Estimating a favorability equation for the integration of geodata and selection of mineral exploration targets

Abstract

The notion of a favorability function for delineation of exploration targets has attracted attention among geologists and geomathematicians over the last decade, as indicated by the number of publications on this subject. Traditional estimation methods for a favorability equation carry several ambiguities in the meaning of the estimate. In order to avoid these problems, a special type of geological variable, referred to as the target variable appears in a favorability equation. Explanatory variables are usually physical and chemical descriptors of geologic objects, while target variables are usually available only in best explored regions. A favorability function should be defined as a linear combination of the explanatory variables, while the meaning of the function should be in terms of the target variables. Two objective methods, canonical correlation and weighted canonical correlation, are proposed in this paper. The estimation of a favorability equation by these methods is predicted upon a criterion that maximizes the correlation of the estimate of the favorability function and the target variables. Both methods are demonstrated on a case study of epithermal gold-silver vein deposits in the 2° Walker Lake quadrangle of Nevada and California. Targets for mineral exploration of gold-silver deposits were identified on the basis of the favorability functions by means of optimum discretization.