Abstract:Located in the western part of Yabulai—Nuorigong—Honggueryulin belts,Northern Alxa Block,the Yabulai area possesses extensively exposed intermediate—felsic plutons.The main rock types of the Yabulai pluton are granodiorite and monzogranite,mafic microgranular enclave(MMEs) are widely distributed in the pluton. Zircon UPb dating indicates that the Yabulai pluton were formed in the Early Permian,as evidenced by the data from monzogranite(283.4±2.0Ma),granodiorite(277±1.6Ma),the MMEs(284.7±2.4Ma).The MMEs display igneoustexture and most of them are characterized by plastic flow deformation, quenched margin, inversional veins and acicular apatite can be found in some MMEs. The disequilibrium mineral associations or disequilibrium textures are developed in MMEs.The MMEs has similar REE pattern and primitive mantlenormalized traceelement with host granodiorite and monzogranite, there are linear arrays in binary diagrams, exhibits evidence for magma mixing. Combined with previous studies,the authors hold that the Permian magmatism probably formed a magmatic rock belt along the whole northern margin of Alxa Block,and the Permian igneous rocks in the Western Yabulai Mountain might have been formed in an active continental margin setting related to the southward subduction of the PaleoAsian Ocean.