Mineral Prospectivity Modeling over Julie Tenement of Northwestern Ghana using Geophysical Datasets

This study was set out to delineate prospective zones of gold mineralization occurrence over the Julie tenement of Northwestern Ghana using two spatial statistical techniques, namely information value (IV) and weight of evidence (WofE) models. First, ۱۱۰ locations, where gold (Au) mineralization has been observed, were identified by field survey results derived from highly anomalous geo-chemical assay datasets. Of these ۱۱۰ locations, ۷۷ (representing ۷۰% of the known locations, where gold has been observed) were randomly selected for training the aforementioned models, and the remaining ۳۳ (analogous to ۳۰% of the known Au occurrence) were used for validation. Secondly, eleven mineral conditioning factors (evidential layers) comprising analytic signal, reduction-to-equator (RTE), lineament density (LD), porphyry density, potassium concentration, thorium concentration, uranium concentration, potassium-thorium ratio, uranium-thorium ratio, geology, and arsenic concentration layers were sourced from geo-physical, geological, and geo-chemical datasets. Subsequently, by synthesizing these eleven evidential layers using the two spatial statistical techniques, two mineral prospectivity models were created in a geographic information system (GIS) environment. Finally, the mineral prospectivity models produced were validated using the area under the receiver operating characteristics curve (AUC). The results obtained showed that the IV model produced had a higher prediction accuracy in comparison with the mineral predictive model produced by the WofE with their AUC scores being ۰.۷۵۱ and ۰.۷۴۳, respectively.

Keywords:

Mineral prospectivity modeling , Information value , Weight of evidence , Aeromagnetic Data , airborne radiometric data