粤西罗定盆地南缘金矿地球化学特征及成矿作用

Geochemical characteristics and metallogenesis of gold deposits in southern margin of Luoding basin,western Guangdong Province

研究区矿石及近矿蚀变围岩中黄铁矿的硫、铅同位素组成特征,以及金矿石(含金石英脉)和花岗斑岩的稀土元素特征,显示金矿成矿物质来源于地壳。矿体石英中的流体包裹体氢、氧同位素组成特征,显示成矿热液来源于大气降水。结合气液包裹体均一温度,认为本区金矿的成矿作用发生于低温、浅成-超浅成的环境条件,金矿的成因类型为浅成-超浅成低温热液型。

According to sulphur and lead isotopic compositions of pyrites from ores and adjoining altered rocks and REE characteristics of gold veins and granite porphyries,the metallogenetic elements should come from the crust. Oxygen and hydrogen isotopic compositions of fluid inclusions within quartz from the gold veins suggest that the ore-forming fluid came from meteoric water. Considering the low homogenization temperature of gas-liquid inclusions,the gold deposits in the southern margin of the Luoding basin were formed under a low-temperature supergene depth,belonging to a kind of epithermal gold deposits.