中国典型脉型钨、锡矿床和斑岩钼矿流体包裹体特征

Characteristics of Fluid Inclusion for Typical Tungsten,Stannary Vein Deposit and Porphyry Molybdenum Deposit in China

中国脉型钨、锡矿床和斑岩钼矿无论在时空分布上还是在成矿特征上都有很大的相似性。本文以几个典型矿床为例,从流体包裹体角度对比分析了其成矿特征的异同。根据流体包裹体的组合类型、气液比等特征可以大致推断出成矿温度。流体成分与岩浆的侵入深度之间存在着近似相关关系。随着成矿过程的进行,流体温度和盐度逐渐降低,钨、锡流体特征非常相似,但锡矿床的盐度略高于钨矿床。斑岩钼矿的盐度非常高,这是典型的次火山体系的流体特征,压力影响着成矿温度及流体成分。流体成分上锡矿床CO2含量明显要高于钨矿床,而且F的含量较高,斑岩钼矿床由于其源区物质成分的差异导致流体具有不同的特征。流体沸腾、混合及自然冷却是流体演化的3个过程,其中流体沸腾对成矿意义重大。CO2是挥发份中的常见组分,能影响流体不混溶的发生条件。

There are great similarities for tungsten vein deposit,Sn vein deposit and porphyry molybdenum deposit in China,in the spatial and temporal distribution or metallogenic characteristics.Through the analysis of metallogenic characteristics from fluid inclusions,comparison is made among several classical deposits about their formation similarities and differences.The ore-forming temperature can be approximately concluded by means of the type of fluid inclusions and the ratio of gas and liquid.The composition of fluid and the depth of magmatic intrusion has a close relationship.With the evolution of mineralization,the fluid of temperature and salinity gradually decrease,and so do the features of the tin fluid and the tungsten fluid.But the salinity of stannary vein deposit is a slightly highter than that of tungsten vein deposit.The salinity of porphyry molybdenum deposit is remarkable high,which is the fluid features of the typical subvolcanic system,because the temperature and composition of fluid are affected by pressure.Among the three significant processes in fluid evolution（boiling,mixing and natural cooling）,boiling is more important for the mineralization.CO2 is a common volatile flux,and plays a fundamental role in the boiling.