中文摘要：

预定和 geochemical 自然的决心早变形并且在喜玛拉雅的 orogen 的 anatectic 事件可以在大规模 collisional 带在构造进化的早阶段期间提供关键卓见进更低的外壳的材料的物理、化学的行为。Yardoi 片麻岩屋顶是向北喜玛拉雅的片麻岩屋顶(NHGD ) 的最东部的屋顶，并且与片麻岩的不同矿物质集合，元素、放射产生的同位素地球化学，以及各种各样的类型包含角闪岩的三种类型。花岗石的片麻岩产量变老的石榴石角闪岩和忍受石榴石的黑云母上的虾锆石 U/Pb 分析将近达到顶点在 45.0 点的变态？

英文摘要：

Determination of the timing and geochemical nature of early metamorphic and anatectic events in the Himalayan orogen may provide key insights into the physical and chemical behavior of lower crustal materials during the early stage of tectonic evolution in large-scale collisional belts. The Yardoi gneiss dome is the easternmost dome of the North Himalayan Gneiss Domes （NHGD）, and contains three types of amphibolites with distinct mineral assemblage, elemental and radiogenic isotope geochemistry, as well as various types of gneisses. SHRIMP zircon U/Pb analyses on the garnet amphibolite and garnet-bearing biotite granitic gneiss yield ages of nearly peak metamorphism at 45.0±1.0 Ma and 47.6±1.8 Ma, respectively, which are 2 to 4 Ma older than the age for partial melting in migmatitic garnet amphibolite （43.5±1.3 Ma）. Available data have demonstrated that ultra-high pressure metamorphism in the Tethyan Himalaya occurred at -55 Ma, and high amphibolite facies to granulite facies metamorphism at 45 to 47 Ma. In addition, partial melting at thickened crustal conditions occurred at 43.5±1.3 Ma, which led to the formation of high Sr/Y ratios two-mica granites. The high-grade metamorphic rocks in the NHGD may represent the subducted front of the Indian continental lithosphere. In large collisional belts, fertile components in crustal materials could melt and form granitic melts with relatively high Na/K and Sr/Y ratios under thickened crustal conditions, significantly different from those formed by decompres- sional melting during rapid exhumation.