滇西马厂箐铜钼(金)矿床是与喜马拉雅期富碱侵入岩体有成因联系的内生金属矿床。铜钼金成矿与马厂箐岩体空间上紧密相伴,时间上相近或稍晚。蚀变矿化和元素组合具有明显地分带性:岩体内发育斑岩型铜钼矿化,岩体与围岩接触带产出接触交代型铜钼(金)矿化,围岩地层中则产出浅成低温热液型金、银、铅锌矿化。铜钼矿化主要发育在石英钾长石绢云母化蚀变带中。这些不同成矿作用在时空上紧密共生,在矿化类型、蚀变类型和元素组合分布上连续递变,清晰地展现出成矿流体从岩浆中分凝出来并在向外运移的路径上淀积金属的图像。同位素地球化学研究表明,喜马拉雅期富碱侵入岩提供了成矿物质和成矿流体,铜钼金成矿属于同一个构造-岩浆-成矿系统在不同物理化学条件下的产物。受富碱侵入伴驱动,成矿作用由斑岩体内部向接触带和围岩地层推进,矿化类型、围岩蚀变和元素组合反映出成矿流体系统由高温向低温的演化趋势。
Machangqing Cu-Mo-Au deposit is one of the deposits which have a close genetic relation with Himalayan alkaline intrusive in western Yunnan Province. The Cu-Mo-Au mineralization is spatially and temporally accompanied with the Machangqing intrusive. There are distinct zonations of alteration,mineralization and the element assemblages:porphyry-type Cu-Mo mineralization inside the intrusive,contact-metasomatic-type Cu-Mo-Au mineralization along the contact between the intrusive and surrounding rock,epithermal Au-Ag-Pb-Zn mineralization in wallrock,and Cu-Mo mineralization mainly in the alteration zone of quartz-K-feldspar-sericite of intrusive. The spatial and temporal relationship of metallogeny,the types of mineralization and alteration,and the distribution of element association display that ore-forming fluid deriving from magma crystallization accumulated along the path while migrating outward. Isotopic geochemistry research shows that Cu-Mo-Au deposits may be the products of the same magmatic-tectonic metallogenic system under different physical-chemical conditions. Alkaline intrusive rock in Himalayan provided ore-forming material and fluid,and the thermal dynamic condition for deposit formation,which is reflected by the alteration change from the interior of porphyry mass to contact zone and country rock. The types of mineralizatin,alteration of the country rock,as well as element assemblage indicate the evolution process from high temperature to low temperature suggesting an indispensable result of magmatic evolution.