青海省瓦勒尕金矿热液成矿作用——来自流体包裹体的证据  

Hydrothermal mineralization of the Walega gold deposit in Qinghai Province:Evidence from fluid inclusion characteristics

作　　者：林诗婷 罗红玲[1] 梁改忠 杨奎锋[2,3] LIN Shi-ting;LUO Hong-ling;LIANG Gai-zhong;YANG Kui-feng(College of Geoscience and Surveying Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [2]中国科学院矿产资源研究重点实验室,中国科学院地质与地球物理研究所,北京100029 [3]中国科学院大学地球与行星科学学院,北京100049

出　　处：《矿物岩石地球化学通报》2023年第6期1398-1409,共12页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金资助项目(40902065);第二次青藏高原科学考察项目(STEP)(2019QZKK0801)。

摘　　要：为厘清青海省瓦勒尕金矿的成矿流体特征、来源及其演化,对该金矿的热液阶段进行了划分,并开展了较系统的流体包裹体岩相学观察、显微测温、激光拉曼成分分析。结果显示,热液过程可划分为石英-黄铁矿、石英-多金属硫化物、石英-毒砂和石英-方解石四个阶段;流体包裹体主要有CO_(2)-H_(2)O、H_(2)O和CO_(2)三种类型;气相成分主要为CO_(2)和CH4;成矿流体均一温度为124~353℃,盐度为3.52%~16.8%NaCleqv,密度为0.64~1.0 g/cm^(3),具有富CO_(2)、中低温、中低盐度、低密度的特征。结合已有的成矿流体的氢、氧同位素组成及硫化物S、Pb同位素组成,认为矿床的成矿物质主要源于岩浆热液,成矿过程中有变质热液、大气降水的混入,成矿流体具有地幔、壳源混合的特征。In order to clarify the characteristics,origin and evolution of the ore-forming fluid of the Walega gold deposit in Qinghai Province,in this paper,we have made a detailed classification of hydrothermal stages of the Walega gold deposit and then undertaken relatively systematic petrographic observation,microthermometry,and compositional analysis of fluid inclusions by laser raman microprobe spectroscopy.Four stages,including the quartz-pyrite,quartz-polymetallic sulphides,quartz-arsenopyrite,and quartz-calcite stages,of the hydrothermal process have been classified.The main types of fluid inclusions include the CO_(2)-H_(2)O fluid inclusion,H_(2)O fluid inclusion,and CO_(2)fluid inclusion.The fluid inclusions have main gas phase components of CO_(2)and CH4,homogenization temperatures of 124~353℃,salinities of 3.52%~16.8%NaCleqv,and densities of 0.64~1.0 g/cm^(3).They are characterized with CO_(2)-rich,medium to low temperatures,medium to low salinities and low densities.Combined with the hydrogen-oxygen isotopic compositions of the ore-forming fluids and sulfur and lead isotopic composition of sulfides,it is believed that the ore-forming material and fluid were mainly sourced from the magmatic hydrothermal fluid which had been mixed with metamorphic hydrothermal fluids and meteoric water in the mineralization process and the ore-forming fluid was characterised with a mixture of mantle and crustal sources.

关 键 词：瓦勒尕金矿 成矿流体 流体包裹体 成矿物质来源 

分 类 号：P618.51[天文地球—矿床学]