Identifying pathfinder elements from termite mound samples for gold exploration in regolith complex terrain of the Lawra belt, NW Ghana

Abstract

It is difficult to detect gold mineralization under cover of complex regolith comprising widespread ferruginous duricrust, extensive redistributed depositional and patchy residual materials of relict and erosional units by using gold (Au) analytical technique at Lawra belt. Commonly in these areas, the cover materials mask geochemical gold (Au) response to gold deposits under cover. Termite mound samples were collected from residually weathered materials. Fire assay (FA–AAS) was used to determine gold in the termiteria whereas the concentrations of the chalcophile and other selected elements were determined by XRF technique. The geochemical data were analyzed using bivariate and multivariate analysis to establish relationships among elements. Pearson correlation shows that Au, As, Zn, Mo and Cu have moderate to strong correlations. Factor analysis explained 91.53% of the total variance of the data through four factors. Factors 2 and 3 that constituted about 23% of the total variance of the data explained have elements associations with Au and that the elements in these factors are appropriate pathfinder elements. Spatial geochemical distribution of Au only detected small and erratic Au anomaly. Contrastingly the identified pathfinder elements using bivariate and multivariate analysis delineated broader anomalous areas that included gold (Au) anomaly detected by FA–AAS analytical technique. Hidden anomalies in the thick regolith overburden are detectable by the identified pathfinder elements. As and Zn were therefore identified as pathfinder elements suitable for defining Au mineralization in complex regolith environments.