西藏甲玛铜多金属矿含矿斑岩石英斑晶单个熔融包裹体的成分研究

Composition of single melt inclusion in quartz phenocryst in the Jiama Cu-polymetallic Deposit,Tibet

研究甲玛铜多金属矿床岩浆结晶演化特点、岩浆热液过渡与矿化的关系。利用Linkam TS1500热台对甲玛矿床含矿斑岩石英斑晶中的熔融包裹体进行鉴定、均一温度测定,采用电子探针与同步辐射X射线荧光微探针对石英斑晶中的熔融包裹体进行常量元素及微量元素的测定,结果表明,含矿斑岩体形成温度为630~880℃。Na、Ca等元素易富集于岩浆挥发组分中,挥发组分饱和出溶形成高温、高盐度流体,成矿元素从最早的岩浆结晶分异阶段开始,强烈地选择性进入挥发性气相中进行迁移,出溶的挥发组分中具有成矿元素的初步富集。矿床在成因上与斑岩-夕卡岩成矿系统中的岩浆-热液成矿作用密切相关。

the relation of magmatic crystallization,evolution and hydrothermal transition to mineralization.Linkman TS1500 heating stage is used to characterize the melt inclusions in the quartz phenocryst of the ore-bearing porphyry in the Jiama Cu-polymetallic deposit and to measure their homogenization temperatures,while EMPA and SRXRF micro-probe are used to measure the major and trace elements of the melt inclusions.The formation temperature of the ore-bearing porphyry is 630~880℃.Na and Ca tend to be rich in magmatic volatile,and the volatile develops into hyperthermal and hypersaline fluids as it becomes saturated and exsolutioned.The metallogenic elements selectively force into the gas-phase of volatile from the earliest crystallization stage,and the metallogenic elements are preliminarily enriched in the exsolutioned volatile.A conclusion is arrived that the genesis of the deposit is closely related to magmatic hydrothermal mineralization in the porphyry-skarn system.