SHU Tian-tian1, PAN Jia-yong1*, ZHONG Fu-jun1, QI Jia-ming2, HUANG Guang-wen1
(1. State Key Laboratory of Nuclear Resources and Environment, East China Institute of Technology, Nanchang 330013, China; 2. No.290 Institute, CNNC, Shaoguan 512026, China）
Abstract: Chloritization is one of the most important alteration types of hydrothermal uranium deposits in Southern China. Based on EPMA analysis and mineralogical study, chlorites in No.223 uranium deposit of Huangsha mining areain the middle of the Nanling Mountains are classified into 4 types. The chemical types of chlorite were divided; formation temperature and n(Mg)/n(Fe+Mg) value were calculated, and the formation mechanism and it’s relationship with uranium mineralization were discussed.The study found that the chlorites in No.223uranium deposit is divided into 4 types including biotite alteration type, feldspar alteration type, fissure filling type and uranium symbiotic type. They are mainly Fe-rich prochlorite formed under the reducing condition; the temperature range of formation of chlorite is 200－282 ℃, belonging to the mesothermal alteration, and the formation mechanism is composed of dissolution-crystallization and dissolution-migration-crystallization. It is clear that chloritization not only changes the physical mechaical properties and the occurrence state uranium in rock, but also provides the part uranium source of ore-forming fluid and a favorable geochemical environment for uranium mineralization.
Keywords: No.223 uranium deposit; chlorite; uranium mineralization; formation mechanism
ACTA MINERALOGICA SINICA Vol. 37, No. 6, 2017, Page 737-745