西藏甲玛铜多金属矿三期石榴子石地球化学特征及成矿意义  

Geochemical characteristics and metallogenic significances of the three garnets in Jiama Cu-polymetallic Deposit,Tibet

作　　者：秦志鹏[1] 唐晓倩[1] 周云[1] 宋磊[1] 

机构地区：[1]成都理工大学地球科学学院,成都610059

出　　处：《有色金属（矿山部分）》2013年第2期22-26,共5页NONFERROUS METALS(Mining Section）

基　　金：西藏甲玛斑岩铜多金属矿科学基地协作研究基础研究课题(200911007-02);国家重点基础研究计划(973计划)项目(2011CB403103);国土资源地质大调查项目(1212010012005)

摘　　要：研究西藏甲玛铜多金属矿三期岩浆成因石榴子石的地球化学特征及成矿指示意义。通过分析三期岩浆成因的石榴子石内侧带、中间带和边缘带样品的矿物地球化学特征,得出以下结论:三期石榴子石均为钙质系列,距岩体越远,钙铝榴石成分含量越高;石榴子石的稀土总量较低,均显示正Eu异常的轻稀土富集型右倾配分模式;形成石榴子石的流体均具有铜多金属成矿潜力,由内向外显示由Cu、Au向W、Pb、Zn的演化趋势;流体温度和氧逸度不仅控制了钙铁榴石—钙铝榴石的分馏,更是矿质沉淀的内因。在甲玛矿床,钙铁榴石与钙铝榴石的比值可以作为成矿作用的一个指示性标志。The geochemical characteristics and metallogenic significance of the three magmatic related garnets from Jiama Cu-polymetallic Deposit are studied. By analyzing their geochemical characteristics from the inner, intermediate and marginal, zone, we concluded that the three garnets are all calcareous series, and the farther away from the porphyries, the grossular contents will be higher. Total contents of the REEs which characterized by a steeplyrising slope from the LREE to the HREE with positive Ce-anomaly and positive Eu-anomaly are relatively low. The garnet fluids express Cu-polymetallic mineralization potential and show the evolution trends of the inside Cu, Au to the outside W, Pb, Zn. The fluid temperature and oxygen fugacity not only control the andradite grossular fraction ation, but also are the reasons of the mineral precipitation. In Jiama Deposit, the ratios between andradite and grossular can he used as an indicative signs of mineralization.

关 键 词：石榴子石 地球化学 成矿意义 甲玛 西藏 

分 类 号：P595[天文地球—地球化学]