SEDIMENTOLOGY AND DETERMINATION OF HYDRAULIC CONDUCTIVITY OF OUTCROPPING SANDSTONE FACIES OF PATTI FORMATION EXPOSED AT KOTON-KARFE, SOUTHERN BIDA BASIN, NIGERIA

The sedimentological studies and hydraulic conductivity determination of sandstone facies of Patti Formation exposed at Koton-karfe, Southern Bida Basin Nigeria has been carried out. This research is aimed at investigating the sedimentological and hydraulic conductivity attributes of outcropping sandstone sediments in the study area. The methods employed include sieve analysis, petrographic analysis and permeability tests. The granulometric analysis showed that the sandstone sediments are medium to coarse grained. This is believed to have resulted from medium to high energy of deposition. The result also showed moderately well sorted to poorly sorted sediments. Indicating different porosity attributes. Good sorting implies good porosity while poor sorting implies poor porosity. The moderately well sorted and moderately sorted sediments have grains of fairly the same size and are evidence of sediments transported far from source while poorly sorted sediments are vice-versa. Also, the petrographic analysis revealed quartz, feldspar, biotite, tourmaline and zircon as the major mineral constituents in the analyzed sandstone sediments with the proportion of quartz being the highest. The occurrence of monocrystalline quartz in the thin-section indicates that the sediments were derived from volcanic-plutonic basement rocks. They also have a large contribution from metamorphic rocks because of the presence of heavy minerals like tourmaline and zircon. The minerals have different shapes like angular, subangular, rounded and subrounded. This implies that some of the sandstone sediments are deposited close to the source and others far away. The estimated K values of 1.92 × 10−5 and 1.48 × 10−5 m/s were obtained for the selected soil samples. This indicates that the sediments are poorly permeable. Poor permeability lowers the ability of a rock to transmit fluid efficiently. The economic deposits such as laterites and sandstone are of utmost importance to the local community and country a whole.