东昆仑东段扎麻山铜铅锌多金属矿床成因研究--来自流体包裹体及稳定同位素的指示  

Genesis of the Zhamashan Cu-Pb-Zn Polymetallic Deposit in the Eastern Section of East Kunlun:Indications from Fluid Inclusions and Stable Isotopes

作　　者：张文昭 夏楚林[1] 宋芊[1] 甄士坤 全长恩 Zhang Wenzhao;Xia Chulin;Song Qian;Zhen Shikun;Quan Changen(Department of Geological Engineering,Qinghai University,Xining,Qinghai,810016,China)

机构地区：[1]青海大学地质工程系,青海西宁810016

出　　处：《新疆地质》2022年第2期211-217,共7页Xinjiang Geology

基　　金：青海省科技计划应用基础研究项目东昆仑东段与岩浆-火山热液有关的铜-铅-锌-银多金属成矿系统形成及找矿方向研究(2020-ZJ-762)资助。

摘　　要：扎麻山铜铅锌多金属矿床位于东昆仑成矿带东段都兰-鄂拉山成矿亚带,矿体受NE向及SW向断裂带控制明显,含矿地层为一套陆相喷溢-喷发相火山岩。通过对含矿火山岩及近矿石英脉样品进行矿相学与流体地球化学分析结果显示:成矿流体包裹体均一温度集中分布在190℃~350℃,盐度变化范围集中于1~5wt%NaCl,成矿流体属中温、低盐度流体;O同位素数据显示,矿床成矿后期遭地下水热液交代蚀变作用;S,Pb同位素数据显示,矿区成矿物质来源较单一,并具一定程度的壳幔混合特征;成矿过程可划分为石英-多金属硫化物阶段(阶段Ⅰ)和石英-碳酸盐阶段(阶段Ⅱ)2个阶段。据流体包裹体成矿均一压力与成矿深度关系计算,该矿床成矿深度为0.568~0.806 km。研究认为,扎麻山矿区铜多金属矿床成矿流体来源为以火山热液为主、后期地下水热液参与的混合流体,成因类型为产于陆相火山岩中的中温、低盐度浅成火山热液矿床。The Zhamashan Cu-Pb-Zn polymetallic deposit is located in the Dulan-Elashan metallogenic subbelt in the eastern part of the East Kunlun metallogenic belt.The orebody is obviously controlled by NE and NW trending fault zones,and the ore-bearing strata are a set of continental efflux-eruptive volcanic rocks.Through mineralogical and fluid geochemical analysis of ore-bearing volcanic rocks and near-ore veins,the results show that:The homogenization tem-perature of ore-forming fluid inclusions concentrates between 190℃~350℃and the salinity varies between 1~5wt%Na-Cl.The ore-forming fluid belongs to a medium temperature and low salinity fluid.The oxygen isotope data show that the late mineralization period was affected by the metasomatic alteration of groundwater hydrothermal solution.The S and Pb isotopic data show that the source of ore-forming materials in the mining area is relatively single,and the ore-forming materials have the characteristics of crust-mantle mixing to a certain extent.The ore-forming process can be divided into two stages:quartz-polymetallic sulfide stage(stageⅠ)and quartz-carbonate stage(stageⅡ).The ore-forming depth of the deposit is 0.568~0.806km according to the calculation of the relationship between the ore-forming pressure and depth of the fluid inclusions.It is concluded that the ore-forming fluid of the copper polymetallic deposit in Zhamashan mining area is derived from the mixed fluid with mainly volcanic hydrothermal fluid and later groundwater hydrothermal fluid,and the genetic type is the epivolcanic hydrothermal deposit with medium temperature and low salinity in continental vol-canic rocks.

关 键 词：东昆仑东段 扎麻山铜铅锌多金属矿 流体包裹体 成矿物质来源 

分 类 号：P618.41[天文地球—矿床学] P618.42[天文地球—地质学]