Geology and Copper Ore Mineralization in the Mozambique Belt Rocks of the Kwa Vonza–Mutonga Area, Kitui West, Kenya
Abstract
The study area in western Kitui County, southeastern Kenya, is underlain by Neoproterozoic rocks of the Mozambique Belt, characterized by metamorphism, deformation, granitoid intrusions and mineralization. Despite its mineral potential, detailed studies of copper mineralization in the Kwa-Vonza–Mutonga area remain limited. This study investigated the geology and copper mineralization, focusing on host lithologies, structural controls and copper enrichment. An integrated approach involving Sentinel-2 Level-2A remote sensing, geological field mapping, petrography, X-ray fluorescence (XRF) and X-ray diffraction (XRD) was applied. Sentinel-2 imagery was processed in ArcGIS 10.8 using false-colour composites, spectral band ratios and image enhancement techniques to support lithological discrimination and identify alteration zones and structural lineaments. Enhanced imagery, band-ratio maps, alteration maps and lineament information were integrated with field observations to improve geological interpretation and delineation of mineralized zones. Lithological units were established primarily through field mapping based on mineralogical, textural and structural characteristics and validated using petrographic analysis, with remote sensing providing complementary spatial information. The study established that the area comprises granitoid gneisses, banded biotite gneisses, migmatites, meta-mafic and meta-felsic rocks, granitic and schistose gneiss, granulite and surficial deposits. Copper mineralization is predominantly associated with mafic and felsic rocks, particularly metagabbro and metagranite, and is concentrated along deformed contacts between mafic and felsic units, faults, fractures, joints, foliation planes and vugs. Remote sensing identified lineaments and alteration-related anomalies coinciding with mapped mineralized zones and artisanal workings, while geochemical results confirmed copper enrichment in altered and structurally controlled lithologies. A preliminary assessment indicates approximately 466 tonnes of contained copper within the mineralized zone. This estimate is based on geological observations from one trench, measured dimensions, bulk-density determination and available geochemical data and should not be regarded as a formal Mineral Resource for the whole study area. Drilling and subsurface investigations are required for resource validation.