REE DISTRIBUTION BETWEEN FLUORITE AND ORE-FORMING FLUID BASED ON RESULTS OF THERMODYNAMIC MODELING

Abstract

Being rather abundant, fluorite is widely used for the study of its REE patterns depending on the conditions of postmagmatic ore formation. It is very indicative that the turn of the century was marked by several publications in Russia and abroad devoted to discussion of the REE distribution in fluorites of rare-metal deposits from the viewpoint of possible physicochemical scenarios of its crystallization in the course of hydrothermal process. Despite the apparent diversity of chondrite-normalized patterns of REEs depending on their ordinal number, they are commonly distinguished by two main parameters: (1) the relative LREE and HREE concentrations and (2) the measured Eu content normalized to the half-sum of its nearest neighbors (Sm and Gd) designated as Eu/Eu*. The latter ratio is used as a formal estimate of the sign and rate of the anomalous behavior of Eu, because the denominator plays the role of the virtual (undistorted) Eu content.