Delineating and Interpreting the Gold (Mineralisation) veins within Bida and Zungeru sheets, Niger State Nigeria using Aeromagnetic and Radiometric Data

Abstract

Both Airborne Magnetic and Radiometric datasets were employed to interpret the geology and geological structures that serve as host to gold and associated minerals within the Bida and Zungeru, Niger State, Nigeria. An area of 55 by 110km 2, contained within the cretaceous sediments of Bida Basin and the meta- sediments of Zungeru-sarkin-pawa schist belt. Data interpretation involve the application of a mathematical algorithm for data enhancing such as, Reduce to the Equator, Analytical signal, First Vertical Derivative, and Centre for Exploration Targeting (CET) to the magnetic data, and Ternary imaging to the radiometric data, with a sole aim of mapping geological structures such as faults fracture folds joints and geological boundaries and possible gold mineralization veins that arise from hydrothermally altered zones. Two major geological units inhibit the study area, the cretaceous sediment, and the meta- sediments, major feature identifies within the Cretaceous sediment are the folds majority of which are located within the contacts. The result of the 1VD display is the vivid picture of the observed structural features such as faults fractures folds’ contacts labeled F1 to F8 both within the high region of magnetic susceptibility (in red) and low regions (in blue) geology contacts (yellow), folds (bold yellow) all across the field. Prominently at the North-Western corner of the study area are sets of linear structure that trend NE-SW, located within the contacts between the mylonites and the amphibolites and the belt-type meta- sediments located around Katakwo, Gindei, Kwange, Gabas and Akusu villages. Equallyworth mentioning are sets of lineament (in blue) trend E-W all across the mid-region of the study area, precisely at the Eastern corner within and below the Federal University of Technology Minna around Kata-eregi, Sabon- Dagan, Kakaki down Minkwoigi, Sunbwagi, Kakagi, Sabon dagga, and Bobo-shiri towns, where the majority of volcanic activities must have been recorded. The airborne radiometric show mobilization of the immobile thorium Th, concentration, and this also indicated hydrothermally altered zones. The increase in potassium concentration and decrease in K/Th relation observed from radiometric interpretation are very pinpointing of hydrothermal activities within the study area. The gold mineralisations are found within this vein and in the adjacent, highly deformed host rock located below the Federal University of Technology Minna Campus. The deformation seems to comprise principally of pebbly schist, amphibolites along fine-grained and magnetite