Coupled spectral, geophysical, and topographic analysis for targeting tin-dominated polymetallic mineralization in the Kaiama–Shirigberia Basement Complex, Nigeria

The Kaiama–Shirigberia area of the Nigerian Basement Complex hosts cassiterite-bearing pegmatites and quartz veins associated with wolframite, tantalite, and minor copper mineralization. However, the complex structural and alteration controls on this tin-dominant polymetallic system and the limited integration of surface and subsurface datasets have constrained systematic assessment of its mineral potential. This study develops a multi-scale, process-based framework integrating field geological observations, structural analysis, Sentinel-2 multispectral imagery, digital elevation model (DEM)-based lineament analysis, and high-resolution aeromagnetic and radiometric datasets. Structural features were characterized using field measurements and DEM-based lineament analysis, while aeromagnetic data were processed using reduction-to-the-pole and first vertical derivative techniques to enhance lithological and structural contrasts. Radiometric potassium (K), thorium (Th), and uranium data were used to derive the K/Th ratio as an indicator of hydrothermal alteration and potassic enrichment. These datasets were integrated to develop a Tin Favorability Index (TFI), which was subsequently combined with Sentinel-2-derived spectral alteration indicators to generate an Integrated Mineral Potential Index (IMPI). Validation against 30 known tin occurrences shows that 86.66% fall within moderate to very high IMPI potential classes, including 33.33% within the very high class. The results indicate that mineralization is associated with NE–SW, N–S, and NW–SE structural corridors, elevated K/Th ratios, subdued magnetic responses, and surface alteration signatures, reflecting the combined influence of structural permeability and hydrothermal processes. The study provides a transparent, multi-scale framework linking field-scale geological evidence with regional geophysical and satellite-derived indicators for tin-dominant polymetallic prospectivity assessment and exploration targeting.