Closure of the Eastern Paleo-Asian Ocean: Evidence from Permian–Triassic Volcanic Rocks in the Northern Margin of the North China Craton

The Central Asian Orogenic Belt (CAOB) is the world’s largest accretionary orogenic belt, and its formation related to closure of Paleo-Asian Ocean (PAO). However, time style PAO remain controversial. To address these issues, this paper presents zircon U-Pb dating, whole-rock geochemistry Lu-Hf isotope analyses volcanic rocks in Faku-Kaiyuan area on northern margin North China Craton. results show that Bachagou andesites formed Early Permian (287 ± 2 Ma), while Chaijialing dacites Late (253.3 3.7 Ma) Middle Triassic (244.3 1.3 respectively. are enriched LILEs LREEs depleted HFSEs HREEs, indicating they active continental margins. similar geochemical signatures adakite a syn-collisional setting. Geochemistry isotopic analysis indicates were derived from partial melting mantle wedge was metasomatized by subduction fluids. generated slab-derived sediment thickened lower crust. Combined with previous research results, we can conclude Eastern closed scissor-like movement west east during Permian–Middle Triassic.