东天山卡拉塔格矿带红海VMS型矿床S、Pb同位素地球化学研究  

Lead and sulfur isotope studies of sulfides from Honghai VMS-type deposit in Kalatage ore belt of eastern Tianshan Mountains

作　　者：毛启贵[1] 王京彬[1] 方同辉[2] 朱江建[1] 付王伟 于明杰[4] 黄行凯[1] 

机构地区：[1]北京矿产地质研究院,北京100012 [2]有色金属矿产地质调查中心,北京100012 [3]新疆洁净能源技术研究院,新疆哈密839000 [4]中国地质大学(北京),北京100083

出　　处：《矿床地质》2015年第4期730-744,共15页Mineral Deposits

基　　金：国家"973"计划项目(编号:2014CB440803);国家科技支撑计划重点项目(编号:2011BAB06B04-03);国土资源部公益性行业科研专项经费项目(编号:201411026-1)联合资助

摘　　要：红海早古生代块状硫化物矿床是近年来在东天山新发现的典型VMS型矿床，赋存在一套早古生代海相岛弧火山岩-火山碎屑岩中，是由上部透镜状块状矿体和深部脉状-网脉状矿体组成。文章对该矿床开展了系统的S、Pb同位素地球化学研究，拟揭示其成矿物质来源。本次分析获得金属硫化物的硫同位素护。S值：黄铁矿〉闪锌矿〉黄铜矿，且接近于0‰（-0．8‰～6．0‰）；而重晶石的铲0S值为高正值（27．4‰～29．9‰），这与世界大部分VMS型矿床的硫化物830S值一致；矿床硫主要来自于下盘岛弧火山岩硫及与少量海水硫酸盐无机还原硫的混合。金属硫化物的Pb同位素组成比较集中，其中206pb／204Pb为17．886～18．144，207pb／204Pb为15．465～15．506，008pb／TMPb为37．325-37．684，硫化物Pb同位素类似于MORB亏损地幔Pb同位素特征，具有地幔和造山带来源特征，显示其金属成矿物质主要来源于矿体下盘发育的具亏损地幔特征的岛弧火山岩。总之，红海VMS矿床硫化物S、Pb同位素研究显示其成矿物质主要来自岛弧火山岩，少量来自海水，它们为深入研究VMS矿床成矿物质来源和成矿过程中流体问相互作用提供了资料。The early Paleozoic Honghai volcanogenic massive sulfide deposit, newly discovered in Eastern Tianshan Mountains, is a typical VMS deposit. The orebodies hosted in arc-related abyssal facies volcanic and volcaniclas- tic rocks consist of lenticular massive orebody in the upper part and sulfide-silicate stockwork or vein orebody in the lower part. In this paper, the authors systematically studied the sulfur and lead isotopic composition of the sulfide from the deposit so as to reveal the ore-forming material source. The sulfur isotope analyses show that δ34S valuGs gradually decrease in order of pyrite, sphalerite and chalcopyrite, and most of the values close to 0 （-0.8‰-- 6.0‰）, whereas the barite has highly positive 334S values （27.4‰, - 29.9‰）, similar to features of the VMS-type deposits in the world. A two-component mixing model between arc-related volcanic rocks sulfur and seawater reduced sulfate is suggested for the sulfur source in the Honghai deposit. The 206Pb/204Pb, 207pb/204 Pb and 208 pb/204 Pb ratios of sulfides are 17.886 -- 18.144, 15.465 -- 15.506 and 37.325 37.684, respectively, showing a narrow Pb-isotope variation, similar to features of the MOP, B-type depleted mantle derived Pb, and characterized by a two-component mixing between the mantle derived Pb and orogenic belt derived Pb. These Pb isotope characteristics indicate that the ore-forming material was mainly derived from the underlying mantle-derived arc-related volcanic rocks. Hence, the lead and sulfur isotope analyses obtained in this study indicate that the main ore-forming material source was the mantle-derived arc-related volcanic rocks with the addition of ore-forming material derived from the sea water. The results achieved by the authors offer a very important constraint on the ore-forming material source and fluid interactivity in the ore-forming process.

关 键 词：地球化学 VMS型矿床 S 、Pb同位素 红海矿床 东天山 

分 类 号：P618.31[天文地球—矿床学]