Integrated Aeromagnetic and Radiometric Investigation of Structural Controls on Pb-Zn Mineralization in the Ohinya Area, Abakaliki Basin, South-eastern Nigeria

Abstract

This study assesses the lead-zinc (Pb–Zn) mineralization potential of the Ohinya license area in the Abakaliki Basin, southeastern Nigeria, through integrated interpretation of aeromagnetic and radiometric datasets. The primary objective is to delineate prospective structural and lithological zones that may host hydrothermal Pb–Zn mineralization and to establish a geophysical framework to guide further exploration. High-resolution airborne geophysical data, including Total Magnetic Intensity (TMI), First and Second Vertical Derivatives (1VD and 2VD), analytic signal, tilt derivative, Source Parameter Imaging (SPI), and radiometric data (K–Th–U) were processed and interpreted to define subsurface structures and estimate depths to magnetic sources. The results reveal that NE–SW and NW–SE trending faults predominate, with SPI depths ranging from 270 to 330 m. The central and southeastern zones, marked by high analytic signal amplitudes (0.006–0.008 nT) and Th–U enrichment, are interpreted as structurally controlled hydrothermal corridors prospective for Pb–Zn mineralization. The study, however, is subject to limitations inherent in airborne geophysical methods, such as the resolution of aeromagnetic data, approximate depth estimates from SPI, lack of ground validation, and the restriction of radiometric data to near-surface signatures, which may be affected by weathering and surface cover. Despite these constraints, the integrated approach offers a robust framework for reducing exploration uncertainty. The identified prospective zones merit follow-up investigations, including geological mapping, geochemical sampling, trenching, ground geophysical surveys, and ultimately drilling to confirm the presence and economic viability of Pb–Zn mineralization.