摘要
阿布纳布锑矿床系雅鲁藏布江缝合带所发现的首例大型锑矿床, 但其矿床成因尚未厘定。本文基于对黄铁矿、毒砂、辉锑矿等主要硫化物矿相学、原位微量元素与S同位素组成, 探讨矿床成矿流体来源和性质, 以揭示矿床成因。矿区主要赋矿围岩为辉长岩, 其强硅化部位形成锑矿体。阿布纳布锑矿床成矿过程可划分为一个热液成矿期, 包含四个矿化阶段: 碳酸盐-硫化物阶段、石英(粗粒)-硫化物阶段(PyⅡ、PyⅡ、ApyⅡ)、石英-辉锑矿阶段(ApyⅡ、Stb)和石英(细粒)-硫化物阶段。其中, 石英-辉锑矿阶段为主成矿阶段。各阶段黄铁矿、毒砂、辉锑矿微区Co、Bi含量和δEu等特征指示, 阿布纳布锑矿床成矿流体在黄铁矿形成时具有较高的温度, 随着流体温度的逐渐降低使得毒砂、辉锑矿开始结晶并沉淀成矿;随着成矿作用的进行, 流体由初始弱氧化条件逐渐转变为较强还原环境, 最终导致辉锑矿大量沉淀。成矿流体温度的降低与流体由氧化向强还原环境的转变, 系矿化元素富集并沉淀成矿的两重重要机制。另外, 阿布纳布锑矿床属热液成因, 矿床成矿流体源自岩浆且初始成矿流体具有明显富As和成矿元素Sb的特征, 高含量的Sb和As组成为成矿奠定了物质基础。辉锑矿中As、Cu、Pb之间存在2Sb^(3+)↔Cu^(+)+Pb^(2+)+As^(3+)的置换机制, 辉锑矿原位S同位素组成、Cu、Pb之间明显的正相关性可能代表了热液成因的辉锑矿床成矿流体具岩浆来源的特征。
The Abunabu antimony deposit, located in the Yarlung-Zangbo suture zone, represents the first discovered antimony deposit in this area. By examining the mineralogy, in-situ trace elements and sulfur isotope composition of major sulfides such as pyrite, arsenopyrite and stibnite in the deposit, this paper explores the source and nature of mineralizing fluids to reveal its genesis. The antimony ore bodies are primarily hosted within intensely silicified gabbro, which serves as the main host rocks in the mining area. We categorize the deposit into a single hydrothermal metallogenic epoch which could be subdivided into the following four mineralization stages of the carbonate-sulfide stage, the coarse-grained quartz-sulfide stage, the quartz-stibnite stage and the fine-grained quartz-sulfide stage. Among them, the quartz-stibnite stage represents the principal mineralization stage. The LA-ICP-MS trace element analysis results of pyrite, arsenopyrite and stibnite reveal that characteristics of Co and Bi contents and δEu values in metal sulfides from various stages indicate that the ore-forming fluids in the Abunabu antimony deposit had relatively high temperatures during the formation of pyrite. As the fluid temperature gradually decreased, arsenopyrite and stibnite began to crystallize and precipitate. As mineralization progressed, the fluid environment transitioned from an initially weakly oxidizing state to a more strongly reducing environment, ultimately leading to the extensive precipitation of stibnite. The decrease in mineralizing fluid temperature and the transition from oxidizing to a strongly reducing environment are two critical mechanisms for the enrichment and precipitation of ore-forming elements. Additionally, the Abunabu antimony deposit is of hydrothermal origin, with mineralizing fluids derived from magmatic sources. The initial mineralizing fluids are characterized by significant enrichment in As and ore-forming element Sb, providing the material basis for mineralization. In stibnite, there exists a substitution mechanism of 2Sb^(3+)↔Cu^(+)+Pb^(2+)+As^(3+) among As, Cu and Pb. The in-situ sulfur isotope composition of stibnite and the significant positive correlation between Cu and Pb may indicate that the hydrothermal fluids responsible for the formation of the antimony deposit have characteristics indicative of magmatic origin.
作者
李保亮
王立强
高腾
何逸飞
何云龙
LI BaoLiang;WANG LiQiang;GAO Teng;HE YiFei;HE YunLong(MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resource,Chinese Academy of Geological Sciences,Beijing 100037,China;State Key Laboratory of Deep Earth and Mineral Exploration,Institute of Mineral Resource,Chinese Academy of Geological Sciences,Beijing 100037,China;School of Earth and Planetary Sciences,Chengdu University of Technology,Chengdu 610059,China;Zhaojin Mining Industry Company Limited,Zhaoyuan 265400,China)
出处
《岩石学报》
北大核心
2025年第5期1626-1643,共18页
Acta Petrologica Sinica
基金
国家重点研发计划青年科学家项目(2021YFC2900100)
中国地质调查局地质调查项目(DD20230203408、DD202402042)
中国地质科学院基本科研业务费专项(KK2306)联合资助。
关键词
原位微量元素
原位硫同位素
矿床成因
阿布纳布锑矿床
雅鲁藏布江缝合带
In situ trace elements
In-situ sulfur isotope
Genesis of deposit
Abunabu antimony deposit
Yarlung-Zangbo suture zone
