西藏甲玛铜多金属矿床岩浆混合作用及对成矿的贡献  

The role of magma mingling in mineralization of the Jiama copper-polymetallic deposit in Tibet

作　　者：苟正彬[1] 汪雄武[1] 彭慧娟[1] 周云[1] 秦志鹏[1] 张强[1] 雷传扬[1] 

机构地区：[1]成都理工大学,四川成都610059

出　　处：《中国地质》2012年第1期156-169,共14页Geology in China

基　　金：国家973项目(2011CB403103);中央公益性行业科研专项(200911007-02)联合资助

摘　　要：西藏甲玛铜多金属矿床存在明显的岩浆混合作用,对其研究有助于探测地球的深部过程。本文以构造-岩浆事件理论为依据,根据花岗岩类构造组合特征和成因建立了甲玛矿床所在的冈底斯成矿带的构造-岩浆演化序列,阐述了岩浆混合作用发生的直接原因为岩浆底侵作用,论证了混合岩浆的起源机制(源区继承性),可能为约40%的基性端元(镁铁质岩浆)与约60%酸性端元(花岗闪长质岩浆)在15 Ma左右于源区预混合和就位过程中发生的以机械混合为主的再次混合作用;得出了甲玛矿床成矿流体中的金属元素和S主要来源于岩浆混合作用的幔源铁镁质岩浆,暗示岩浆混合对成矿具有贡献。Lots of evidence shows that magma mingling existed in the Jiama ore deposit.It is of great geological significance to study the magma mingling.Based on tectonic and magmaic theory,this paper has established tectonic and magmaic evolutionary sequence of the Jiama ore deposit in the Gandise metallogenic belt according to structural association features and genesis of the granitoids.It is held that underplating was the direct power in the process of magma mingling,the original mechanism of mixed magma might have been the pre-mingling and emplacement that occurred at 15 Ma 40% basic end-member（mafic magma） and 60% acid end-member（granodioritic gneiss）,and the re-mingling of magma happened again along with mechanical mixture.The metal elements and S in ore-forming fluid came from mantle-derived mafic magma,inmplying that the mingling of magma contributed to mineralization.

关 键 词：镁铁质暗色包体 岩浆混合作用 混合作用机制 成矿的贡献 

分 类 号：P618.41[天文地球—矿床学]