九华山花岗岩体钠交代特征与成矿作用的初步探讨

THE FEATURES OF HYDROTHERMAL SODIUM METASOMATISM AND ITS SIGNIFICANCE OF URANIUM METALLOGENESIS IN JIUHUASHAN GRANITE MASSIF,SOUTH CHINA

本文分析和归纳了花岗岩、钠交代岩的产出条件、蚀变特征,论述了岩体中热液活动阶段划分及蚀变流体的演化。探讨了钠交代作用及其蚀变岩石对铍铀成矿所起的控制作用。

In this paper, positions of the glanite and sodium metasomatite, feature and zonation of metasomatic alteration minerals are analysed. and the composition character and evolu- tion of alteration solution have been revealed. Controlling processes of solium metasoma- tism and sodium metasomatite for uranium-bery(?)l(?)um mineralization are discussed. 1. The granite was obviously superimposed and reformed by sodium carbonate hydrothermal so- lution in alteration zones. Based on the study of K-feldspar and its albitization, it is be- lieved that the granitic magma is rich in Si and K. Albitization took place as a result of geological process of sodium-rich and calcium-rich hydrothermal fluid. 2. At the early stage, with the disassociation of minerals a portion of uranium was derived from wall rocks (protolith) by hydrotheimal solution. 3. The main uranium mineralization occurred at the late stage of the continuous hydrothermal activities. Uranium was coprecipitated with metal sulfides.