江西茅排金矿流体包裹体研究

流体包裹体的系统研究表明茅排金矿形成于中高温、中低压环境。从成矿早期至成矿晚期,成矿温度和压力、成矿流体的盐度、密度、Eh、pH、fo_2以及成分和氢氧同位素组成等具一定的演化规律。成矿流体主要来自岩浆热液,属H_2O-NaCl-CO_2(+CH_4)体系,富含CO_2、CH_4等挥发分。成矿晚期成矿流体出现不混溶性,有利于金的富集沉淀。流体包裹体中某些特征参数K~+/Na~+、CO_2/H_2O和含CO_2包裹体的丰度可作为金矿化贫富的判别标志。

FLUID INCLUSION STUDIES OF THE MAOPAI GOLD DEPOSIT, JIANGXI, CHINA

The quartz vein-hosted gold deposit at Maopai was controlled by both meta-migmatite complex and ductile shear zone. The gold mineralization can be divided into two stages, stage 1 and stage 2. Systematic studies of fluid inclusions from gold-bearing quartz veins indicate that the mineralization took place at intermediate temperature and pressure. revealing the evolution history of ore-formlng fluids from stage 1 to stage 2. The ore-forming fluids are rich in CO_2 and CH_4, and close to the H_2O-NaCl-CO_2 (+CH_4) system, providing evidence for a magmatie origin. It is also proposed that the gold deposition is related to the fluids rich in CO_2 and CH_4 and unmixing of fluids. Some specific parameters such as K~+/Na~+, CO_2/H_2O ratio and CO_2 enrichment in inclusions could be used as the indicators for prospecting.