Gold Geospatial Interpolations: Kriging versus Inverse Distance Weighting

The E-W oriented Julie belt is located in the central portion of North-Western Ghana. The Julie gold deposit is currently the highest-grade in NW Ghana. It is located in the Wa-East gold district, which lies within the Julie belt south of the Koudougou-Tumu granitoid domain. The overall aim of this work is to highlight the role of Univariate Geostatistics in geospatial modelling, this would permit the prediction of the gold anomalous zones in the study area and delineate zones or specific areas where more resources can be invested. A total of 1088 soil samples were collected from the study area on grid bases using soil auger drilling, these samples were analyzed for gold only using Au fire assay at the SGS laboratory Australia and the multi element distribution was determined using xray fluorescence. To achieve the estimations, predictions and interpolations, Kriging and Inverse Distance Weighting (IDW) were employed after logarithmic transformation. The effectiveness of these methods in geospatial modelling using geochemical data was indicated. The histograms indicated a positively skewed distribution which suggest the other variables (As, W and Pb) as pathfinders for gold (Au). Models produced from both methods with the log. transformed data indicated about two anomalous zones, one being at the center of the study area, and another around the eastern arm of the area. Since the gold was hosted within extensively sheared zones of the granitoids, it is logical that gold is identified around the eastern part of the area because secondary dispersion mechanism must have consistently taken place to alter the primary constituent.