内蒙古上打井斑岩型钼矿床绿泥石特征及成矿意义  

Characteristics of Chlorites in the Shangdajing Porphyry Mo Deposit,Inner Mongolia and Their Metallogenic Implications

作　　者：葛祥坤[1] 句海玉 赵峰华[2] 范光[1] 孙思辰 艾钰洁[1] GE Xiangkun;JU Haiyu;ZHAO Fenghua;FAN Guang;SUN Sichen;AI Yujie(Beijing Research Institute of Uranium Geology,Beijing 100029;China University of Mining&Technology,Beijing 100083;State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing 100083)

机构地区：[1]核工业北京地质研究院,北京100029 [2]中国矿业大学(北京),北京100083 [3]中国地质大学(北京)地质过程与矿产资源国家重点实验室,北京100083

出　　处：《地质与勘探》2020年第4期704-713,共10页Geology and Exploration

基　　金：中核集团地矿事业部铀矿地质科研项目“基于扫描电镜的岩矿石物相定量分析方法研究”(编号:测D1706);中核集团“龙腾”2020科技创新计划项目(编号:测LTC1605-2)联合资助。

摘　　要：内蒙古劳家沟上打井斑岩型钼矿床是近年来在西拉木伦钼矿带新发现的一个矿床,其绿泥石化蚀变与钼矿化关系具有密切的时空关系。因此,对绿泥石化学成分的分析,有助于查明该矿床成矿过程的物化条件。本文采集矿区典型绿泥石样品,通过岩矿鉴定,结合绿泥石的电子探针化学成分分析,研究其特征。分析结果显示,该矿床绿泥石以富铁种属铁镁绿泥石为主,个别为铁绿泥石,揭示其形成于还原环境;绿泥石结构的离子置换主要体现为Fe、Mg间的置换;由绿泥石温度计估算得到绿泥石的形成温度为270~344℃,平均312℃;绿泥石形成机制:一为先溶蚀,后结晶;二为先溶蚀,后迁移,最后结晶。绿泥石的成分特征在一定程度上可以反映热液流体特征,绿泥石化可作为该区钼成矿的找矿标志。The Shangdajing porphyry Mo deposit is a newly discovered deposit in the Xilamulun metallogenic belt.Chlorite is the main hydrothermal alteration mineral genetically related to Mo mineralization in this district.Therefore,the analysis of the chemical composition of chlorite is helpful to determine the physical and chemical conditions of the mineralization process of the deposit.This work collected typical chlorite samples from the deposit,and utilized rock and ore identification to study the chlorite in combination with electron probe microanalysis.The results show that chlorites in this deposit are mainly iron-rich daphnite and a bit of brunsvigite,indicating they were formed in reducing environments.The main isomorphism substitutions in chlorites are the replacements between Fe and Mg.The Mg/(Fe+Mg)ratios indicate that chlorites formed in mafic environments.According to the chlorite geothermometer,the chlorites formed at the temperatures of 270~344℃(312℃on average).The formation mechanisms of chlorite are mainly in two ways,namely corrosion-crystallization and corrosion-migration-crystallization.The compositional characteristics of chlorite can reflect the characteristics of hydrothermal fluid to a certain extent,and chloritization can be used as a prospecting indicator for molybdenum mineralization in this area.

关 键 词：绿泥石 化学成分 电子探针 成矿意义 上打井钼矿 西拉木伦钼矿带 内蒙古 

分 类 号：P614[天文地球—矿床学]