嘉鱼蛇屋山金矿热液蚀变和表生风化作用

本文按热液活动的组合顺序,阐述了早、中、晚及酸滤——氧化四个阶段的主要蚀变种类,蚀变矿物特征,共生组合及其分布,并分别讨论黄铁矿、石英、雄黄、雌黄、石油和碳化、重晶石等蚀变矿物以及风化作用在金的活化运移及沉淀中的作用。指出细粒五角十二面体、八面体、立方体或凸多面体黄铁矿的共生是金矿体的指示矿物,粗粒立方体黄铁矿不含金或含金少。硅化、碳化与金的沉淀关系密切。风化作用使金重新活化且均匀化。

HYDROTHERMAL ALTERATION AND HYPERGENIC WEATHERING OF SHEWUSHAN GOLD DEPOSIT IN JIAYU COUNTY

Shewushan gold deposit was formed by the geological processes of tectonic action-hy-drothermal alteration-weathering. This paper has discussed main kinds of alteration, features of alteration minerals, parage-netic association and their general distributions at the four stages, which are early, middle and late stage and acid filter-oxidation stage in the order of hydrothermal action, and has dis-cussed genetic mechanism of main altered minerals. The early stage is characterized by low temperature silicification and forming coarse cubic pyrite. The middle stage is main metallo-genic stage and during this stage fine polymorph pyrite, realgar and carbonization were formed. In the late stage, allotrimorphic-granular or colloform-granular pyrite, kaolinite, orpiment, calcite and petroleum were formed, Acid filter-oxidation stage happened in the pe-riod from last middle stage to late stage, and during this stage barite, marcasite and a few kaolinite were formed. Hypergenic weathering is strongly pedogenesis. Finally, this paper has respectively discussed the actions of pyrite, quartz, realgar, orpiment, barite, petroleum and carbonization and weathering during the remobilization and precipitation of gold element. It has been point out that the paragenetic association of fine grained pyritohedron pyrite is in-dex mineral for prospecting ore bodies of gold. Coarse cubic pyrite does not contain gold or contain few gold. Silicification and carbonization are in close relationship with gold precipita-tion. Weathering makes gold remobilization again and homogenization.