Hydrothermal alteration and mineral potential zones of Bauchi area Northeastern Nigeria using interpretation of aeroradiometric data

Abstract

This research focuses on hydrothermal alteration and mineral potential zones of the Bauchi area in northeastern Nigeria using the interpretation of aeroradiometric data. The high resolution aeroradiometric data were acquired and analyzed for possible areas of mineral potentials, lithologic units, and hydrothermal alteration. The radiometric data were interpreted by minimum curvature gridding techniques, arranged in three different grids as radioelement of percentage potassium (%K), equivalent thorium (eTh), and equivalent uranium (eU), and were displayed as pseudo[1]coloured images to reveal the surface concentration of each of the radioelements. The radioelement maps, K/eTh ratio map, and ternary image were used to recognize and interpret the radiometric signatures for mineral potential zones, lithological units, and identification of hydrothermal alteration zones in the study area. The relatively high eTh concentration (32.1274-54.8017 ppm) could be attributed to granitic rocks and high K/eTh ratio (0.285718-0.422418 wt%/ppm) indicates hydrothermally altered areas. The regions with high %K, high eTh and high eU coincide with the granitic rocks and this indicates that hydrothermal alteration and mineral potential zones are predominance in older granites and younger granites. The hydrothermal alteration zones are favorable areas for mineralization as observed from the K/eTh ratio map. The hydrothermally altered areas are underlain by granitic rocks and this attests that the hydrothermal alteration process is accompanied by granitic intrusions and emplacement of late intrusive rocks which provide the heat sources for hydrothermal solutions along fractures for the formation of minerals or react with the enclosing rock for hydrothermal alteration and subsequent mineralization.