Mineral Resource Exploration Potential in the Ado-Ekiti-Ilesa Region of Southwest, Nigeria using Aeromagnetic Survey

Abstract

ABSTRACT This study investigates the mineral resource potential of the Ado-Ekiti and Ilesa regions in southwestern Nigeria using aeromagnetic data. These regions, located within the Precambrian Basement Complex and schist belts of Nigeria, are known for hosting significant mineral deposits, including gold, iron ore, and rare earth elements. However, limited geophysical exploration has constrained the full realization of their mineral potential. To address this, aeromagnetic data from sheets 243 (Ilesa) and 244 (Ado-Ekiti) were obtained from the Nigerian Geological Survey Agency and processed using advanced enhancement techniques to delineate geological structures and identify zones of mineralization. The study employed a suite of edge-detection filters, including Reduction to the Pole (RTP), Analytic Signal Amplitude (ASA), First Vertical Derivative (1VD), Tilt Derivative (TDR), and Total Horizontal Gradient (THG), to enhance the interpretation of magnetic anomalies. These filters improved the resolution of shallow and deep-seated features such as faults, shear zones, lithological boundaries, and dykes. Magnetic anomalies were classified into three litho-magnetic domains, corresponding to Older Granites and quartzites, undifferentiated metasediments, and mixed basement/metasedimentary sequences. Results reveal those high magnetic anomalies (65–251 nT) in areas like Ilesa and Osogbo are linked to magnetite-rich granitic and metamorphic rocks, indicative of iron ore and gold mineralization. Conversely, low anomalies (-12 to -174 nT) in regions such as Ifewara and Oriade correspond to quartzite and schist formations, potentially reflecting hydrothermal alteration zones or non-magnetic mineralization such as rare earth elements or hydrocarbons. Lineament analysis highlighted dominant NE–SW and N–S fault systems and NNW–SSE trending dykes, which are structurally significant for mineral deposition. The integration of aeromagnetic data with regional geological maps demonstrated a strong correlation between magnetic signatures and known lithological units. The methodology adopted allowed for the identification of both exposed and concealed mineral-bearing structures, providing a valuable tool for resource targeting....