四川耳泽金矿床成矿流体不混溶的流体包裹体证据

Liquid Inclusion Evidence of Mineral Liquid Immisicibility of Sichuan Erze Gold Deposit

木里耳泽金矿床矿体位于上二叠统岗达概组,矿体形态受断裂构造和层间破碎带控制,大多数呈透镜状或脉状。成矿阶段划分为菱铁矿阶段与石英—硫化物—金阶段。矿床中流体包裹体类型分为H_2O包裹体、CO_2包裹体、H_2O-CO_2包裹体,主要分布于石英—硫化物—金阶段。本文主要运用包裹体均一测温法探讨了成矿流体不混溶的热力学条件。H_2O包裹体均一温度为124.6℃247.6℃,盐度为5.86%3.06%。H_2O-CO_2包裹体的完全均一温度为179.6℃296.6℃,部分均一温度为15.6℃30.6℃,水合物最后融化温度范围为7.5℃9.1℃,相应的盐度约为1.83%4.87%。计算的成矿压力为1 010 bar。测试过程中,富H_2O相的H_2O-CO_2包裹体和富CO_2相的H_2O-CO_2包裹体的完全均一温度和压力非常接近,可以证明它们是同一时期捕获的CO_2与NaCl-H_2O不混溶流体包裹体组合。

Erze gold deposit is located in Dgai formation of upper Permian,the orebody is controlled by fault structure and interlayer fracture zone,most of them are lenticular and vein. The metallogenic stage can be divided into siderite stage and quartz-sulfide-gold stage. The liquid inclusion types in the deposit include H2 O inclusion,CO2 inclusion,H2 O-CO2 inclusion,mainly in the stage of quartz-sulfide-gold stage. In this paper,the thermodynamics condition of immiscible mineral liquid is discussed by homogeneous temperature measurement. The homogenization temperature of H2 O inclusion is 124. 6℃ to 247. 6℃,and salinity is 5. 86% to3. 06%. The average homogenization temperature of H2 O-CO2 inclusion is 179. 6℃ to 296. 6℃,the partial homogenization temperature is 15. 6℃ to 30. 6℃,the final melting temperature range of hydrate is 7. 5℃ to9. 1℃,the corresponding salinity is about 1. 83% to 4. 87%. The calculated ore-forming pressure is1010 bar. During the test,the H2 O-CO2 inclusion in the H2 O rich phase and CO2 rich H2 O-CO2 inclusio nare very close to the homogeneous temperature and pressure,it＇s proved that they are captured in the same period as CO2 and NaCl-H2 O immiscible fluid inclusion combination.