Application of Electromagnetic and Gravity Methods in Uranium Exploration Within the Basement Complex of Northern Enugu

The basement complex rocks exposed in portions of northern Enugu State have shown geochemical anomalies suggesting potential radioactive mineral enrichment, warranting a systematic geophysical investigation for uranium prospectivity. This study applies electromagnetic profiling and Bouguer gravity analysis to investigate uranium exploration targets within the basement complex of northern Enugu. EM34 horizontal coplanar and vertical coplanar mode data were collected at 40 m station spacing along eight traverses targeting known radioactive anomaly areas. Gravity measurements were acquired at 500 m station spacing across a 180 square kilometre survey area, and Bouguer anomaly maps were produced after standard corrections. The EM34 data reveal pronounced conductivity highs associated with graphitic schists and altered gneisses, rock types that commonly host uranium mineralisation in granitic terrain. Gravity anomaly highs in the northern sector are correlated with mafic intrusions within the basement, while negative gravity anomalies indicate granitic plutons, which are the preferred host rocks for uranium mineralisation. Spectral analysis of the Bouguer anomaly data estimates depths to major density interfaces ranging from 1.5 to 6.5 km. Qualitative integration of the two datasets delineates four anomaly zones where electromagnetic conductivity lows spatially coincide with gravity negative anomalies, suggesting uranium-enriched granitic bodies. Gamma-ray spectrometry data collected along key profile intersections confirm elevated uranium equivalent concentrations. These priority zones are recommended for detailed follow-up investigation and radiometric drilling.

Keywords: electromagnetic profiling, Bouguer gravity, uranium exploration, basement complex, radioactive mineralisation