Geological and Geochemical Characterization of Kyanite-Bearing Rocks Around Kuta Part of Minna Sheet 164, North Central Nigeria

The study investigates the geological and geochemical characterization of rocks in an area of about 21 km2 in vicinity of Kuta North Central Nigeria with a view to identify the relationship between the rock units, the petrographic characteristics of the rock assemblages, their original protoliths, and geochemical characterization of the rocks. Field and laboratory works such as: petrography, X-ray Fluorescence (XRF), and X-ray Diffractometer (XRD) have revealed that the study area is entirely underlain by metasedimentary Precambrian pelitic rocks characterized mostly by mica schist, quartzite ridge complex (in NE-SW direction), quartz-kyanite schist, and Banded Iron Formation (BIF). The discrimination diagrams constructed reveal the following: greywacke, tholeiitic, and arc related origin of the mica schist; tholeiitic with meta-arkosic nature of the quartzite; the hybrid sedimentary-igneous protolith (greywacke and arkosic) nature of the quartz-kyanite schist; and the terrigenous and submarine hydrothermal for the BIF. The petrographic and XRD study indicate that the mica schist consist of quartz, phlogopite, paragonite, muscovite, kyanite, topaz, rutile, kaolinite, and magnetite assemblages and quartzite consist mostly quartz, topaz, kyanite, and rutile. The quartz-kyanite schist consist quartz, kyanite, muscovite, topaz, paragonite, kaolinite, rutile, and hematite, while and the BIF composed of magnetite, quartz, hematite, and rutile.

The mean percentage of the major defining chemical elements (such as alumina and silica) for kyanite mineralization potential rocks according to standard requirements of kyanite for industrial use, indicates that the rocks contain a very low amount of alumina with higher percentage values of deleterious elements such as SiO2, Fe2O3, TiO2, Na2O+KO2 and MgO+CaO. The mineralogical analysis (via XRD) and modal analysis during petrographic studies show that the percentage composition of kyanite in the kyanite bearing rocks is greatly below the acceptable limit when compare to other economic kyanite deposits around the world.