特提斯喜马拉雅构造带东段拉琼锑金矿床流体包裹体特征及地质意义  

Characteristics of fluid inclusion and geological significance of Laqiong antimony-gold deposit in the eastern part of the Tethys Himalayan structural belt,China

作　　者：刘行 邹灏[1,2] 李阳 蒋修未[1] 陈海锋 李敏 李蝶 LIU Hang;ZOU Hao;LI Yang;JIANG Xiuwei;CHEN Haifeng;LI Min;LI Die(College of Earth Sciences,Chengdu University of Technology,Chengdu 610059,China;Key Laboratory of Tectonic Mineralization and Accumulation,Ministry of Natural Resources,Chengdu 610059,China)

机构地区：[1]成都理工大学地球科学学院,成都610059 [2]自然资源部构造成矿成藏重点实验室,成都610059

出　　处：《成都理工大学学报（自然科学版）》2020年第3期290-306,共17页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家自然科学基金项目(41702108);四川省教育厅重大培育项目(18CZ0009);成都理工大学珠峰科研项目。

摘　　要：拉琼锑金矿床位于青藏高原南部的特提斯喜马拉雅构造带东段,印度河-雅鲁藏布江缝合带与藏南拆离系断裂带之间。为了探讨拉琼锑金矿床的沉淀机制以及成矿作用过程,对流体包裹体的岩相学、成矿温度以及成分进行研究。结果表明:流体包裹体类型分为富液H2O两相包裹体(Ⅰa)、富气H2O两相包裹体(Ⅰb)、含CO2-H2O三相包裹体(Ⅱ类)、纯液相H2O包裹(Ⅲ类),同一视域内可见CO2-H2O三相包裹体和H2O两相包裹体共存。从早期到晚期各阶段流体特征发生一系列变化,平均均一温度分别为259.4℃、206.8℃、170.0℃、120.1℃,盐度(NaCl质量分数)分别为3.87%~8.41%、2.07%~8.23%、2.07%~7.45%、1.91%~4.35%,估算的密度整体为0.79~1.05g/cm^3,平均成矿压力为27.8MPa,平均成矿深度为2.78km。激光拉曼光谱分析表明成矿流体成分以H2O、CO2以及CO3^2-为主,有少量CH4、HS-。综合推断拉琼锑金矿床是流体混合作用和冷却降温作用共同形成的中低温、低盐度、中-浅成的矿床,其成矿作用过程可能与特提斯喜马拉雅构造带的穹隆与断裂带密切相关。The lithography,metallogenic temperature and composition of fluid inclusions from the medium-sized Laqiong antimony-gold deposit in the eastern Tethys Himalayan tectonic belt in the south Qinghai-Tibet Plateau were studied in order to explore the precipitation mechanism and metallogenic process of the deposit.Fluid inclusions in the gold deposit can be classified into rich liquid H2O two-phase inclusions(Ⅰa),rich gas H2O two-phase inclusions(Ⅰb),CO2,H2O bearing three-phase inclusions(Ⅱ class),pure liquid H2O inclusion(Ⅲ class),and the coexisting of H2O bearing three-phase inclusions and H2O two-phase inclusions.From early to late stages,a series of changes occurred in fluid inclusions.Analysis showed that the average uniform temperatures were 259.4℃,206.8℃,170.0℃ and 170.0℃,successively;salinity(mass fraction of NaCl)were 3.87%~3.87%,2.07%~8.23%,2.07%~2.07%,1.91%~4.35%.The estimated overall density was 0.79~1.05g/cm^3 and the average metallogenic pressure was 27.8 MPa with an average metallogenic depth of 2.78km.Laser Raman spectroscopy analysis indicated that the main components of the oreforming fluid were H2O,CO2 and CO3^2-,with a small amount of CH4 and HS-.It is considered that the Laqiong antimony-gold deposit is a medium-low temperature,low-salinity,medium-shallow deposit formed by fluid mixing and cooling,and the mineralization process is likely to be closely related to the dome and fault zone of the Tethys Himalayan structural belt.

关 键 词：特提斯喜马拉雅 锑金矿床 流体包裹体 激光拉曼 穹隆 

分 类 号：P618.66[天文地球—矿床学] P618.51[天文地球—地质学]