Mineral exploration or resources appraisal commonly employ geoscience concepts and available geoscience information to delineate subareas of special interest, such as geochemical and geophysical anomalies, exploration targets, metallogenic units, and favorable resource areas. These subareas may be thought of as being homogeneous with regard to the information and concepts used to delineate them and are here referred to as consistent geologic areas. The further subdivision of these areas into drilling targets or study areas based upon additional geoscience information is a task with which some geologists must deal. This paper develops an objective, quantitative methodology for further subdividing consistent geologic areas by the delineation of geologic heterogeneities. This methodology employs the principle of relative exceptionalness to identify locations that exhibit exceptional variation in normalized scores of geologic factors. The methodology is demonstrated on the Walker Lake quadrangle of Nevada and California, an area which contains epithermal gold-silver deposits.