摘要
延边杨金沟大型白钨矿矿床的成矿过程可划分为黄铁矿-毒砂阶段、石英-粗粒白钨矿阶段、石英-多金属硫化物-细粒白钨矿阶段以及碳酸盐阶段,其中,石英-粗粒白钨矿阶段为主成矿阶段。与粗粒白钨矿共生的石英中主要发育4种类型流体包裹体。Ⅰ型包裹体的气相组分主要由CO2、CH4和N2组成,均一温度为278.5～336.4℃,盐度(w(NaCl))为3.53%～7.72%;Ⅱ型气液两相包裹体均一温度为144.7～345.9℃,多数为190～220℃,w(NaCl)为3.05%～9.34%;Ⅲ型CO2包裹体中的气相组分均为CO2,液相中尚含少量CH4等组分;Ⅳ型含CO2三相包裹体由液态CO2、气态CO2、盐水溶液三相组成,CO2相占10%～15%,完全均一化温度为301.6～305.1℃。综合地质条件及矿床特征、包裹体显微测温和成分分析结果认为:杨金沟石英脉型白钨矿矿床的成矿流体为中高温、低盐度的NaCl-H2O-CO2(-N2)体系,初始流体主要来自酸性岩浆热液,并有地层组分的加入。成矿过程中流体发生过不混溶,并对钨的富集起到了重要作用。
The mineralizing process of the Yangjingou large scheelite deposit can be listed such four metallogenetic stages as pyrite-arsenopyrite, quart-coarse scheelite, quartz-sulphides-fine scheelite as well as carbonates stage. In order to analyze the source, features and evolution of ore-forming fluid, fluid inclusions in quartz minerals formed in the major metallogenetic stage are studied. Types of fluid inclusions include gas-rich （Ⅰ）,gas-liquid （Ⅱ）, pure-CO2 （Ⅲ） and CO2-bearing three phase （Ⅳ）. The gas phase of typeⅠinclusions is proved to be mainly composed of CO2, CH4 and N2, their homogenization temperatures vary from 278.5 to 336.4℃, with salinities （NaCl） from 3.53% to 7.72%. TypeⅡ inclusions, with ratios of gas to liquid in change from 10% to 45%, are homogenized to liquid during heating, their homogenization temperatures vary from 144.7 to 345.9℃, mainly from 190 to 220℃, salinities（NaCl） from 3.05% to 9.34%. Type Ⅲ is dominated by CO2 with minor CH4. Type Ⅳ fluid inclusions are composed of three phases （VCO2＋LCO2＋LH2O）, homogenization temperatures change from 301.6 to as 305.1℃.Comprehensive study on ore-forming condition,geological features of the deposit, compositional and microthermometric analysis of fluid inclusions leads to the conclusion that the ore-forming fluid of the Yangjingou deposit belongs to the NaCl-H2O-CO2（-N2） hydrothermal system with medium-high temperature, low salinity. It is derived from deep crust to upper mantle and mixed by ore-forming materials from the Paleozoic metamorphic strata of the Wudaogou Group which hosts scheelite-quartz veins. The immiscibility of ore-forming fluid played an important role in the metallogenetic process of Yangjingou scheelite deposit.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2010年第4期764-772,共9页
Journal of Jilin University：Earth Science Edition
基金
中国地质调查局项目(1212010070303)
吉林大学科学前沿与交叉学科创新项目(421030414422)
南京大学内生金属矿床成矿机制研究国家重点实验室开放基金(14-08-11)
