The magma records and mineralization of early subduction of Neo-Tethyan oceanic slab: Zircon U-Pb and Hf isotopic composition of granitoids in the northwest of Xigaza

The Late Triassic-Middle Jurassic magmatic rocks distributed sporadically in the south of Lhasa terrane are considered to be the magmatic records of the early subduction of the Neo-Tethys. In addition, Xiongcun porphyry copper system was associated with the magma. Therefore, research on the Late Triassic-Jurassic magmatic can help to evaluate its metallogenic potential. This pa-per reports LA-ICP MS zircon U-Pb age and in situ Hf isotopic compositions of the granodiorite in the northwest of Xigaza. The obtained U-Pb zircon age of the granodiorite is 175～180.1Ma. Zircon Hf isotopic compositions of the granodiorite display ε_Hf(180.1Ma)=(+13.4), which shows the characteristics of mantle source with an affinity for island arc which was capable of forming the porphyry Cu-Au system. Therefore, the Late Triassic-Cretaceous volcanic rocks in the south of Lhasa terrane have the potential for exploration of the porphyry Cu-Au system.