Provenance and Paleoclimatic assessment of the shales penetrated by Erekiti borehole in the Dahomey basin, Nigeria

Abstract

The shales from the Araromi Formation penetrated by the Erekiti borehole in the Dahomey basin were analyzed for their source area and paleo weathering conditions. Ten (10) samples were subjected to X-ray fluorescence (XRF) and X-ray diffraction (XRD) analyses. The major oxide revealed an abundance of SiO₂ and Al₂O₃ (average 32.81 wt.% and 13.11 wt.% respectively) and depletion of TiO₂, Fe₂O₃, CaO, MgO, and MnO, while the trace elements present includes an abundance of V, Cr, Zr, Sr, Zn, Ba and depletion of Sc, Co, Ni, Cu, As, Rb, Sr, Y, Nb, Mo, Pb, Th, and U. The results shows that the shales are associated to intermediate to felsic igneous origin under a very low weathering intensity. The mineralogical composition reveals quartz, gypsum, and calcite as the most abundant and the presence of other accessory minerals such as Kaolinite, K-feldspar, and plagioclase. The high percentage of quartz and gypsum confirmed the low weathering condition.