西藏冈底斯过铝花岗岩的岩石成因及其对冈底斯地壳生长的约束

项目名称： 西藏冈底斯过铝花岗岩的岩石成因及其对冈底斯地壳生长的约束

项目编号： No.41272091

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 廖忠礼

作者单位： 成都地质矿产研究所

项目金额： 89万元

中文摘要： 过铝花岗岩一般与中上地壳富Al变沉积岩的重熔有关，其中保存了大量继承锆石。通过研究其来源和岩石成因，不但可揭示中上地壳的物质组成，而且还将为构造中上地壳的变沉积岩物源区提供重要约束。在申请者前期预研和其它研究基础上，以出露于冈底斯不同地区不同时代（早、中侏罗世,早白垩世、始新世、中新世）过铝花岗岩为对象，进一步开展野外调研和详细的岩石矿物学研究，分析过铝花岗岩的地球化学组成和锆石Hf同位素，讨论其岩浆起源和岩石成因；再重点针对过铝花岗岩的继承锆石年龄和Hf同位素成分，通过与冈底斯带变沉积岩中碎屑锆石年龄和Hf同位素的对比，建立冈底斯带过铝花岗岩和变沉积岩的锆石年龄和Hf同位素指标，通过与邻近陆块的对比，分析冈底斯的地壳生长。项目成果不但将对冈底斯带过铝花岗岩的侵位时代和岩石成因提供重要约束，而且还将为研究冈底斯带的构造起源提供依据。

中文关键词： 地壳生长；岩石成因；碰撞；过铝花岗岩；西藏冈底斯

英文摘要： In general, peraluminous granite relate to the remelting of metasedmentary with rich Al in mid-upper crust, and which keeps a supply of inheritance zircon. Through the research of the source and the petrogenesis, not only can be revealed in the material composition of crust, and will also provide important constraint to construction the origin area of metasediment in mid-upper crust. In the early pre-research of applicants and other researchbased, there are promote field survey and detailed mineralogical research of rock., As research Objects, peraluminous granites exposure in different areas and different age, (early, middle Jurassic, and early cretaceous, Eocene, Miocene), analyzed the geochemical composition and zircon Hf isotopes of peraluminum granite, and discuss the magma origin and petrogenesis. Then focused on the age of inherited zircon in peraluminum granite and Hf isotope composition, through the contrast between inherited zircon and Hf isotope of metasediment in Gangdese, build the zircon age and Hf isotope index of peraluminous granite and metasediment in Gangdese. Through the contrast with neighboring continental block, analyse the crustal growth of Gangdese. Project achievement not only to provide important constraints to invasion era and petrogenesis of peraluminous granite in Gangdese, but als

英文关键词： crustal growth；petrogenesis；collision；peraluminous granite；Tibet Gangdese