RESEARCH PROGRESS AND PROSPECTING DIRECTION OF URANIUM MINER-ALIZATION IN PRE-SINIAN MIGMATITE IN KANGDIAN AXIS AREA
In recent years,the discovery of coarse-grained and ultra-rich uranium ore types in the Pre-Sin-ian migmatite area of the central and southern Kangdian Axis has garnered significant attention due to their rarity and high scientific value.Building on previous research,our team systematically analyzed the char-acteristics and mineralization processes of these ultra-rich uranium ore deposits,identified key scientific problems,and discussed future research and prospecting directions.We identified two types of uranium deposits in the migmatite of the Kangdian Axis,resulting from two distinct stages of uranium mineraliza-tion.The initial stage involved typical magmatic mineralization,characterized by a uranium-titanium-phos-phorus element combination.In this stage,crystalline uraninite is closely associated with minerals such as ilmenite,phosphoyttriite,monazite,rutile,zircon,thorite,cubic thorite,fluorapatite,and sphene,with a notable absence of sulfides.The later stage is related to hydrothermal mineralization that occurred post-magmatic activity.This stage features a typical ore-forming element combination of uranium,molybde-num,copper,and sulfur,with crystalline uraninite closely associated with pyrite,pyrrhotite,and molyb-denite.The age of uranium metallogenesis in the region is primarily concentrated between 760 and 1000 million years ago,corresponding to the Neoproterozoic era,during the transition from compressional orog-eny to extensional tectonics.The differentiation of silicon,phosphorus,and fluorine-rich fluids during the late stages of alkaline magmatic evolution is crucial for the formation of coarse-grained crystalline uranium deposits.Additionally,the coupling effects of deep melting processes and extensive ductile shear zones play a significant role in controlling uranium mineralization.Our findings suggest that the initial stage of uranium enrichment and low-grade mineralization was facilitated by deep magma penetration related to ductile shearing,leading to the formation of migmatite.In the subsequent stage,structural-fluid interac-tions resulted in the formation of very high-grade uranium ore.Post-mineralization,tectonic activities and crustal uplift significantly altered and damaged the ore bodies.In conclusion,comprehensive analysis indi-cates that the Kangdian Axis has experienced geological events and mineralization processes conducive to high-intensity uranium mineralization.The migmatite in this region holds significant potential for the re-connaissance of ultra-rich uranium deposits,warranting further exploration and research.
Ultra-rich uranium depositCoarse-grained uraniniteMineralizationPresinian-periodKang-dian area
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