Integrated Airborne Magnetic and Gamma-Ray Spectrometric Analysis for Mineral Prospectivity in Pategi, North Central Nigeria

Abstract

Mineralisation assessment within southern parts of Bida basin was carried out employing the analyses of airborne magnetic and radiometric data set. The concept of harmonising geological structures and hydrothermal alterations as dual evidence of inferred mineralisation was put together via detailed data enhancement, qualitative and quantitative interpretations. The total magnetic intensity map (TMI) revealed the distribution of magnetic signatures across the study area. First vertical derivative (FVD), Analytic Signal (AS) and CET analyses were used to delineate underlying geologic structures associated with ore deposits. Main structures inferred as faults, fractures and contacts were mapped trending in the NE – SW directions. Anomalous concentrations of radioactive elements (K, eTh and eU) up to 4.60 %, 54.29 ppm and 10.90 ppm, exceeding crustal average of 2.5 %, 12.0 ppm and 3.0 ppm respectively were mapped across study regions. The variation of eTh and eU against potassium as a trade-off for potassium enrichment was used to delineate regions of hydrothermal alterations.  Potassium_thorium ratio (K/eTh), Potassium deviation (K_D) and F_parameter were analysed and interpreted collectively with their high occurrences indicating rock alterations. The regions of hydrothermal alterations corresponding to outlined major structures were designated as zones of potential mineralisation. The mapped areas include: Bankole, Aiyetoro, Babanla, Ndeji on the NW regions, below Ekati, Matokun and danikun, Esanlu-Esa at the central regions and the southern regions includes Omugo, Okunran, Egbe, Eruku, Isanlu, IJagbe, Mopa, and Ogbe. The regions of interest could be focused on using concise ground geophysical methods to ascertain the implied prospect.