Best worst method-based mineral prospectivity modeling over the Central part of the Southern Kibi-Winneba Belt of Ghana

Abstract

The best–worst method (BWM), though a recently developed multi-criteria decision-making (MCDM) technique, has its application evolving in recent years in addressing MCDM problems. By employing the BWM technique, this study generated a mineral prospectivity map (MPM), primarily essential for the delineation of prospective regions of gold (Au) deposits over the central part of the Southern Kibi-Winneba belt. The MPM produced was generated by integrating seven geoscientific thematic layers derived from geophysical and geological datasets within the study area. These thematic layers were used as the main criteria for the generation of MPM, whose respective weights were determined based on the BWM technique by three decision-makers with in-depth knowledge of the use of geoscientific datasets for mineral exploration. The assigned weights obtained from the three decision-makers for each of the seven thematic layers were combined and normalised to obtain BWM weight for each evidential layer. These weighted evidential layers were subsequently integrated to produce the mineral prospectivity map over the study area. The mineral prospectivity map produced based on the BWM was evaluated based on known areas of reported Au occurrence and subsequently evaluated based on the frequency ratio technique to ascertain the coherence between locations of known mineral occurrence and the delineated prospectivity classes obtained. The performance of the prospectivity model produced was further assessed using the receiver operating characteristics (ROC) curve. An ROC score of 0.808 was obtained for the mineral prospectivity model (MPM) generated. The ROC score obtained indicates that the MPM produced exhibits a conscionable outcome for gold exploration over the central part of the southern Kibi-Winneba belt.