(1. 中南大學 有色金屬成礦預測與地質(zhì)環(huán)境監(jiān)測教育部重點實驗室，長沙 410083；
2. 中南大學 地球科學與信息物理學院，長沙 410083；
3. 湖南省湘南地質(zhì)勘察院，郴州 423000)
摘 要: 湘南香花嶺礦田是華南地區(qū)典型的巖漿熱液型銦富集成礦區(qū)，新勘探的似層狀錫礦體是礦田內(nèi)重要的錫礦化類型，也是南嶺地區(qū)較為獨特的錫礦化類型，對該類礦體中銦的分布規(guī)律和富集機制缺乏系統(tǒng)研究。為揭示礦田內(nèi)似層狀錫多金屬礦體中的銦富集特征及成因，在礦床野外地質(zhì)調(diào)查及樣品采集基礎上，采用光學顯微鏡、等離子體光譜儀、電子探針等技術(shù)手段，開展了礦物組成顯微鑒定、礦石化學成分分析、礦物微區(qū)成分分析等研究。結(jié)果表明：碎屑巖發(fā)育兩類似層狀錫礦體，即三合圩式以泥質(zhì)碎屑巖為容巖的錫多金屬礦體和泡金山式以石英砂巖為容巖的錫礦體。三合圩式礦體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%，為富銦的錫多金屬礦體；泡金山式礦體In含量為0.04 μg/g~1.06 μg/g，Sn含量為0.06%~1.87%，為貧銦的錫礦體。載銦礦物有閃鋅礦和黝錫礦，尤以閃鋅礦最為重要。三合圩式礦體中閃鋅礦的In含量最高為0.15%，泡金山式礦體中閃鋅礦的In含量最高為0.19%，閃鋅礦中元素替代關系為In2++Cd2+？2Cu2+。在三合圩式礦體中黝錫礦的In含量為0.25%，而在泡金山式礦體中黝錫礦的In含量低于檢測限，黝錫礦中元素替代關系為In2++Zn2+？Cu2++Sn2+。綜合礦床地質(zhì)特征及銦富集研究，認為碎屑巖中似層狀礦體成因與巖漿熱液關系密切，兩類礦體銦富集差異明顯受成礦地質(zhì)環(huán)境和成礦作用控制，在泥質(zhì)砂巖中以交代為主的成礦作用形成了富銦的錫多金屬礦體，而在石英砂巖中以充填為主的成礦作用則形成了貧銦的錫礦體。
關鍵字: 銦富集；礦物化學；成因；似層狀錫多金屬礦體；香花嶺；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
