藏南古堆地区锑多金属矿床成矿流体热力学与地球化学特征及其成矿启示  

Thermodynamic-Geochemical Signatures of Ore-Forming Fluids in the Gudui Sb-Polymetallic District,Southern Tibet:Implications for Sb Enrichment and Deposit Genesis

作　　者：娄元林 成明 陈武 唐侥 曾昊 陈坤 袁永盛 杨桃 LOU Yuanlin;CHENG Ming;CHEN Wu;TANG Yao;ZENG Hao;CHEN Kun;YUAN Yongsheng;YANG Tao(Institute of Mineral Resource,Chinese Academy of Geological Sciences,Beijing 100037,China;School of Earth Sciences and Resource,China University of Geosciences(Beiing),Beijing 100083,China;Changsha General Survey of Natural Resources Center,China Geological Survey,Changsha,Hunan 410600,China;Hubei Geological Bureau,Wuhan,Hubei 430022,China;Kunming General Survey of Natural Resources Center,China;Geological Survey,Kunming,Yunnan 650100,China 6.Changde Vocational Technical College,Changde,Hunan 415000,China)

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]中国地质调查局长沙自然资源综合调查中心,湖南长沙410600 [4]湖北省地质局,湖北武汉430022 [5]中国地质调查局昆明自然资源综合调查中心,云南昆明650100 [6]常德职业技术学院,湖南常德415000

出　　处：《现代地质》2025年第2期263-276,共14页Geoscience

基　　金：中国地质调查局项目(1212011121236,12120114083501,DD20230386和DD20230376)。

摘　　要：藏南古堆地区地处特提斯—喜马拉雅构造域一级构造单元之喜马拉雅片的中段,北涉雅鲁藏布江板块结合带,该区新发现系列锑多金属矿床。目前关于这些矿床的科学研究薄弱,制约对矿床成因和区域成矿规律的深入认识。本文选择该区代表性的恰嘎、那穷和卓木日矿床为研究对象,在详细查明矿床地质特征的基础上,对成矿流体展开系统研究,探讨其成分、温度、盐度、压力等物理化学条件,限定成矿流体类型,并估算成矿深度。结果表明,该区以锑为主的矿床的流体包裹体类型主要为富液相包裹体,铅锌为主的,可见有三相包裹体;主成矿温度上辉锑矿成矿温度(180~208℃)略低于铅锌矿成矿温度(203~230℃),NaCl_(eq)盐度为3.0%~9.9%;成矿流体的气体成分以CO_(2)为主,并含有部分N_(2)、CH_(4)、H_(2)O,属中低温低盐度NaCl-H_(2)O热液体系;成矿压力为33~71 MPa,成矿深度为1.2~2.6 km,形成于浅成成矿环境;成矿流体的δD_(V-SMOW)为-64.6‰~-70.2‰和-135.2‰~-129.4‰,δO_(H2)O为2.9‰~5.2‰和6.6‰~9.9‰,H、O同位素表明成矿流体具有多源性,以建造水为主,也有浅部流体的混入。综合分析认为藏南古堆地区锑多金属矿床为以建造水为主的浅成中低温热液矿床,且现锑矿的深部可能存在Au-Sb、Pb-Zn-Sb矿。The Gudui area of southern Tibet is situated in the mid-Himalayan segment of the Tethys-Himalayan tectonic domain,adjacent to the Yarlung Tsangpo suture zone in the north.A series of Sb-polymetallic deposits have been newly discovered in this region,though limited scientific research currently constrains understanding of their genesis and regional metallogenic controls.This study investigates three representative deposits(Qiaga,Naqiong,and Zhuomuri) through detailed geological characterization and systematic analysis of ore-forming fluids to constrain physicochemical conditions(composition,temperature,salinity,pressure) and metallogenic depth.Our results reveal that Sb-dominated ores contain primarily liquid-rich fluid inclusions,whereas Pb-Zn ores host three-phase(liquid-vapor-solid) inclusions.Stibnite mineralization temperatures(180-208 ℃) are slightly lower than Pb-Zn mineralization(203-230 ℃),with salinities of 3.0%-9.9% NaCl eq.The CO_2-dominated gas phase contains minor N_2,CH_4,and H_2O,consistent with a medium-low temperature,low-salinity NaCl-H_(2O) hydrothermal system.Calculated pressures(33-71 MPa) and depths(1.2-2.6 km) indicate shallow crustal mineralization.Hydrogen and oxygen isotopes reveal mixed fluid sources:δD_((V-SMOW)) values(-64.6‰ to-70.2‰ and-135.2‰ to-129.4‰) and δ~(18)O_(H_2O) values(+2.9‰ to +5.2‰ and +6.6‰ to +9.9‰) suggest formation water dominance with shallow crustal contributions.These findings demonstrate that the Gudui Sb-polymetallic deposits represent shallow epithermal systems dominated by formation waters,with vertical zonation implying potential Au-Sb and Pb-Zn-Sb mineralization at depth beneath existing Sb ores.

关 键 词：锑多金属矿床 成矿流体 流体包裹体 热力学与地球化学 古堆地区 藏南 

分 类 号：P597[天文地球—地球化学] P618.66[天文地球—地质学]