in the northeastern part of the Rio del Rey Basin on the basis of a palynofloral assemblage that include amongst others: Ephedripites jansonii, E. montanaensis, E. subtilis, Steevesipollenites giganteus and S. binodosus. This assemblage is comparable with previously established Early Cretaceous microflora from elsewhere. The total recovery is poor to only fair and could not be subjected to normal rigorous statistical analysis. Inference of the paleoenvironment of deposition was aided by the observed lithofacies. Important hydrocarbon source rocks have been described only from the Tertiary offshore portion of this basin. Recent discovery of oil and gas in some age equivalent onshore sediments in other West African Marginal basins; northern part of the Tano Basin in Ghana and Anambra Basin in Nigeria respectively has initiated investigations of the Cretaceous black shales onshore of the Rio del Rey Basin in Cameroon. Outcrops are generally very scarce however River Mesambi has unusually exposed a 32m sequence of dark gray to black, highly indurated shales, intercalated in places by thin limestone beds. The present study will contribute to the biostratigraphic data absolutely required towards the build up of the Cretaceous lithostratigraphy and the search for hydrocarbon in the Rio del Rey Basin.

Keywords: Assemblage, Early Cretaceous, Paleodepositional environment, Palynoflora, Rio del Rey

JOURNAL OF THE CAMEROON ACADEMY OF SCIENCES Vol. 11 No. 1 (2013)