Neotectonic Stage of the Formation of Rich Uranium Ores of the Khokhlovskoe Deposit in Jurassic Paleovalleys of the Eastern Ural Area

摘要

Brief information on specific peculiarities of the central part of the Khokhlovskoe deposit (structural, hydrogeochemical, mineralogical, and geochemical) is given in this paper. We consider in detail the methodology and results of estimation of the possible age of the formation of uranium-rich ores and the temperature hydrogeochemical anomaly in stratal waters determined by the methods of precise measurement of the radioactive equilibrium between ~(238)U and daughter products of its decay, as well as by analysis of a simplified model of heat transfer under such conditions. We obtained the same age estimations of violation of the uranium system in ores, <500 ka, which corresponds to the Late Quaternary age. According to the data of isotope ratios of ~(234)U and ~(230)Th (ionium), recent intense uranium introduction in rich ores and relatively lesser introduction in ordinary ores was established. With account for the specific peculiarities of the Khokhlovskoe deposit, the formation of rich uranium ores, as well as modern mineral and geochemical patterns of mineralization and altered rocks resulting mainly from exfiltration of thermal carbonic acid solutions into ore-hosting deposits at the late stage of neotectonic activization of the region, was substantiated.