Using an analytic hierarchy process-based index and geographic information system in geochemical exploration of gold

Abstract

In this study, a gold exploration index (GEI) that reduces financial expenditure and time losses during exploration studies has been developed using the analytical hierarchy process in a region where a high-sulfidation epithermal gold (Au) deposit exists. The GEI can be used to predict the location of the target element by evaluating the maps obtained from related element distributions together with a GEI-based prediction map. The hierarchical structure of the index has been established based on geochemistry of the rock samples. The elements used in the design of the hierarchical structure are arsenic (As), silver (Ag), antimony (Sb), copper (Cu), manganese (Mn), lead (Pb) and zinc (Zn), which are determined by the correlation analysis and experts’ opinions. The efficiency scores of the alternatives are converted into prediction maps called GEI-based anomaly distribution maps. These are compared with the maps derived from both geographic information system-based overlay analysis of the rock samples and spatial gold distribution. The efficiency scores of the alternatives in these maps are categorized into three groups as ‘high’, ‘medium’ and ‘weak’ in terms of gold potential. Comparison of the results with those derived using principal component analysis, weighted sum and weighted product models shows that the produced index yields reliable information that can be used to determine where gold enrichment occurs, especially in high-sulfidation epithermal environments.