Delineation of Metallic Mineralization Zones using Integrated Aeromagnetic and Geochemical Data in the Basement Rocks of Oba-Akoko Area, Southwestern Nigeria

Abstract

The Oba Akoko area, southwestern Nigeria, lies within the Precambrian Basement Complex and is characterized by complex lithological units and Pan-African structural deformation. This study delineates metallic mineralization zones using integrated aeromagnetic and geochemical data. Fifteen (n = 15) geochemical samples were analyzed. Aeromagnetic data were processed to produce Total Magnetic Intensity (TMI), First Vertical Derivative (FVD), Euler deconvolution (structural index = 1), and lineament maps, with Euler depth solutions indicating shallow-to-moderate structural sources. Geochemical analysis involved ICP-MS following four-acid (HNO₃–HCl–HF–HClO₄) digestion with 0.45 µm filtration. Statistical evaluation used correlation analysis and Principal Component Analysis (PCA). Aeromagnetic results reveal dominant NE–SW to ENE–WSW structural trends interpreted as deep-seated faults and shear zones controlling crustal deformation and hydrothermal fluid migration. Magnetic highs correspond to mafic rocks, while lows indicate felsic or hydrothermally altered zones. Lineament and Euler analyses highlight structurally dense and highly prospective zones, particularly within the Ikun–Afo corridor. Geochemical results show significant enrichment in IKUN samples with Cu, Zn, Pb, Co, Ni, and Cr relative to background OBA values. PCA identifies hydrothermal (Cu–Zn–As–Pb–Co), lithological (Mo–Th), and mafic (Ni–Cr) associations, while correlation analysis confirms strong Cu–Zn–Pb relationships indicative of sulfide-related hydrothermal processes. Integration of both datasets reveals a strong structural control on geochemical anomalies, with consistent spatial coincidence between fault zones and elemental enrichment. The Ikun–Afo–Okeusi–Oka corridor is identified as the most prospective zone for metallic mineralization due to overlapping geophysical and geochemical signatures. This study confirms the effectiveness of integrated aeromagnetic and geochemical methods for mineral prospectivity mapping in Precambrian basement terrains.