ON THE ORE PRODUCING POTENTIAL OF GRANITOIDS: EXPERIENCES IN THE U.S.S.R

Abstract

A wide variety of structural, petrochemical, geochemical and mineralogical indicators have been suggested as indicators for the identification of ore-producing granitoids. This paper is concerned only with those indicators which have been found to be of practical use in the U.S.S.R. These may be classed as: (1) geological and structural indicators; (2) petrological and geochemical indicators; and (3) mineralogical indicators. Useful quantitative characteristics include such features as: the average content of accessory minerals in the granite; the average content of the specific ore element in minerals bearing this element; the average accumulation ratio between the ore element in early and late differentiates; and the average value of the difference between ore-element concentrations in the granite and in its rock-forming and accessory minerals. Use of these quantitative characteristics can distinguish between productive and non-productive granitoids, as well as indicate some of the processes which may have controlled the formation of ore deposits.