Aeroradiometric Data Assessment of Hydrothermal Alteration Zones in Parts of North Central Nigeria

Abstract

This work aims to map radioelement distribution, delineate hydrothermal alteration areas, and produce a surface geologic map of the area using recently acquired high-resolution aeroradiometric data covering parts of north-central Nigeria with estimated area coverage of 24, 200 Km2 . Radioelement maps, ratio maps, and composite radioelement maps were produced to accomplish this goal. The spatial distribution and occurrence of each radioelement were determined using the radioelement maps, and hydrothermal alteration zones that fell within the north, northeast, northwest, southwest, and eastern portions of the study area were delineated using the percentage potassium (% K)-equivalent Thorium (eTh) ratio (K/eTh) map. Some of these altered zones have one or more structural associations, implying that the structures serve as channels (pathways) for migrating hydrothermal fluids that reacted with rock formations that were later altered. The coincidences in these alteration zones with high lineaments densities areas discovered by previous work in this area suggest a high likelihood of the occurrence of prospective mineralization within these locations. The composite maps aided in the production of the studyarea's surface geology map, while the paleostructure trending NE-SE revealed in previous work within the study area based on aeromagnetic data analysis was delineated using both radioelement and composite radioelement (ternary) maps.