Zircon SHRIMP U-Pb age and its geological significance in Dongzhongla allgovite, Mozhugongka area, eastern segment of Gangdise, Tibet, China

Allgovite in Dongzhongla area outcrops in the east segment of Gangdese retroarc uplift belt, and the degree of research geology in this area is low. In the past, it was believed that the Dongzhongla allgovite were formed in the Permian of Paleozoic. In order to define accurate forming time of the allgovite in Dongzhongla, firstly we used Zircon SHRIMP U-Pb isotope dating technology and obtained the age of 117.1±1Ma, which is middle of the Early Cretaceous. The age is consistent with both the zonal magmatic flare-up with strong input of mantle derived materials (110 Ma) in the northern parts of the Gangdese and the Gangdese back-arc rift age(120~95Ma).Dongzhongla allgovite is probably the result of the invasion activities during the intra-arc rift stage in the east Gangdese retroarc uplift in the Early Cretaceous, and is related to southward subduction of Bangong Co-Nujiang oceanic crust and northward subdution of Neo-Teths oceanic crust.