MINERALOGICAL AND GEOCHEMICAL CHARACTERISTICS OF THE HURIVKA COMPLEX P-U-TR ORE OCCURRENCE, INHUL MEGABLOCK, UKRAINIAN SHIELD

Abstract

The article presents the results of the study of the Hurivka apatite-uranium-rare earth ore occurrence, which is confined to the contact of the southern part of the Hurivka granitoid massif with metasedimentary rocks of the Inhul-Inhulets series. Argillizites, which host the productive mineralization, are represented by two zones: the lower montmorillonite-chlorite zone and the upper kaolinite-chlorite zone with hydromica. The concentrator minerals of rare earths (∑TR=0.05-0.5 %) in the bedrock are xenotime and monazite, while only xenotime was detected in argillizites. At the same time, minor impurities of yttrium and lanthanides were detected in apatite, chlorite and clay minerals. Xenotime and monazite also contain insignificant concentrations of uranium. The maximum uranium content in xenotime is 4.94% UO2, and in argillizites it can reach 0.86%. No native uranium minerals were detected in the studied ore. It is assumed that the most common form of its occurrence in argillizites is adhesion to the surface of clay and mica minerals due to sorption and adsorption processes. Anomalous high phosphorus content within the ore occurrence is associated with apatite mineralization. In bedrock, apatite is confined to skarns. In argillizites, its concentration in some intervals reaches 5%. The complex apatite-uranium-rare earth mineralization of the Hurivka ore deposit was formed in the course of complex long-term processes, which was expressed in the hydrothermal-metasomatic transformation of high carbonated rocks in contact with the granitoid massif and their subsequent argillization by low-temperature hydrotherms of endogenous and exogenous origin.