投稿时间：2020-05-06
修订日期：2020-10-31
网络发布日期：2021-01-08
中文摘要:邹家山矿床位于赣杭构造火山岩铀成矿带与大王山-于山花岗岩型铀成矿带的复合叠加部位。矿体产于下白垩统鹅湖岭组上段碎斑熔岩和打鼓顶组上段流纹英安岩中，呈脉状、细脉状，主要受NE向邹家山-石洞断裂带控制。围岩蚀变主要为萤石化、伊利石化、黄铁矿化、绿泥石化、碳酸盐化等。文章通过野外地质调查、地球化学分析、电子探针分析及矿物自动定量分析等方法，对该矿床超常富集铀矿石中Ti的赋存特征展开研究，结果表明，超常富集铀矿石中w（TiO2）和w（U）特征与前人研究的w（TiO2）和w（U）呈非线性正相关的结果不同。超常富集铀矿石中平均w（TiO2）仅是围岩的1.90倍，而平均w（U）却是围岩的565倍，TiO2与U相比富集程度并不高。元素相关性研究发现超常富集铀矿石中w（TiO2）与w（U）呈中度负相关，与易形成络阴离子的F、S、P2O5含量关系不明显，而w（U）与F、S、P2O5含量呈正相关，说明成矿环境中U与Ti物理化学性质差别较大，物质来源可能不同。超常富集铀矿石中Ti主要赋存于钛铀矿中。钛铀矿呈自形-半自形，大小约1~75 μm，大量分布于白云石、铁白云石等边缘。钛铀矿既包裹着早期的沥青铀矿，又被晚期的沥青铀矿包裹。经研究分析认为，铀矿石中Ti主要来源于赋矿围岩中的黑云母蚀变，胶体TiO2矿物对U的强吸附性有利于钛铀矿的形成，并促使U在地球化学障处超常富集。但铀成矿后期，热液中Ti几乎耗尽，钛铀矿不再新增，伴随成矿环境的改变，部分钛铀矿缓慢溶蚀以及被新形成的沥青铀矿交代，引起Ti流失，导致超常富集铀矿石中w（U）与w（TiO2）为中度负相关。
Abstract:The Zoujiashan deposit is located in the composite superimposition of the Ganhang structural volcanic rock uranium metallogenic belt and the Dawangshan-Yushan granite type uranium metallogenic belt. The orebodies occur in the porphyry lava of the Upper Ehuling Formation and rhyolite dacite of the Upper Daguding Formation of the Lower Cretaceous. The wall rock alterations include mainly fluoritization, illitization, pyritization, chloritization and carbonation. By means of field geological survey, geochemical analysis, electron microprobe analysis and mineral liberation analyser, the authors studied modes of occurrence of titanium in the ore. The results show that the content characteristics of TiO2 and U in the supernormal enriched uranium ore are different from those of the previous studies, which argue for the nonlinear positive correlation between the content of TiO2 and U. The average content of TiO2 in the ore is only 1.90 times that in the surrounding rock, while the average content of U is 565 times that in the surrounding rock. Compared with U, the enrichment of TiO2 is not high. The element correlation study shows that the content of TiO2 and U in the ore shows moderately negative correlation. The relationship between the content of TiO2 and the content of F, S and P2O5 which is easy to form complex anion is not obvious, but the content of U is positively correlated with the content of F, S and P2O5. These data indicate that the physicochemical properties of U and Ti are quite different in metallogenic environment, and the material sources may be different. Ti mainly occurs in brannerite. The brannerite is euhedral and subhedral, with a size of 1~75 μm. It is widely distributed at the edge of dolomite and ankerite. Brannerite is wrapped not only by the early uraninite but also by the late uraninite. It is considered that Ti of uranium ore is mainly derived from biotite alteration in host rock. The strong adsorption of uranium by colloidal TiO2 minerals is beneficial to the formation of uraninite and promotes the supernormal enrichment of uranium at geochemical barrier. However, brannerite would not increase because Ti of hydrothermal solution is almost exhausted at the late stage of uranium minera-lization. With the change of metallogenic environment, some brannerite is slowly dissolved and replaced by newly formed uraninite, which leads to the loss of Ti, resulting in moderate negative correlation between w(U) and w(TiO2) in supernormal enriched uranium ore.
keywords:geochemistry supernormal enrichment brannerite occurrence form of Ti uranium metallization Zoujiashan deposit
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基金项目:本文得到国家自然科学基金项目（编号：41472069、41572185），中国地质调查局地质调查项目（编号：DD20190128）和东华理工大学博士启动基金（编号：DHBK2019051）联合资助
引用文本：
王运,胡宝群,高海东,邱林飞,孙占学,郭福生,周万蓬,吴志春.2020.邹家山矿床超常富集铀矿石Ti的赋存特征及其铀成矿意义[J].矿床地质,39(6):1049~1062WANG Yun,HU BaoQun,GAO HaiDong,QIU LinFei,SUN ZhanXue,GUO FuSheng,ZHOU WanPeng,WU ZhiChun.2020.Modes of occurrence of Ti in supernormal enriched uranium ore of Zoujiashan deposit and its significance for uranium mineralization[J].Mineral Deposits39(6):1049~1062
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