A preliminary geophysical investigation of lead mineralization in parts of the crystalline basement complex of Nigeria

The present study investigated crustal structures and geological bodies in parts of the crystalline basement of Nigeria using high-resolution airborne magnetic data and a Very Low-Frequency Electromagnetic survey. The purpose is to provide preliminary insight into the lead mineralization identified for the first time in parts of the crystalline basement, as well as to find new promising areas for follow-up mineral investigations. Aeromagnetic anomaly data were interpreted across the study area using standard geophysical techniques consisting of horizontal gradient magnitude, pseudo-gravity transformation and source parameter imaging. The horizontal gradient magnitude anomalies reveal a considerable component of the studied area hosting the lead mineralization. The pseudo-gravity transformation identified a few northwest-southeast geological features which are characterized by high pseudo-gravity anomalies and surrounded on both sides by linear low anomalies that signify a structural deformation. The source parameter imaging shows more closely the geological formation hosting a known lead mining site. To precisely map the extension and trend of the lead mineralization within the geological formation, five very low-frequency electromagnetic survey profiles were established in a northeast-southwest direction covering parts of the geological formation. The results showed northeast and north-northeast extensions of the lead mineralization within the geological formation. Our overall assessment demonstrates the integration of magnetic and Very Low-Frequency Electromagnetic methods as powerful tools for mapping lead deposits.