摘要
延边东部五道沟矿床内的钨矿体主要呈平行脉状赋存于华力西晚期蚀变花岗闪长岩中,与相邻的杨金沟大型钨矿相比,具有矿脉数量少、单脉厚度大和品位高的特点;矿石中金属矿物以白钨矿为主,呈团块状、粗粒浸染状、细脉状产于石英脉及碎裂蚀变围岩中,具有热液脉型矿床的矿化特征。主成矿阶段形成的粗粒白钨矿及石英颗粒中主要发育气液两相包裹体,白钨矿颗粒中尚含少量的含CO2三相包裹体。石英中气液两相包裹体均一温度主要介于171.2～268.0℃,热液盐度(w(NaCl))为0.70%～10.74%;白钨矿中气液两相包裹体的均一温度变化范围为209.6～253.3℃,热液盐度为1.39%～8.67%;白钨矿中2个含CO2三相包裹体完全均一温度分别为287.2℃和294.7℃。结合单个包裹体气相组分分析,认为五道沟白钨矿矿床的成矿流体为中温、低盐度的NaCl-H2O-CO2体系,并含一定数量的N2等气体。该矿床与杨金沟大型钨矿综合对比表明:两矿床具有相似的成矿地质背景和控矿条件,围岩蚀变、矿石矿物组成、矿石组构及白钨矿赋存状态等矿化特征基本相同,不同赋矿围岩中含矿构造性质不同应是两矿区钨矿体形态、产状和规模差异的主控因素。
Tungsten mineralization of Wudaogou ore deposit occurs mainly in the Late Indosinian altered granodiorite as parallel scheelite-quartz veins.Compared with the adjacent Yangjingou ore deposit,some of the ore veins in Wudaogou are characterized by large thickness and high ore grade.As the most important ore mineral,the scheelite grains are distributed in massive,coarse-grained disseminated and veinlet forms in quartz veins and altered host rocks.Fluid inclusions are dominated by gas-liquid ones in both scheelite and quartz grains formed at the major ore-forming stage.Moreover,two CO2-bearing three-phase inclusions are also observed in scheelite grains.Homogenization temperatures and salinities of gas-liquid inclusions in quartz vary mainly from 171.2 to 268.0℃ and from 0.70%NaCl to 10.74%NaCl,respectively,whereas those in scheelite grains vary from 209.6 to 253.3℃ and from 1.39%NaCl to 8.67%NaCl respectively.Homogenization temperatures of two CO2-bearing three-phase inclusions in the scheelite are 287.2 and 294.7℃.A comprehensive study of compositional and microthermometric analytical results of fluid inclusions has led to the conclusion that the ore-forming fluid from Wudaogou ore deposit belongs to the NaCl-H2O-CO2 hydrothermal system with medium temperature,low salinity and minor N2.A comparative study of Wudaogou and Yangjingou scheelite deposits indicates that they were formed in similar geological settings with the same hydrothermal alteration,mineral assemblage,ore textures and structures as well as modes of occurrence of the scheelite.The two ore deposits are genetically related to a common hydrothermal scheelite mineralization event.Since the two ore deposits have different ore-controlling structures,the ore bodies in the two ore deposits have different attitudes,shapes and sizes.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2011年第6期1736-1744,共9页
Journal of Jilin University：Earth Science Edition
基金
中国地质调查局项目(1212011085485)
吉林大学科学前沿与交叉学科创新项目(200903025)
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)
关键词
地质特征
流体包裹体
矿床成因
五道沟钨矿床
延边地区
geological characteristics
fluid inclusion
ore genesis
Wudaogou scheelite deposit
eastern Yanbian area
