Single-zircon U-Pb dating of the Liugouxia granitic gneiss in the western segment of the North Qilian Mountains

Abstract: The Liugouxia granitic gneiss is an old granitic intrusion divorced from the metamorphic complex of the Beidahe Group-complex found during 1:50000 regional survey of the Yu'erhong Sheet. Single-zircon U? Juan Pb dating yielded ages of 1463 ± 74Ma and 623 ± 138Ma. The two ages coupled with the results of regional survey suggest that the former age represents the age of emplacement of the old granitic intrusion, while the latter, the age of the deformational-metamorphic thermal event overprinted in the late stage. The two ages furnish direct evidence for the determination of the continental break-up and collisional orogeny in the early stage in the North Qilian Mountains.