云南麻栗坡祖母绿的流体包裹体研究

Fluid Inclusion Studies on Emeralds from Malipo Area,Yunnan Province,China

麻栗坡祖母绿产于老君山变质核杂岩内。作者对产于伟晶岩脉中祖母绿的流体包裹体进行了岩相学、显微测温和激光拉曼探针研究。研究表明,与成矿有关的流体为中-高温、低盐度的NaCl-H_2O-CO_2-CH_4±N_2体系。两相H_2O-NaCl型包裹体与H_2O-NaCl-CO_2型包裹体密切共生,两者均一温度范围较一致且后者盐度相对较低。麻栗坡祖母绿包裹体特征表明,流体不混溶作用是麻栗坡祖母绿矿物形成的主要机制。麻栗坡祖母绿矿床的形成与侵入岩有关。

Malipo emerald originates in Laojunshan metamorphic core complex. Petrographic observation, microthermometry and Raman spectroscopy studies on fluid inclusions in emerald from pegmatite vein were conducted. Results show that the mineralization was related to mesothermal- hypothermal fluid of NaC1-H20-CO2-CH4 ± N2 system with low salinities. There are paragenetic relationship in two-phase H20-NaC1 type fluid inclusions and H20-NaC1-CO2 type inclusions, and the main homogenization temperature ranges of the two types inclusions approximate each other, while the salinity of H20-NaCl-CO2 type inclusions is lower than that of H2O-NaCl type inclusions. Characteristics of fluid inclusions in emerald show that the precipitation of emerald is due to fluid immiscibility. The genesis of Malipo emerald deposit is believed to be related to the intrusive rock.