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The Khanka Massif forms the easternmost part of the Central Asian Orogenic Belt (CAOB) and represents an ideal location for examination of the timing and processes involved in the transition from the Palaeo-Asian to Palaeo-Pacific Ocean tectonic systems. However, it is obstructed because the late Palaeozoic tectonic attributes of the eastern margin of this massif remain unclear. In this paper, we provide zircon U-Pb ages and Hf isotopic, as well as the whole-rock Sr-Nd-Pb-Hf isotopic data for Permian granitic and volcanic rocks within the eastern margin of the Khanka Massif, with the aim of exploring the petrogenesis and their geodynamics significance. These data suggest that the Permian magmatism within the eastern margin of the Khanka Massif, composed of monzogranites and rhyolites, can be split into two stages; i.e. middle (ca. 264 to ca. 263 Ma) and late (ca. 252 Ma) Permian. The highly fractionated middle Permian monzogranites are formed in an N-S extensional setting and represent the magmatic response to the amalgamation of the Khanka and Jiamusi massifs. Middle-late Permian rhyolites with decoupled Nd-Hf isotopic compositions were derived from partial melting of metasedimentary crustal rocks. Their moderate-high zircon saturation temperatures (796–817°C) are thought to represent the involvement of ridge subduction of the Palaeo-Asian Ocean beneath the western margin of the Khanka Massif. Our findings further reinforce the existence of the ridge subduction of the Palaeo-Asian Ocean at the western margin of Khanka Massif in the Permian, while excluding the possibility of Permian Palaeo-Pacific oceanic plate subduction occurred beneath the eastern margin of the Khanka Massif in the Permian. [ABSTRACT FROM AUTHOR]

To investigate the timing of deposition and provenance of early Mesozoic strata in the northeastern North China Craton (NCC) and to understand the early Mesozoic paleotectonic evolution of the region, we combine stratigraphy, U–Pb zircon geochronology, and Hf isotopic analyses. Early Mesozoic strata include the Early Triassic Heisonggou, Late Triassic Changbai and Xiaoyingzi, and Early Jurassic Yihe formations. Detrital zircons in the Heisonggou Formation yield ∼58 % Neoarchean to Paleoproterozoic ages and ∼42 % Phanerozoic ages and were sourced from areas to the south and north of the basins within the NCC, respectively. This indicates that Early Triassic deposition was controlled primarily by the southward subduction of the Paleo-Asian oceanic plate beneath the NCC and collision between the NCC and the Yangtze Craton (YC). Approximately 88 % of the sediments within the Late Triassic Xiaoyingzi Formation were sourced from the NCC to the south, with the remaining ∼12 % from the Xing'an–Mongolia Orogenic Belt (XMOB) to the north. This implies that Late Triassic deposition was related to the final closure of the Paleo-Asian Ocean during the Middle Triassic and the rapid exhumation of the Su–Lu Orogenic Belt between the NCC and YC. In contrast, ∼88 % of sediments within the Early Jurassic Yihe Formation were sourced from the XMOB to the north, with the remaining ∼12 % from the NCC to the south. We therefore infer that rapid uplift of the XMOB and the onset of the subduction of the Paleo-Pacific Plate beneath Eurasia occurred in the Early Jurassic. [ABSTRACT FROM AUTHOR]