赣南6722铀矿床钛铀矿-晶质铀矿-铀石-沥青铀矿显微共生组合的厘定及成因意义

New Finding of Brannerite—Uraninite—Coffinite—Pitchblende Micro-assemblage and Its Genetic Significance at the No. 6722 Uranium Deposit,Southern Jiangxie Province

通过235U诱发裂变径迹及电子探针测试综合研究,在6722铀矿床的含矿隐爆角砾岩胶结物中首次发现钛铀矿—品质铀矿—铀石—沥青铀矿显微共生组合.这样一种在1 cm2（光薄片）范围内分布,而且不存在任何脉状相互穿插现象的钛铀矿—晶质铀矿—铀石—沥青铀矿显微共生组合表明其形成于同—成矿物理化学体系中.根据UO2—TiO2 —H2O体系稳定场,确定6722铀矿床中钛铀矿—晶质铀矿—铀石—沥青铀矿显微共生组合形成温度范围为250～350℃,属中—高温热液成因.

Using the 235U induced fission-track method and microscopic annalysis,the brannerite —uraninite —coffinite —pitchblende micro-assemblage in ore-bearing cryptoexplosive breccia from No 6722 uranium deposit is firstly determined.This mineral micro-assemblage distributing in a micro-limited area （1cm2,polished thin section） were formed from a physic-chemical system.According to the stability fields of uranium minerals synthesized in the UO2—TiO2—H2O system,it is confirmed that the brannerite—urannerite —coffinite—pitchblende micro-assemblage of No 6722 uranium deposit was formed within the range of 250 ～ 350℃ and attributed to middle—high hydrothermal genesis.