| 滇东南老君山南秧田钨矿床的成矿流体和成矿作用 |
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| 引用本文：冯佳睿,毛景文,裴荣富,李超.2011.Ore-forming fluids and metallogenesis of Nanyangtian tungsten deposit in Laojunshan, southeastern Yunnan Province[J].Mineral Deposits,30(3):403~419 |
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| 基金项目:本文得到中央级公益性科研院所基本科研业务费专项资金（编号：K0922）和国家自然科学重点基金（编号：40930419）的联合资助 |
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| 中文摘要:南秧田钨矿床位于滇东南老君山钨锡多金属成矿区。矿体形态简单，主要呈层状和似层状，在空间上与矽卡岩密切相关。该矿床的形成经历了矽卡岩期和石英硫化物期，前者可分为矽卡岩阶段和退化蚀变阶段，后者可分为石英硫化物阶段和方解石硫化物阶段。白钨矿主要形成于退化蚀变阶段。文章对南秧田矽卡岩型钨矿床内不同成矿阶段的石榴子石、绿帘石、石英、萤石和方解石中的流体包裹体进行了岩相学特征、显微测温、激光拉曼光谱分析等研究。结果表明，该矿床内的流体包裹体主要有3种类型：富液相包裹体、富气相包裹体和含子矿物多相包裹体。流体包裹体的气相成分以H2O、CH4和N2为主，含少量CO2，液相成分以H2O为主。矽卡岩期流体包裹体的均一温度为260～420℃，盐度w(NaCleq)为6.45%～53.26%，流体密度为0.83～1.15 g/cm3。石英硫化物期流体包裹体的均一温度主要集中于160～300℃，w(NaCleq)为4%～8%，流体密度为0.67～0.96 g/cm3，与矽卡岩期相比，温度、盐度和密度明显降低。石榴子石、石英和方解石的δ18OSMOW值为3.78‰～16.23‰，δ18OH2O值为4.52‰～10.28‰，δD值为-83‰～-59‰，表明成矿流体主要是岩浆水。黄铁矿的δ34S值为4.2‰～8.1‰，反映出深部岩浆硫的来源特征。南秧田钨矿床的成矿时代为晚三叠世，其形成可能与印支期岩浆作用有关。 |
| 中文关键词:地球化学 钨矿床 矽卡岩 流体包裹体 氢、氧、硫同位素 成矿作用 南秧田 滇东南 |
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| Ore-forming fluids and metallogenesis of Nanyangtian tungsten deposit in Laojunshan, southeastern Yunnan Province |
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| Abstract:The Nanyangtian tungsten deposit is located in the tungsten-tin polymetallic ore-forming area in Laojunshan, southeastern Yunnan Province. Ore bodies, fairly simple in shape, are largely concordant with the bedding of the strata, and the distribution of the ore bodies is spatially related to skarn. The formation of tungsten deposit experienced a period composed of skarn phase and quartz sulfide phase. The skarn phase is divided into skarn stage and retrogressive alteration stage, whereas the quartz sulfide phase consists of two stages called respectively quartz-sulfide stage and calcite-sulfide stage. Tungsten mineralization probably occurred at the retrogressive alteration stage. There are three dominant types of fluid inclusions, as evidenced by petrographic characteristics of fluid inclusions of garnet, epidote, quartz, fluorite and calcite formed at different ore-forming stages in the Nanyangtian tungsten deposit; they are liquid-rich inclusions, gas-rich two-phase inclusions and daughter-minerals bearing polyphase inclusions. Systemmatic measurement of homogeneous and freezing temperatures as well as salinities and laser Raman spectroscopic analysis of fluid inclusions were conducted. The gas compositions of ore-forming fluids in the Nanyangtian tungsten deposit are mostly H2O, CH4 and N2, with a small amount of CO2, whereas the liquid composition is primarily H2O. Fluid inclusions in the skarn phase show homogenization temperatures and salinities〔w(NaCleq)〕 from 260℃ to 420℃ and from 6.45% to 53.26% respectively, with the densities ranging from 0.83 g/cm3 to 1.15 g/cm3 Homogenization temperatures and salinities 〔w(NaCleq)〕 of fluid inclusions in the quartz-sulfide phase mainly vary from 160℃ to 300℃ and from 4% to 8% respectively, and the densities of the fluids are 0.67～0.96 g/cm3, which are obviously lower than the data of the fluid inclusions in the skarn phase The δ18OSMOW values of garnet, quartz and calcite range from 3.78‰ to 16.23‰, with the corresponding δ18OH2O values between 4.52‰ and 10.28‰, and δD values of fluid inclusions between -83‰ and -59‰ The combined isotopic data imply that the ore-forming fluids in the Nanyangtian tungsten deposit were mainly derived from magmatic fluids. The δ34S values of pyrite from the Nanyangtian tungsten deposit vary in a narrow range of 4.2‰～8.1‰, reflecting the derivation of sulfur from deep magma source. Tungsten mineralization in the Nanyangtian ore deposit took place in Late Triassic, with its metallogenesis related to the magmatic activity during the Indosinian period. |
| keywords:geochemistry, tungsten deposit, skarn, fluid inclusion, oxygen-hydrogen-sulfur stable isotopes, metallogenesis, Nanyangtian, Southeastern Yunnan |
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