LA-ICP-MS zircon U-Pb ages of tectonic-thermal events in the Yalaxiangbo dome of Tethys Himalayan belt

Paleozoic-Cenozoic rocks and strata together with intense ductile shearing and magmatic thermal events occurred in the Yalaxiangbo (Yardoi) dome of eastern Tethys Himalayan belt, which well recorded the structural deformation and thermal history caused by northward subduction of the Indian Continental Plate. LA-ICP-MS U-Pb isotopic dating of zircons with clear growth zonation selected from granitic rocks sampled in different structural zones reveals high-resolution ages of four periods of tectonic-magmatic events that took place in the Yalaxiangbo dome. The U-Pb isotopic ages of zircons, 520.4±6.3Ma and 536±12.3Ma, are indicative of magmatic emplacement of the Pan-African orogeny in the crystalline basement of the Himalayan block. The other U-Pb isotopic ages of zircons reveal geological epochs of tectonic-thermal events during Cenozoic collisional orogeny, e.g., ages 45.6±1.2~44.16±0.88Ma are indicative of the initial time of the northward subduction of the Indian Continental Plate, 35.00±0.48Ma is a representative age for Late Eocene tectonic-thermal event that occurred in the depth of the thickened crust, and 15.67±0.50Ma indicates the epoch of the emplacement of the core granite and the formation of the Yalaxiangbo dome.