增生造山带安山质到英安质岩浆的产生机制对理解大陆地壳的形成具有重要意义。本项目拟以发育大量增生杂岩的西藏中部班戈-安多增生造山带为研究区，以出露在混杂岩中佳群岩体中酸性侵入岩和罕见的角闪辉长岩为研究对象，在野外开展大比例尺路线地质填图和岩相学观察基础上，通过系统的单矿物原位成分分析、元素和同位素地球化学测试，鉴定角闪辉长岩（以及其他镁铁质）是幔源岩浆演化的产物还是母岩浆堆晶的产物，限定中酸性岩的源区，刻画角闪辉长岩与中酸性侵入岩的的成因联系和岩浆作用过程，在此基础上讨论部分熔融和分离结晶作用在弧中酸性岩形成中发挥的作用，探讨增生造山带大陆地壳的形成机制。

Formation of calc-alkaline andesitic to dacitic rocks within accretionary orogenic belts are central to understand the mechanism for the formation of continental crust. This proposal sheds lights on the Jiaqun pluton within the Baingoin-Amdo accretionary orogenic belt that is characterized by the presence of extensive accretionary complex, with special emphasis on the calc-alkaline intermediate-felsic rocks and hornblende gabbros (as well as other mafic rocks) which are rare exposed in arcs. Based on the integration of route large-scale geological mapping and petrographical observations, as well as in-situ mineral compositional and whole-rock elemental and isotopic determinations, this proposal aims to (1) constrain whether the hornblende gabbros represent the evolved mantle-derived basaltic magmas or the earlier cumulates crystallized from parental magmas, (2) explore the origin of the intermediate-felsic rocks, (3) reconstruct the genetic links and compositional differentiation between the hornblende gabbros and intermediate-felsic rocks. These results are used to discuss the mechanisms (partial melting and fractional crystallization) responsible for the formation of andesitic to dacitic rocks and formation of continental crust within accretionary orogenic belt.