老挝班康姆铜金矿床成矿条件及成矿机理研究

摘要

班康姆铜金矿床是近年来发现的大型铜金矿床,矿体主要赋存于中基性火山岩之中,其微量元素特征、玄武岩类的Ti-Zr-Y、Ti-Zr判别图、花岗岩类在Nb-Y(A)、Rb-(Y+Ta)判别图均表明成矿构造环境为岛弧环境,火山岩属于中钾钙碱性系列.岩浆岩稀土总量较低,标准化模式曲线均为略富集轻稀土的平坦型,Eu几乎不存在异常,说明火山岩、侵入岩为同源不同期的产物,岩浆热液来源于地幔或下地壳,热液活动划分为火山喷发期、热液叠加期,其成矿物质来源于安山岩,矿(化)体受NNE断裂构造、岩浆岩控制,矿床类型为与岩浆岩密切相关的复合型热液矿床.%Pangkuam Cu-Au deposit is a large Cu-Au deposit discovered in recent years in Laos.The orebodies occur mainly in basic volcano rocks.The Tectonic setting is an island arc environment inferred by trace ele-ment characteristics,Ti-Zr-Y,Ti-Zr discrimination diagrams of basalts,Nb-Y(A)and Rb-(Y+ Ta)discrimi-nation diagrams of granitoids.Volcanic rock is belonged to potassium calc-alkaline series.The REE content of magmatic rock is lower,standardized pattern curves are flattened type with light rare earth elements slightly enriched,and there are almost not Eu anomaly at all.It is indicated that volcanic rocks and intrusive rocks are the product of homologous source in different stages,and that magmatic hydrothermal fluid is de-rived from the mantle or the lower crust.Hydrothermal activity is divided into volcanic eruption period,hy-drothermal superimposition.As mineral material derived from andesite,the orebody is controlled by NNE faults and magmatic rock.The deposit type is considered to be complex hydrothermal deposit which is close-ly associated with magmatic rocks.