Abstract:Objectives: A large number of granite bodies are exposed in the Wuland area adiacennt to the Dulan UHP terrain. In addition to a few studies, the geochemical characteristics and genesis of these granites and their tectonic significance are almost not much studied. Especially, the genetic relationship between the granites from Wulan and others in the North Qaidam UHP belt remains unclear. Therefore, our research focuses on the petrogenesis of the granite and its regional tectonic significance. Methods:Based on the field work, through the microscope observation, the whole rock chemical analysis and the Sr—Nd isotopic analysis of the granites, we determine the the granite affinity and petrogenesis. Combined with regional tectonic characteristics and other research achievements of granite in North Qaidam, we discuss the tectonic significance of granite from Wulan. Results:Gechemically, most of the granites from Wulan area, northern Qaidam belong to magnesian calcalkaline series, a few to iron alkalicalc and alkaline series. The early granite is not only enriched in large ion lithophile elements(LILE), but also enriched in part of high field strength elements(HFSE)(such as Zr, Y, Nb), which belongs to Atype granite. The late granitoids are enriched in LILE and light rare earth elements (LREE), depleted in HFSE, and had LREE differentiation to be obvious but heavy rare earth element (HREE), with a weak negative Eu anomalies in REE patterns, which belongs to the Itype granite. The isotopic geochemistry shows that the 87Sr/86Sr ratio of the early granitoids is 0.7108 and Nd model age (T2DM) 2.10Ga, higher than those of late granites (87Sr/86Sr =0.7076 ~ 0.7107, T2DM=1.41Ga ~ 1.58Ga), but εNd(t) value of late granites (-11.6) are lower than that of the early granite (-4.8 to -6.8), indicating that early granite may originate from the Paleoproterozoic continental crust and the late granite from the Middle Proterozoic basaltic crust. Conclusions: This study shows that the early granitoid in Wulan area are related to the Qilian lithospheric delamination, which causes the thinning and stretching of Oulongbuluke continent block, also marks the beginning of Zongwulong rift; and the lategranitoids in the area are related to the oceanic crust subduction of Zongwulong under the Oulongbuluke continent block.