METHOD OF IDENTIFYING PLACER HALOES BY MORPHOMETRIC STUDY OF GOLD GRAINS

Abstract

Current techniques for identifying placer haloes of gold are not always effective. We propose to study placer gold (as well as the metal extracted from ground material) by determining the principal morphometric characters of each grain, i.e., its length, its width, and its thickness, followed by calculation of its 'shape coefficients.' Based on the morphogenic systematics of native gold segregations, we subdivide the grains into types, species, and varieties in terms of the shape coefficients. In diagnosis of the grains we describe (and, where possible, evaluate quantitatively) such other properties as color (a direct indicator of the assay), degree of rounding (on a 6-point scale), surface relief, presence of supergene films, face impressions, and intergrowth with other materials. Statistical processing of the data gives, for each observation point (in plan and in section), information that can be used for area charting of clastic gold and for local forecasting of its occurrence.