相山大型火山岩热液铀矿床成矿深部轨迹及其模拟实验

Analysis on Deep Metallogenic Trace and Simulation Experiment in Xiangshan Large-scale Volcanic Hydrothermal Type Uranium Deposit

在野外地质研究基础上实施系列实验,从野外建立成矿深部轨迹模型转化为深部轨迹实验模型,在岩浆阶段首次在国内实验得出流体与熔体铀、钍分配系数,探讨在岩浆阶段铀、钍、钾的地球化学行为;在热液蚀变阶段实验证明铀与钠的亲密关系;成矿阶段铀与钾的关系,表现出钾、钠不相容和钾、钠更替规律。实验表明,基底变质岩和含矿主岩铀溶解随压力增加而增加,地下深部成矿远景愈好。同时矿石Pb,Sr,Nd,He同位素组成示踪共同显示,矿源来自火山岩和基底;火山热液与深部幔汁联合作用促成铀迁移富集多次成矿直至成为富大铀矿。

Based on series experiments on field geologic analysis,and associated with deep metallogenic trace experiment model transformed from establishment of field deep metallogenic trace model,this paper come to the conclusion that distribution coefficients of U Th first domestic from the magmatic experiment,and then discuss the geochemical behaviors of U、Th、K during magmatic evolution stage. The experiment shows that close relationship between U and Na during the hydrothermal alteration stage; and relationship between U and K during metallogenic stage,which prove that U K are incompatible and regularity of variation between K and Na. The conclusion of uranium dissolving ability increased accompany with pressure increasing in basement metamorphic rocks and host rocks,is obtained from this experiment,which indicate a good deep metallogenic prospect. Furthermore,Pb、Sr、Nd、He isotopes show that the volcanic rocks and basement rocks are ore source beds; due to the combined functions of volcanic hydrothermal and mantle ichor,uranium undergo multi-migration and enrichment and finally concentrated to large rich deposit.