从岩浆岩看青藏高原地壳的生长演化  

Growth and Evolution of Crust of Tibetan Plateau from Perspective of Magmatic Rocks

作　　者：莫宣学[1] Mo Xuanxue(School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国地质大学地球科学与资源学院,北京100083

出　　处：《地球科学》2020年第7期2245-2257,共13页Earth Science

基　　金：国家自然科学基金委重点项目(No.40830317);国家重大基础研究(973计划)项目(Nos.2002CB4126,G1998040800);自然资源部重大项目(No.9501101)。

摘　　要：青藏巨厚陆壳的性质和形成机制,是重要的科学问题.通过对青藏岩浆岩,特别是其Nd、Hf同位素的研究,证明青藏高原并存着新生地壳和再循环地壳两类地壳.地壳的结构和属性对成矿矿种、矿床类型和分布有重要的控制作用.青藏巨厚地壳是由两种机制(构造加厚;地幔物质通过岩浆作用注入加厚)共同造成的,二者贡献比例约6∶4.地壳增厚主要发生在50~25 Ma期间.大陆碰撞带是造成地壳净生长的重要构造部位.The nature of the Tibetan extremely thick crust and its thickening mechanism are important scientific problems.According to the investigation of igneous rocks,especially Nd and Hf isotope studies,it proved the coexistence of two types of crust(juvenile and reworked)in the Tibetan Plateau,which controls the distribution of different types of ore deposits.The Tibetan crustal thickening was made by both tectonic compression and the input of mantle components carried by magmatism.The timing of the Tibetan crustal thickening was likely in the period of 50-25 Ma.Continental collision zones may be sites of net crustal growth through process of syncollisional magmatism.

关 键 词：青藏高原两类地壳 新生地壳 再循环地壳 青藏地壳增厚机制 地壳增厚的时间 岩石学 

分 类 号：P313.2[天文地球—固体地球物理学]