伊朗扎格罗斯碰撞造山带马拉耶尔-伊斯法罕碳酸盐岩容矿铅锌成矿带——矿床基本特征与成因类型  

The Malayer-Esfahan Carbonate-Hosted Pb-Zn Metallogenic Belt in the Zagros Collisional Orogen of Iran:Characteristics and Genetic Types

作　　者：刘英超[1] 宋玉财[1] 侯增谦[1] 杨竹森[2] 张洪瑞[1] 马旺[3] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质科学院矿产资源研究所,北京100037 [3]中国地质大学地球科学与资源学院,北京100083

出　　处：《地质学报》2015年第9期1573-1594,共22页Acta Geologica Sinica

基　　金：国家"973"项目(编号2011CB403104);国家自然科学基金项目(编号41403043;41320104004;41273050;41302067);中央级公益性基本业务费专项基金项目(编号J1314);中国地质调查局项目(编号1212011220908);国际地质对比计划项目(编号IGCP/SIDA-600)联合资助的成果

摘　　要：伊朗马拉耶尔-伊斯法罕碳酸盐岩容矿铅锌成矿带,地处扎格罗斯碰撞造山带内陆的萨南达杰-锡尔詹中生代岩浆变质带构造转换区,带内发育丰富的碳酸盐岩容矿铅锌矿床,是伊朗境内重要的铅锌产出基地。综合分析表明,该带内的铅锌矿床形成于新生代古近纪早期,发育在阿拉伯板块-欧亚大陆板块碰撞造山阶段,其形成和区域上逆冲-走滑断层、走滑拉分盆地等压扭性构造密切相关。成矿带各矿区矿体多发育在区域逆冲断层上下盘,赋存于下白垩统碳酸盐岩内,受与逆断层相关的次级断层、岩性分界面等要素控制,总体以层控形式产出。矿种组合以Zn-Pb为主,少量矿区出现Cu。硫化物主体为闪锌矿、方铅矿、黄铁矿,出现少量黄铜矿和黝铜矿,非硫化物以石英、白云石、方解石、重晶石为主。矿化以脉体充填或热液矿物交代充填为主要形式,脉状、浸染状、块状为主要矿石构造,强硅化和白云石化为主要蚀变特征。热液矿物仅发育两相盐水包裹体,成矿流体温度介于90~257℃,盐度介于0%~24%NaCl eq.,总体反映了中低温高盐度盆地卤水来源和另一种具中低温中低盐度特征的流体来源。不同矿区硫同位素组合差异较大,其中IranKuh矿区硫化物硫同位素为负值,介于-10‰^-3‰,重晶石硫同位素为正值,介于14‰~19‰,Emarat矿区硫化物硫同位素为正值,介于2‰~15‰,总体反映了生物还原或有机质热还原赋矿碳酸盐岩地层封存水中溶解的早白垩世海相硫酸盐为主要还原硫来源。方铅矿铅同位素组成在带内各矿区差别不大(206Pb/204Pb介于18.389~18.471,207Pb/204Pb介于15.628~15.659,208Pb/204Pb介于38.470~38.650),推测成矿金属物质来自区域整套的上地壳地层。该矿带碳酸盐岩容矿铅锌矿床为一套与岩浆作用无关的后生铅锌矿床,以世界上的矿床类型划分可在大范畴上归入MVT铅锌矿床,但是,这些矿床形�The Malayer-Esfahan carbonate-hosted Pb-Zn metallogenic belt, located in the Sanandaj-Sirjan Zone （SSZ） which is the interior of Zagros collisonal orogen, is the biggest reservoir of Pb and Zn metals in Iran for the abundant carbonate-hosted Pb-Zn deposits forming in it. By comprehensive analysis, the authors pointed out that the carbonate-hosted Pb-Zn deposits in the Malayer-Esfahan belt deposited in early Paleogene when the Arabian plate was colliding with the Eurasia plate and these deposits had closed relationship with the dextral transpression structures （e. g. Thrust faults, slip faults and strike-slip pull apart basins）. Ore bodies in different deposits are hosted in the lower Craterous carbonate hosts in the hanging wall or the foot wall of the regional thrust faults, they are controlled by the secondary faults and facies transitions related with the regional thrust faults, and they are strata-bound overall. The metals have Pb＋Zn associations in most of the deposits, though minor Cu occurs in individual deposit. Sphalerite, galena, pyrite and minor chalcopyrite and tetrahedrite are the sulfide assemblages, and quartz, dolomite, calcite and barite are the non-sulfide assemblages. They occur in veins or hydrothermal replacements. Vein, dissemination and massive are the main ore structures. Strong silicifation and dolomitization are the main alternation. The fluid inclusions in the hydrothermal minerals are just two-phase ones with liquid and vapor. The homogenization temperatures of them are between 90℃ and 257℃, and the salinities of them are between 0 G NaCl eq. and 24 % NaCl eq. , both of which indicate that a fluid source of basional brines with middle to low temperature and high salinity and another fluid source with middle to low temperature and middle to low salinity. The sulfur isotopic compositions in different deposits are different. The data of sulfur isotopes of sulfide in Irankuh deposit are negative （--10‰～--3‰, of barite are positive （14‰～19‰） and of sulfide in

关 键 词：碳酸盐岩容矿铅锌矿床 类MVT铅锌矿床 马拉耶尔-伊斯法罕成矿带 扎格罗斯碰撞造山带 伊朗 

分 类 号：P618.4[天文地球—矿床学]