云南西盟阿莫锡矿成矿物质来源

通过对氧、硫同位素组成、矿物包裹体均一温度的测定,以及稀土配分型式、花岗岩中Sn含量增减变化的分析结果表明,西盟阿莫锡矿成矿物质主要来源于下伏的隐伏花岗岩岩体及围岩中———永龙组下段片岩及大黑山组上段变粒岩。花岗岩浆期后的含矿流体沿断裂迁移、充填、交代,在此过程中,由于压力锐减,发生流体沸腾,气液分离,酸碱分异,锡石沉淀;随着温度的下降,流体化学性质转化,出现不同蚀变和不同矿物组合的多个成矿阶段,而不同断裂类型,又控制着矿体的形态和规模。

Source of ore-forming matter in the Ximeng Amo tin deposit in Yunnan

Based on the data of the isotopic competition of Oxygen and Sulphur,the homogenetic temperature of the mineral inclusions,REE partitioning model,Sn content of granite increase or decrease,it is suggested that metallogenic material in Ximeng Ameau mainly derived from the underlying buried Granite mass and surrounding rock(Schists of Ximeng group and granulite of big black hills group of Yonglong group).Ore bearing fluid from granitic period transports,fills and replaces along the fault,in this process,because of the pressure which fall sharply,fluid boiling,gas-fluid separation,acidity and alkali differentiation,cassiterite sedimentation.As the temperature drops,fluid chemical properties conversed,appearing multiple mineralization stages of different alteration and mineral association,while different fracture types control the morphology and size of orebody.