Radiometric and geochemical indicators in anthills as guides for mineral exploration in Bashar Upper Benue Trough North Central Nigeria

Abstract

This study evaluates the potential of anthill radiometric and geochemical signatures as indicators for preliminary mineral exploration in the Bashar area of the Upper Benue Trough, north-central Nigeria. The objective was to assess the distribution of uranium (U), thorium (Th), and potassium (K) in anthill materials and evaluate their geological and exploration significance. A total of 234 field radiometric measurements were acquired using a portable gamma-ray spectrometer, while 10 representative anthill samples were analyzed for elemental composition using X-ray fluorescence (XRF). Elemental concentrations, including U, Th, and K, together with Th/U and Th/K ratios, were evaluated to support geological interpretation. Results show mean concentrations of 4.18 ppm U, 13.75 ppm Th, and 9,800 ppm (0.98%) K in the anthill materials. Elevated Th/U ratios in parts of Jarmai, Bashar, Zurak, and Sabon-Gari may indicate relative thorium enrichment and the possible presence of thorium-bearing accessory minerals. Geochemical relationships, including Fe–Ti and K–Rb associations, suggest contributions from oxide minerals and felsic source materials, respectively. Radiometric anomalies show spatial correspondence with lithological and structural variations across the study area. Overall, the results indicate that anthill materials preserve measurable radiometric and geochemical signatures that may provide useful preliminary information for mineral exploration. However, in the absence of direct paired comparisons with adjacent soils and underlying bedrock, anthills should be regarded as a potentially useful reconnaissance sampling medium rather than a fully validated exploration tool. Further systematic paired sampling is recommended to establish their reliability and broader applicability in mineral exploration.