胶东金青顶金矿床围岩蚀变特征与金矿化

金青顶金矿围岩蚀变发育,从近矿到远矿依次发育黄铁绢英岩化、绢英岩化和钾长石化,并呈近似对称的带状分布.由地表至深部,钾长石化蚀变强度有增大的趋势,局部出现膨大收缩的豆英状构造特征；绢英岩化浅部较发育,深部反复尖灭重现；黄铁绢英岩化带宽度很窄,仅浅部独立成带产出.各类蚀变过程中与Au成矿相关的Ag、As、Hg等元素含量增加,蚀变围岩中成矿元素以带入为主,推测围岩的主要作用是冷却成矿热液,并改变其化学性质,使成矿物质在有利的容矿空间沉淀富集,而非提供成矿物质的母岩.

Wall Rock Alteration and Gold Mineralization in the Jinqingding Gold Deposit, Eastern Shandong Province

The study of wall rock alteration in the Jinqingding gold deposit shows that there are pyritization silicification-sericitization,silicification-sericitization and potash-alteration from proximal to distal.It is showed that,from shallow to deep strata,the alteration zone of potassic become wider and the beanpoded structure occurs in some places,and that silicification-sericitization is developed commonly in the shallow stratum but repeatedly disappears in deep strata,and that pyritization silicification-sericitization only occurs in the shallow stratum.The analytical results of Au related trace elements(Ag,As,Hg) indicated that their contents increase gradually from the unaltered granite to the slightly altered granite and to the strongly altered granite in the ore body.It is concluded that wall rock is not the main source of the ore-forming material,and that the main role of the wall rock is to cause chemical property changes of the hydrothermal fluid by cooling it down and to contribute to ore formation at certain special spaces.