山东谢家沟金矿流体包裹体研究及其地质意义

山东谢家沟金矿是新发现的产于玲珑型花岗岩中的蚀变岩型金矿。对3个成矿阶段含矿流体的温度、压力和成分分析表明，矿床属于浅成中温热液矿床。含矿流体的演化是从高温向低温、从低盐度、低密度向高盐度、高密度的转变。Ⅰ成矿阶段流体包裹体均一温度为320~350 ℃，盐度为2.7%~6.6%，密度为0.498~0.886 g/cm³；Ⅱ成矿阶段包裹体均一温度为270~330 ℃，盐度为3.6%~8.4%，密度为0.571~0.959 g/cm³；Ⅲ成矿阶段包裹体均一温度为250~290 ℃，盐度为5.8%~10.6%，密度为0.724~1.158 g/cm³。流体成分以CO₂和H₂O为主，尚有CO、CH₄、H₂S、SO₂、N₂等，流体中CO2含量与矿石金品位正相关。据不同类型包裹体共生组合及流体演化特征，认为流体的不混溶性是导致大量金沉淀的主要原因。

Study on the Fluid Inclusions from Xiejiagou Gold Deposit in Shandong and Its Geological Significance

Xiejiagou gold deposit is a newly found alteration deposit which occurred in Linglong granite at the Jiaodong area, Shandong By analyzing the temperature, pressure and the component of the fluid inclusions in three mineralization stages, it is included that this gold deposit is an epithermal deposit and the gold bearing fluid is salt water solution In the first mineralization stage, the homogenous temperature of fluid inclusions ranged from 320 ℃ to 350 ℃, with salinity from 2 7% to 6 6% NaCl equivalent and density from 0 498 g/cm 3 to 0 886 g/cm 3 ; in the second mineralization stage, the homogenous temperature of fluid inclusions ranged from 270 ℃ to 330 ℃, with salinity from 3 6% to 8 4% NaCl equivalent and density from 0 571 g/cm 3 to 0 959 g/cm 3 ; in the last mineralization, the homogenous temperature of fluid inclusions ranged from 250 ℃ to 290 ℃, with salinity from 5 8% to 10 6% NaCl equivalent and density from 0 724 g/cm 3 to 1 158 g/cm 3 So the evolution of gold bearing fluid was a process that temperature decreased and salinity and density increased CO 2 and H 2 O are the main components of the fluid, with CO, CH 4 , H 2 S, SO 2 and N 2 involved There are some positive relationships between the content of CO 2 in the fluid and the grade of gold in the ores The assemblage of different fluid inclusions and the evolution of fluid show that immiscibility is the key element for mineralization