| 湘南荷花坪锡多金属矿床流体包裹体研究 |
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| 引用本文：蔡明海,余存林,王显彬,刘虎,郭腾飞,彭振安.2013.湘南荷花坪锡多金属矿床流体包裹体研究[J].地球学报,34(6):654-664. |
| DOI：10.3975/cagsb.2013.06.02 |
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| 基金项目:国家自然科学基金项目(编号: 40972073) |
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| 中文摘要:荷花坪锡多金属矿床是湘南地区新发现的一大型矿床, 主要由印支期矽卡岩型矿石和燕山期蚀变碎裂岩型矿石所组成, 且以前者为主体。本文在详细的野外调查和岩相学观察基础上, 将区内印支期成矿分为三个成矿阶段(I-含锡矽卡岩阶段; II-硫化物阶段; III-石英-方解石阶段), 燕山期成矿分为两个阶段(I-锡石-硫化物阶段; II-方解石阶段)。对不同期石英、绿柱石、方解石等矿物中流体包裹体的研究表明, 荷花坪矿床包裹体类型主要为H2O-NaCl型、H2O-NaCl-CO2型和少量纯CO2型。显微实验结果显示, 印支期成矿流体主要为低盐度(ω(NaCleq)=3%~10%)的H2O-NaCl和H2O-NaCl-CO2以及少量富CO2流体。三个成矿阶段的完全均一温度分别为290~390℃、190~260℃和140~180℃。成矿早阶段流体中含较多CO2, 晚阶段CO2含量减少, 主要为H2O-NaCl, 且Ca2+、Mg2+含量增高。燕山期成矿流体亦为低盐度(ω(NaCleq)=2%~10%)H2O-NaCl和H2O-NaCl-CO2, 二个成矿阶段的完全均一温度分别为190~340℃和130~170℃, 成矿早阶段流体中含较多CO2, 晚阶段CO2含量减少, 主要为NaCl-H2O。两期成矿从早到晚都呈现出盐度降低、密度增大的变化趋势。区内成矿流体主要来自岩浆和地下水热液, 成矿早阶段以岩浆流体为主, 晚阶段以地下水为主。区内锡成矿主要与含CO2的流体以及流体的沸腾作用有关, 铅锌矿化主要与盐-H2O溶液流体作用关系密切。 |
| 中文关键词:地球化学 流体包裹体 成矿作用 荷花坪锡多金属矿床 湘南地区 |
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| Fliud Inclusion Study of the Hehuaping Tin-polymetallic Deposit in Southern Hunan Province |
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| Abstract:The Hehuaping tin-polymetallic deposit is a large-size tin-polymetallic orefield newly discovered in southern Hunan Province. It consists of Indosinian skarn-type ores and Yanshanian altered-cataclastite-type ores. Four ore bodies have been explored, which are located in the southeast portion of the Wangxianling Indosinian granite pluton and hosted in granite, granite porphyry, and Devonian limestone, dolomitite and sandstone, respectively. Based on detailed field investigation and petrographic observation, the authors carried out microthermometric studies of fluid inclusions in quartz, berylite and calcite in different types of ores. Three stages of Indosinian skarn-type ores have been distinguished, i.e., Stage I–cassiterite and skarn stage, StageⅡ–sulfide stage, and Stage Ⅲ–quartz and calcite stage. Fluid inclusions in the skarn-type ores can be divided into three types: H2O-NaCl type, H2O-NaCl-CO2 type, and minor pure CO2 type. Experimental results show that the homogenization temperatures are from 290℃ to 390℃, from 190℃ to 260℃ and from 140℃ to 180℃ for Stage I, II and III, respectively. The fluid inclusions at Stage I are enriched in CO2, whereas those at the late stage (Stage II, Stage III) are enriched in NaCl-H2O, with minor amounts of Ca2+, Mg2+ ions. In addition, the two major stages of Yanshanian altered cataclastite-type ores have been distinguished: Stage I—cassiterite-sulfide stage, and Stage II—calcite stage. Yanshanian fluid inclusions can be divided into H2O-NaCl type and H2O-NaCl-CO2 type. The homogenization temperatures are from 190℃ to 340℃ and from 130℃ to 170℃ for Stage I and II, respectively. The composition of the fluid inclusions at Stage I are enriched in CO2, whereas those at Stage II are enriched in NaCl-H2O. The characteristics of fluid inclusions in the Hehuaping deposit indicate that the fluid was derived from granites and groundwater. At the early stage the fluid was mainly magmatic fluid, but at later stages the fluid was dominated by groundwater. The fluid that was enriched in CO2 and the fluid that boiled at the early stage possibly led to cassiterite precipitation, and the mineralization of lead and zinc was related to NaCl-H2O fluid. |
| keywords:geochemistry fluid inclusion mineralization Hehuaping tin-polymetallic deposit southern Hunan |
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