Mesothermal gold prospectivity mapping of the southern Kibi-Winneba belt of Ghana based on Fuzzy analytical hierarchy process, concentration-area (C-A) fractal model and prediction-area (P-A) plot

Abstract

In this paper, the southern Kibi-Winneba belt, which shares geological resemblance with the renowned Ashanti belt in Ghana has been investigated to delineate prospective zones of gold mineralization occurrences. The generation of a mineral prospectivity map (MPM) for the study area comprised the integration of nine (9) exploration layers obtained from geological, remote sensing and geophysical datasets based on the Fuzzy analytical hierarchy process (FAHP) approach and geographical information systems (GIS). The employability of the FAHP in the assignment of weight to the nine (9) evidential layers based on their comparative importance with respect to the mineral being sought (which is gold in this study) was carried out by experts in remote sensing and geophysical techniques for mineral exploration. The weights of the evidential layers were subsequently normalized and integrated to produce an MPM of gold deposits within the study area based on a fuzzy operator of γ = 0.9 in GIS. For an elaborate evaluation of the MPM, the concentration-area (C-A) fractal model was employed to classify the generated MPM to obtain 6 thresholds for the generation of a final MPM for the study area. Further evaluation of the MPM was carried out by the prediction-area (P-A) plot based on 15 locations of known gold occurrences, with results obtained predicting that 25% of the study area as prospective regions of gold deposits, within which 75% of the known gold occurrences have been delineated.