八卦庙大型金矿床稀土元素地球化学研究

REE GEOCHEMISTRY OF BAGUAMIAO GOLD DEPOSIT

八卦庙大型金矿床是秦岭造山带中的一种与碳酸盐岩有关的中温热液矿床。本文系统总结了该矿床的稀土元素地球化学特征，对矿石、围岩、含金石英脉、酸性岩脉、铁的硫化物中的稀土元素组成、关系及成因进行了分析研究，论证了这个金矿床的形成与围岩、酸性岩脉、地壳深部金的矿源层有关。在此基础上应用简化了的Ｇｒｅｓｅｎｓ方程－Ｇｒａｎｔ方法讨论了热液蚀变过程中稀土元素地球化学行为，并分析了样品中出现Ｃｅ和Ｅｕ异常的原因，他们是沉积环境的指示剂。从稀土组成、矿物共生等探讨了金矿的成矿物质是以深源为主的多来源。

The Baguamiao gold deposit is found as a new kind of mesothermal gold deposit related to carbonate in the Qinling orogenic belt. In this paper, the REE geochemical characteristics of various representive samples including wall rock, ore, gold-bearing quartz vein, acidic vein and iron sulfides in the Baguamiao gold deposit are comprehensively summarized. The results show that gold has good relations with wall rock, acidic veins, and deep-seated gold-rich source beds. With respect to REE pattern comparison and application of Grant's isocon method, it is considered that REE is of relative immobilities during metasomatic alteration.Europium and cerium anomalies in wall rock and ore were used to discuss features of the diagenetic and tectonic environment. The gold material sources are of multi-sources, mainly deep-seated gold-rich source beds with respect of REE and mineral paragenesis etc.