| 羊拉地区含矿夕卡岩流体包裹体特征及其成因意义带 |
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| 引用本文：.1998.Fluid inclusions in ore-bearing skarns from the Yangla copper mineralization concentrated area of Deqen County, Yunnan Province[J].Mineral Deposits,17(4):331~342 |
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| 基金项目:地质矿产部定向基金（地科定95-12）和九五资源与环境攻关项目（95-02-001-03） |
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| 中文摘要:羊拉铜矿化集共有4个夕卡岩体，按成因分为喷流-沉积和接触交代夕卡岩两大类，前者呈层状，是铜的主要赋矿围岩。层状夕卡岩中包裹体以类型多、组分复杂、均一温度（100～620℃，一般大于300℃）和盐度（8.3%～55.0% NaCl，一般≥20% NaCl）高且变化范围大、密度高(一般大于1.00 g／cm3)、捕获压力低 (10～20 MPa)为特征；交代夕卡岩则以包裹体类型简单、组分单一、均一温度（一般小于250℃）和盐度中-低（9.0%～20.0% NaCl)、密度低（一般小于1.00 g/cm3）且变化范围大、捕获压力高 (150 MPa)为特征。这些包裹体特征反映了两类夕卡岩的流体来源和演化机制是不同的，其中层状夕卡岩之流体为深部源与海水源的二元混合特征；交代夕卡岩为岩浆（体）源等组分自然冷却演化趋势。 |
| 中文关键词:喷流-沉积作用，接触交代作用，矽卡岩铜矿，流体包裹体，云南羊拉 |
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| Fluid inclusions in ore-bearing skarns from the Yangla copper mineralization concentrated area of Deqen County, Yunnan Province |
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| Abstract:The Yangla copper mineralization concontrated area is located in Deqen County, northwestern Yunnan and tectonically belongs to Jinshajiang suture belt. There are four skarn bodies named Linong stratiform skarn (SKl), Lunong skarn (SK2), Linong granodiorite-hosted skarn (SK3) and Beiwu skarn (SK4) respectively, which are genetically grouped into two types, viz., exhalative skarn (including SKl and SK2) and contact metasomatie skarn (incluiding SK3 and SK4). The exhalative skarn is stratiform and serves as the most important host rock of copper deposits in this area. There are five types of inclusions in such transparent minerals as garnet, diopside, quartz and calcite within the stratiform skarns. They are monophase liquid inclusions (L), liquid-rich two phase gas-liquid ories (LV) , gas-rich-a two-phase gas-liquid ones (VL), CO2-bearing ones (C) and polyphase ones that contain daughter crystal halite (S). The fluid systems in these inclusions are complex and variable and their homogenization temperatures and salinities arc high and vary in wide ranges of 100～620℃, generally >300℃, and 8.3%～55.0 % NaCl equaivlent, commonly>20wt % respectively. The temperatures show a positive correlation with the salinities. The densities of most fluid inclusions are higher than l.00 g/cm3. The trapping pressures for inclusions are relatively low (10～25 MPa). The inclusions in the contact metasornatic skarn are mainly of L and LV types, with a small proportion belonging to C type. The fluid systems are simple: the homogenizatiori temperatures, salinities and densities arc relatively low, generally <250℃, <20.0% NaCl equivalent and ≤1.00 g／cm3 respectively, and the salinities are almost constant when the temperature decreases to 100℃. Their minimum trapping pressure is as high as 150 MPa. Comparative studies are made on the inclusions in quartz vein (Qv) from SKl. There exist similarities of inclusions in Qv to those in SK3 in such aspects as homogenization temperatures, salinities, densities and relationship between temperature and salinity. The secondary inclusions in all samples are measured. The observed varizations in temperature, salinity, density etc. suggest that the fluids for stratiform skarns were derived from two sources, namely hot saline solution and cool, less saline seawater, whose mixing mechanism is reasonably attributed to exhalative-sedimentation. Fluids for contact-metasomatic skarns came from granodiorite magma. The systematic inclusion data also indicate that there occurred at least three structural-thermal events in the Yangla mineralization concentrated area. |
| keywords:exhalative-sedimentation, contact-metasomatism, skarn copper skarn deposit, fluid inclusion, Yunnan |
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