(1. 中南大学 有色金属成矿预测与地质环境监测教育部重点实验室，长沙 410083；
2. 中南大学 地球科学与信息物理学院，长沙 410083；
3. 湖南省湘南地质勘察院，郴州 423000)
摘 要: 湘南香花岭矿田是华南地区典型的岩浆热液型铟富集成矿区，新勘探的似层状锡矿体是矿田内重要的锡矿化类型，也是南岭地区较为独特的锡矿化类型，对该类矿体中铟的分布规律和富集机制缺乏系统研究。为揭示矿田内似层状锡多金属矿体中的铟富集特征及成因，在矿床野外地质调查及样品采集基础上，采用光学显微镜、等离子体光谱仪、电子探针等技术手段，开展了矿物组成显微鉴定、矿石化学成分分析、矿物微区成分分析等研究。结果表明：碎屑岩发育两类似层状锡矿体，即三合圩式以泥质碎屑岩为容岩的锡多金属矿体和泡金山式以石英砂岩为容岩的锡矿体。三合圩式矿体In含量12.94 μg/g~70.80 μg/g，Zn含量0.61%~2.62%，Sn含量0.13%~0.86%，为富铟的锡多金属矿体；泡金山式矿体In含量为0.04 μg/g~1.06 μg/g，Sn含量为0.06%~1.87%，为贫铟的锡矿体。载铟矿物有闪锌矿和黝锡矿，尤以闪锌矿最为重要。三合圩式矿体中闪锌矿的In含量最高为0.15%，泡金山式矿体中闪锌矿的In含量最高为0.19%，闪锌矿中元素替代关系为In2++Cd2+？2Cu2+。在三合圩式矿体中黝锡矿的In含量为0.25%，而在泡金山式矿体中黝锡矿的In含量低于检测限，黝锡矿中元素替代关系为In2++Zn2+？Cu2++Sn2+。综合矿床地质特征及铟富集研究，认为碎屑岩中似层状矿体成因与岩浆热液关系密切，两类矿体铟富集差异明显受成矿地质环境和成矿作用控制，在泥质砂岩中以交代为主的成矿作用形成了富铟的锡多金属矿体，而在石英砂岩中以充填为主的成矿作用则形成了贫铟的锡矿体。
关键字: 铟富集；矿物化学；成因；似层状锡多金属矿体；香花岭；湘南
（1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education, Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics Engineering, Central South University, Changsha 410083, China;
3. Southern Hunan Institute of Geology Survey, Chengzhou 423000, China）
Abstract:The Xianghualing orefield in southern Hunan, is a typical magmatic-hydrothermal type In mineralization area in South China. The newly explored stratoid Sn orebodies, showing an important Sn mineralization type in the orefield, are relatively unique type in the Nanling area. However, indium distribution and enrichment mechanism of these orebodies have not yet done enough research. In order to reveal the characteristics and genesis of In enrichment of the stratoid Sn polymetallic orebodies, ore mineral microscopic observation and identification, ore chemical composition analysis, and mineral microanalysis were carried out using optical microscope, plasma spectrometer, and electron probe based on geological surveys and sample collection of the orebodies. There are two types of stratoid Sn orebodies hosted by clastic rock: one is Sanhexu type, Sn polymetallic mineralition hosted by argillaceous clastic rock; the other is Paojinshan type, Sn mineralization hosted by quartz sandstone. The Sanhexu orebodies are In-rich Sn polymetallic orebodies with 12.94 μg/g-70.80 μg/g In, 0.61%-2.62% Zn, and 0.13%-0.86% Sn; while the Paojinshan orebodies are In-poor Sn orebodies with 0.04 μg/g-1.06 μg/g In, 0.06%-1.87% Sn. Indium-bearing minerals include sphalerite and stannite, especially sphalerite. Sphalerite contains In up to 0.15% in the Sanhexu orebodies, and that in the Sanhexu orebodies up to 0.19%. The element substitution mechanism of sphalerite is In2++Cd2+？2Cu2+. Stannite contains 0.25% In in the Sanhexu orebodies, but that in the Paojinshan orebodies is below detection limit. The element substitution mechanism of stannite is In2++Zn2+？Cu2++Sn2+. Based on geological characteristics of the deposit and research works of In enrichment, it is proposed that the stratoid orebodies hosted by clastic rocks are related to magmatic-hydrothermal, and the difference of In enrichment between two orebody types is controlled by geological environment and mineralization style. The metasomatic mineralization style in argillaceous sandstones forms In-rich tin polymetallic orebodies, while the filling mineralization style in quartz sandstones forms In-poor Sn orebodies.
Key words: indium enrichment; mineral chemistry; genesis; stratoid tin polymetallic orebodies; Xianghualing; Southern Hunan
