Malaysian Journal of Geosciences (MJG)

The distribution pattern of major elements’ mineralogy and geochemistry in the sandstones of the Lokoja Formation in the Southern Bida Basin of Nigeria was determined and used to classify and decipher the paleoclimatic conditions of the basin. X-ray diffraction (XRD) and X-ray fluorescence (XRF) were utilized to perform mineralogical and inorganic geochemistry investigations on seven (7) typical sandstone samples. Results of the mineralogical analysis, which showed clay matrix and feldspar content in high proportions, helped in interpreting the sandstone as texturally immature, belonging to the wacke clan and classified as feldspathic greywacke. Results of major element concentrations revealed that the sandstone has a depletion of MnO2 and P2O5 and an enrichment of SiO2, Al2O3, Fe2O3, CaO, MgO, and NazO. Geochemical classification plots, using log ratios of Na₂0/K2O against SiO2/Al2O3 and SiO2/Al2O3 against K2O/Na2O, also show that the sandstone is a greywacke. Similarly, the sandstone was categorised as sodic sandstones rich in plagioclase feldspars using a geochemical ternary diagram of potassium oxide (K2O) and sodium oxide (Na₂O) overlaid with fron oxide (Fe:D) and magnesia (MgO). The hivariate plot for chemical maturity indicated that the high 1 in 9e phots zrognas indies dry paleoclimatic state.