新疆小热泉子铜(锌)矿床同位素地球化学研究及其意义  

Isotopic Geochemistry of the Xiaorequanzi Copper(zinc) Deposit in Xinjiang and Its Significance

作　　者：刘申态[1,2,3] 吕新彪[1,2] 曹晓峰[1,2] 张平[1,2] 邓杰[1,2] 刘智[1] 

机构地区：[1]中国地质大学(武汉)资源学院,湖北武汉430074 [2]中国地质大学(武汉)地质过程与矿产资源国家重点实验室,湖北武汉430074 [3]西部矿业股份有限公司,青海西宁810001

出　　处：《地质与勘探》2011年第4期624-632,共9页Geology and Exploration

基　　金："十一五"国家科技支撑计划新疆305项目<东天山-北山成矿带整体研究及找矿靶区优选评价>(编号:2007BAB25B04)资助的成果

摘　　要：小热泉子铜(锌)矿床位于准噶尔板块与塔里木板块对接带北侧的哈尔力克-大南湖晚古生代陆源岛弧带。通过同位素地球化学研究,石英中δ18O在6.5‰～10‰之间,校正后石英和闪锌矿中流体的δ18OH2O为-2.95‰～1.73‰,包裹体中δDH2O为-105‰～-66‰;结合矿区基本地质特征,成矿流体很有可能为次火山热液与古海水的混合流体相互作用的结果;矿石中硫化物的硫同位素组成分布范围3.1‰～13.4‰之间,具有"双峰式"特征,峰值主要为4‰～7‰和11‰～12‰,早期以黄铁矿为主的硫同位素组成与古海水硫酸盐关系密切,晚期硫化物的硫同位素可能来源于火山碎屑岩中硫和古海水硫酸盐还原硫不同程度混合的结果;硫化物的铅同位素组成:206Pb/204Pb值变化在17.669～17.788之间,平均值17.719,207Pb/204Pb值变化在15.360～15.495之间,平均值15.424,208Pb/204Pb值变化为37.279～37.525之间,平均值37.396,μ值介于9.07～9.34之间,Th/U值为3.56～3.67之间,49.53<△α<62.78,3.59<△β<13.10,12.51<△γ<24.47,具有典型的壳幔混合铅的特征。The Xiaorequanzi copper （zinc） deposit is situated in the late Palaeozoic Haerlike-Dananhu island-arc zone north to the convergence belt between the Junggar plate and the Tarim plate. The study of isotope geochemistry shows that the δ^18O value of quarts is 6.5‰-10‰ from the quart sulfide veins, and the δ^18O value of fluid from quarts and sphalerite is 0. 1‰-1.73‰. The δDH2o value in the fluid inclusions is -105‰ — -66%0. Combined with the geological characteristics of the ore district, the metallogenic fluids may result from the interaction of subvolcanic hydrothermal fluids with paleo-sea water. The δ^34S value of the sulfide is 3. l‰ - 13.4‰, which has the bimodal character, in which one peak value is 4‰ -7‰, and the other is 11‰ -12‰. The early S isotopic composition dominated by pyrite has a close relationship with the sulphate from paleosea water, while the late S iso- tope from sulphide resulted from different grades of interaction of S from pyroclastic rock with reducing S in paleosea water. The ^206Pb/^204Pb ratio is 17. 669-17. 798, 17.7188 on average, the ^207 pb/2e4 Pb ratio is 15.36 - 15. 495, 15. 4243 on average, and the ^208 pb/^204 Pb ratio is 37. 279 - 37. 525, 37. 3958 on average, respectively. The/x value is g.07 -9.34,the Th/U ratio 3.56 -3.67, 49.53〈△α〈62.78,3.59〈△β〈13.10 and 12,51〈△γ〈24. 47, showing typical crust-mantle-derived Pb isotopic characteristics.

关 键 词：氢氧同位素 硫同位素 铅同位素 铅锌矿 小热泉子 新疆 

分 类 号：P618.41[天文地球—矿床学]