570矿床主要矿石矿物的成分特征

本文对５７０矿床的主要矿石矿物（沥青铀矿、铀石、钛铀矿及胶硫钼矿）的化学组成进行了研究。沥青铀矿的铀含量较高（ＵＯ２＋ＵＯ３）＝８４．４％￣９１％，并含有一定量的Ｃａ、Ｓｉ、Ｐ和Ｔｉ等，而Ｔｈ和ＲＥＥ的含量低，表明沥青铀矿的低温成因。在电镜下观察到钛铀矿与钛的氧化（金红石或锐钛矿）成交代关系，说明钛铀矿是交代成因的。胶硫钼矿中的银含量很高（０．５％￣１．６％），是该矿床伴生银的富集矿物及携带矿物，

COMPOSITIONAL CHARACTERISTICS OF THE MAIN OREMINERALS IN DEPOSIT 570

The compositional characteristics of main ore minerals (pitchblende, coffinite, brannerite andjordisite) in Deposit 570 are described in this paper. In pitchblende the content of U is relativelyhigh with some amount of Ca, Pb and Ti, but the contents of Th and REE are very low. Thesecompositional characteristics show that the pitchblende was formed at low temperature. Electronmicroscopic examination shows that Ti-oxide (rutile or anatase) is replaced by brannerite, indicat-ing the metasomatic origin of brannerite. The content of silver in jordisites is very high (0. 5% ~1. 6% ), which is the concentrating and carrier mineral of associated silver in this deposit. Silver isuniformly distributed in jordisite. It is the first time that such a high content of silver has beenfound in jordisite.