普朗斑岩铜矿岩浆混合作用：岩石学及元素地球化学证据  

Magma Mixing in the Pulang Porphyry Copper Deposit:Evidence from Petrology and Element Geochemistry

作　　者：曹殿华[1] 王安建[1] 李文昌 王高尚[1] 李瑞萍[1] 李以科[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]云南省地质调查局,昆明650051

出　　处：《地质学报》2009年第2期166-175,共10页Acta Geologica Sinica

基　　金：中央级公益性科研院所基本科研业务费专项资金(编号K2007-1-1);国家科技攻关计划课题(编号2001BA609A-05,2003BA612A-05);国家973课题(编号2002CB412607);国家科技支撑计划课题(编号2006BAB01A07,2006BAB01B05);地质调查项目(编号121201066307)资助的成果

摘　　要：普朗斑岩铜矿花岗闪长斑岩中存在大量的随机分布的镁铁质微粒包体,包体与寄主岩存在渐变接触关系。包体成分为闪长质,具有岩浆结构,存在针状磷灰石,显示了快速冷却结晶的特征。包体内可见具有暗色矿物镶边的眼球状石英,表明存在岩浆混合作用。元素地球化学特征显示包体与寄主岩之间有成分交换。包体和寄主岩强不相容元素均富集,高场强元素Nb、Ta、Ti均表现出显著的负异常,具有典型的岛弧岩浆岩的微量元素特征,包体和寄主岩Mg#均较高,源区均有幔源岩浆的贡献。普朗斑岩铜矿蚀变矿化模式反映了其成矿环境偏基性,暗示镁铁质岩浆的加入对成矿具有贡献。Plenty of mafic microgranular enclaves exist at random in granodiorite porphyrite at the Pulang porphyry copper deposit, and the enclaves gradually contact with host rocks. The enclaves consist mainly of diorite and are of magmatic texture. Presence of speculate apatites indicates quick cooling crystallization of the magma. The mafic-rimmed quartz ocelli in the enclaves suggest the existence of magma mixing. The geochemisty features suggest occurrence of exchange of elements between enclaves and host rock. Both enclaves and host rocks are enriched in LILEs and LREEs and depleted in HFSEs, and show distinct negative anomalies in Nb, Ta and Ti, indicating that the both magma are of typical trace elment characteristic of the island arc setting. The enclaves and host rocks contain high content of Mg^# and K, which strongly suggests a eontrtibution of mantle-derived magma. The altered mineralization model of the Pulang porphyry copper deposit reflects a basic metallogenic environment, implying a contribution of marie magma to the formation of porphyry copper mineralization.

关 键 词：普朗 斑岩铜矿 镁铁质微粒包体 岩浆混合作用 

分 类 号：P618.41[天文地球—矿床学]