Abstract: The Paleo-Tethyan Ocean, represented by the Jinshajiang River suture in eastern Tibetan Plateau, was consumed and closed in the Early-Middle Triassic period, but the specific process after the oceanic crust demise still poorly constrained. The potential for porphyry copper mineralization of magma generated in post-subduction setting remains unclear. In present study, geochronological and geochemical analyses were carried out on the Yarigong pluton in Batang area. Magmas were intruded in Late Triassic as corroborated by zircon U-Pb mean age of ~227 Ma. Rocks from this intrusion were characterized by high SiO₂ (65.5~67.6 wt.%) and Mg# (53~64), as well as high initial ⁸⁷Sr/⁸⁶Sr values (0.7098 ~ 0.7118) and low εNd(t) values (-7.4 ~ -8.0). Magma generation of the Yarigong pluton was resulted from interaction between melts derived from continental crust and peridotite mantle, partial melts of the continental crust was likely associated with the break-off of early subducted Paleo-Tethyan oceanic slab. Geochemical compositions of amphibole and zircon suggest high magma H₂O contents (>5 wt.%), the oxygen fugacity of magma is lower than magma related to typical porphyry Cu deposits, and extremely low S in magma was indicated by consistent low SO₃ in apatite. These conditions imply barren magma for porphyry Cu deposit formation.