新疆阿舍勒块状硫化物矿床成矿特征及形成环境  

GEOLOGICAL CHARACTERISTICS AND METALLOGENIC ENVIRONMENT OF THE ASHELE VOLCANOGENIC MASSIVE SULFIDE DEPOSIT, XINJIANG

作　　者：贾群子[1] 

机构地区：[1]中国地质科学院西安地质矿产研究所

出　　处：《矿床地质》1996年第3期267-277,共11页Mineral Deposits

摘　　要：阿舍勒块状硫化物矿床位于阿尔泰华力西地槽系南缘。容矿岩石为中、下泥盆统富钠的火山岩系，为双峰式火山岩组合，系弧后扩张背景下的产物。矿床具双层结构，并具明显的垂向分带和侧向分带。矿体下盘火山岩发生了强烈地蚀变作用，形成由石英＋绢云母＋绿泥石±黄铁矿组成的半整合蚀变带。同位素研究表明，硫由海水硫酸盐和岩石中硫化物所提供，铅具深源的特征。通过对比。The recently discovered Ashele volcanogenic massive sulfide deposit, a large sized copper zinc deposit in Xinjiang, lies on the southern margin of Altay eugeosynclinal zone It occurs in the Lower Middle Devonian soda rich volcanics series, and is associated with rhyolitic rocks of the bimodal basalt rhyolite volcanic suite According to features of volcanic rocks, it is concluded that the deposit was formed in a back arc spreading basin setting The deposit shows a lenticular morphology of a stratiform massive sulfide zone overlying a disseminated stockwork sulfide zone Deformation resulted in conversion of the lens into an isoclinal overturned syncline, with sulfides thickening in the fold axes and thinning in the limbs The deposit exhibits distinct vertical and lateral zoning, and in upward succession, there exists the ore zonation of pyrite chalcopyrite pyrite→copper zinc pyrite→polymetals→barite polymetals→barite, which is similar to things of the kuroko deposits The Cu/Zn ratios increase from 0 34 in massive Cu/Zn pyrite zone through 3 8 in polymetallic zone to 8 6 in barite polymetallic zone Below the massive sulfides, there is an semiconformable footwall alteration zone consisting of quartz, sericite, chlorite and pyrite The alteration zone is characterized by depletion of Na and enrichment of Mg, K, and existence of negative Eu anomalies Sulfur isotope studies of the Ashele deposit indicates a combined source of reduced seawater sulfate and volcanic sulfur Lead isotopes suggest that ore materials were derived from the mantle or the lower crust

关 键 词：成矿特征 形成环境 块状硫化物矿床 

分 类 号：P612[天文地球—矿床学]