Unconstrained 3D Inversion of Airborne Magnetic Data for Mineral Targeting in the Southwestern Nigerian Basement Complex

This study applies unconstrained 3D inversion of high-resolution airborne magnetic data to model subsurface susceptibility distribution in the Southwestern Basement Complex of Nigeria. Total magnetic intensity (TMI) data were processed to residual magnetic anomalies, first vertical derivative (FVD), and analytical signal maps, followed by inversion using GM-SYS 3D in Oasis Montaj software (cell size: 250 × 250 × 100 m). The model converged after 50 iterations, achieving an RMS misfit of and . High-susceptibility anomalies (>0.05 cgs) extend laterally over 5–20 km and to depths exceeding 1.5 km, aligning with major NE–SW and NW–SE structural corridors. Integration of magnetic depth estimates, structural trends, and inversion results highlights prospective targets for iron oxide–copper–gold (IOCG), skarn-type, and gold-bearing systems. These targets coincide with structurally complex zones near the boundaries of high and low magnetic domains. The results provide a framework for prioritizing mineral exploration in the region.