湖北嘉鱼县蛇屋山金矿硅质岩地球化学特征及成矿环境约束  

Geochemistry of Cherts from Shewushan Gold Ore Deposit in Jiayu,Hubei Province and Its Metallogenic Environmental Constraints

作　　者：徐萌萌[1] 徐广东[2] 孙祥民 朱本杰 刘蕴光[2] 肖凡[2] 许荣科[4] 徐永利[2] 李宝庆[2] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中国地质大学资源学院,湖北武汉430074 [3]湖北省地质矿产勘查开发局第四地质大队,湖北咸宁437100 [4]中国地质大学地质调查研究院,湖北武汉430074

出　　处：《现代地质》2012年第2期269-276,共8页Geoscience

基　　金：湖北省地质矿产勘查开发局科研项目(鄂地矿科研[2009]3号)"嘉鱼蛇屋山金矿原生矿富集规律及找矿预测研究"(Ky2009-3)

摘　　要：湖北蛇屋山金矿是亚洲最大的红土型金矿,矿区内硅质岩发育,覆于含矿红土层之上,并与硅化灰岩呈渐变过渡。硅质岩主要由微晶和隐晶组成,其SiO2含量为96.87%～97.90%,w(Si)/w(Al)=92.84～287.66,平均值为173,处于纯硅质岩的范畴。硅质岩样品的w(Al)/w(Al+Fe+Mn)为0.189～0.388,平均值为0.303,具热液成因硅质岩的特征。根据Al、Fe、Mn三角图的投点,认为本研究区硅质岩为热液成因硅质岩。微量元素w(Ni)/w(Co)、w(Fe)/w(Ti)、w(Ti)/w(V)、w(U)/w(Th)也说明了硅质岩具有热水沉积成因。w(Ce)/w(Ce*)为1.05～1.27,平均值为1.12,(La/Ce)N为0.84～1.12,平均值为0.98,微量元素V的含量(3.02～4.26μg/g)以及常量元素w(MnO)/w(TiO2)(1.0～2.0)都显示此研究区硅质岩具有大陆边缘硅质岩的特征。结合宏观特征,确定硅质岩有可能形成于卡林型金矿去碳酸盐化阶段,属于热液活动的产物。The Shewushan gold deposit is the largest laterite-type gold ore deposit in Asia,and authors discover that cherts covered on the top of the red soil in the gold ore deposit,showing a gradual transition relationship with the silicified limestone.The analysis of cherts approves that the SiO2 content is from 96.87% to 97.90%,and that the Si/Al ratio ranges from 92.84 to 287.66 with average value of 173,therefore,the cherts could be classified as pure cherts.The Al/(Al+Fe+Mn)ratios of chert samples in the research area are between 0.189 and 0.388,and the average value is 0.303,implying that the cherts is of hydrogenous genesis.Al-Fe-Mn diagram shows that the cherts is also hydrothermal type,and the ratios of Ni/Co,Fe/Ti,Ti/V and U/Th show that cherts from Shewushan are hydrothermally sedimentary origin.The ratios of Ce/Ce* and(La/Ce)N is 1.05-1.27 and 0.84-1.12 with average value of 1.12 and 0.98,respectively.The trace element V content is 3.02-4.26 μg/g and the ratio of MnO/TiO2 is 1.0-2.0,which indicated that the radiolarian chert formed in transitional environment of continental margin basin.Combining with the macro characteristics,we regard that cherts probably formed in the Carlin-type gold's stage of eliminate carbonatization,which are the product of hydrothermal activity.

关 键 词：硅质岩 地球化学 沉积环境 蛇屋山金矿 湖北 

分 类 号：P618.5[天文地球—矿床学]