magma facies
1.Based on the studies of petrotexture, structural deformation and the relevant metamorphism, this paper indicates that this peridotite massif is the product of ultramafic magma cumulated at the crust-mantle transtion zone and has undergone the early stage of plastic deformation under the condition of granulite facies（≥800℃）and late ductile shearing at amphibolite and greenschist facies in relevance to uplifting.
2.The age of adakitic dacite is about 514.2± 8.5 Ma, and the age of eclogite from the northern margin of Qaidam basin is 494.6±6.5 Ma. Therefore, it is considered that the slab started its subduction in Late Cambrian, that the adakitic magma was formed at the subduction depth of about 75～85 km, and that the partial melting residues with garnet facies continued subducting and finally formed eclogite in Early Ordovician.
