Provenance and weathering history of the maastrichtian shale member of the Patti Formation, southern Bida Basin, Nigeria

The present study is focused on the geochemical characterization and provenance of the shale member of the Maastrichtian Patti Formation which is well represented at the centre of the southern Bida Basin in Nigeria. The major element composition of the studied shales and clays compare favourably with the reference shales, however, the trace elements vary slightly. Application of binary plot of TiO2 versus Al2O3 and Al2O3/TiO2 ratios of the studied shale samples show mixed mafic to felsic igneous sources. The chemical composition (plot of SiO2 versus Log (K2O/Na2O) indicates active to passive continental margin province, however, a minor derivation from recycled provenance is probable. Intense chemical weathering based on the high values of Chemical Index Alteration (CIA), Chemical Index of Weathering (CIW) and Zr values obtained from the shale and clay samples a warm humid condition is suggested. The high values also probably suggest predominance of clay minerals and low feldspar. This is supported by the XRD (X-Ray Diffractometer) data which indicates predominance of kaolinite in the samples.