Geology and economic mineralization of the neoproterozoic Mozambique belt rocks of the Mwitika-Makongo area, Kitui County, South Eastern Kenya

The Mwitika-Makongo research area occurs within the Neoproterozoic Mozambique metamorphic belt in Kenya and is located in Kitui East sub-county of Kitui County. The area is bounded by longitudes 38° 18'E and 38° 26'E and latitudes 1° 22'S and 1° 32'S. This area is easily accessed from the Nairobi-Thika-Kitui-Zombe road or the Nairobi –Machakos-Kitui-Zombe road. From previous geological works, it had been established that several mineral resources of economic potential like iron ore, magnesite, and various gemstones were present in the area. However, despite this possible mineral richness, an enigmatic problem exists where their occurrence, genesis and related mineralization are not satisfactorily understood including their economic potential. To address the aforementioned problem, this study integrated geological, geochemical and remote sensing investigations to establish economic mineralization in the area. The first objectives of this study were to identify lithological units and geological structures related to potential economic minerals. The other objectives were to establish economic minerals formation history and their probable quantity in the study area. Geological methods consisted of, field mapping and geochemical analysis. The remote sensing methods included; band combinations, principal component analysis and lineament extraction. Investigations using remotely sensed data established widespread previously undocumented geological structures, new lithological units and undiscovered mineral alteration zones. Through this study, it was established that the project area lies within a medium to a high-grade metamorphic zone of the Neoproterozoic Mozambique belt. Structurally, the rocks of the project area have a NE trend with westerly or easterly dips. This study identified that the intrusives rock units in the project area were associated with economic mineralization of iron ore, magnesite and heavy mineral sands. Geochemical and petrographic evidence ascertained that the study area is rich in mineral resources that can boost its economic status. For example, the iron ore in Kalima Kathei area contained above 86% Fe2O3 which corresponds to acceptable levels of commercial iron ores. From an economic geological point of view, the area has the potential to produce economic rocks like marbles and ornamental rocks, economic minerals like iron ore, Magnesite and heavy mineral sands with traces of titanium. Surface estimation of the resources in the Mwitika-Makongo area was as follows; Marble at 22, 748 tons, iron ore at 172.5 tons and Magnesite at 620 tons. This study, therefore, recommends exploitation of these resources, to bring great economic growth in Kitui County as a whole. This study recommends drilling works to establish the actual tonnage and quality of the established deposits.