HUANG Hui1, PAN Jia-Yong1*, ZHONG Fu-Jun1, YAN Jie2, HONG Bin-Yue3, KANG Qing-Qing4, WAN Jian-Jun1
(1. State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, China;
2. School of Earth Science, East China University of Technology, Nanchang 330013, China;
3. Fujian Institute of Geological Survey, Fuzhou 350013, China;
4. Team 224 of Sino Shaanxi Nuclear Industry Group, Xi’an 710024, China)
Abstract: The Huayangchuan U polymetallic deposit in the Xiaoqinling intracontinental orogenic belt, is a super-large polymetallic deposit, which dominated by uranium, niobium, and lead and associated "three rare" elements mineralization. In this paper, the LA-ICP-MS in-situ micro-area analytical technique is used to study chronology andtrace elements geochemistry of uraninite in the Huayangchuan U polymetallic deposit. The LA-ICP-MS U-Pb isotope age of uraninite is 133.2±0.96 Ma (MSWD=0.14, n=15), this indicates that there is a stage of uranium-niobium mineralization in the Cretaceous in the Huayangchuan U-polymetallic deposit. Uraninite gains have relatively low U/Th ratios and relatively high ∑REE contents, with obvious seagull type of chondrite-normalized REE patterns, but no negative Eu anomaly, indicating that the uraninitecould be formed in high temperature hydrothermal environment. Combined with mineralogical characteristics and regional magmatism, research suggests that regional magmatic activity around 133 Ma brings the mineralizers rich in water and fluorine components in the deep magma hydrothermal fluid to the shallow surface of the deposit, and the fluid migrates along with the regional fault structure. Ore-forming fluids altered the early pyrochlore and extracted and activated uranium from the edges and internal fissures.At the same time, uraninite, sphene, and pyrochlore altered by hydrothermal fluid in the later stage were formed.
Keywords: LA-ICP-MS; U-Pb dating; uraninite; U-polymetallic deposit; Huayangchuan
ACTA MINERALOGICA SINICA Vol. 40, No.5, 2020, page 569-583
