In this paper, we report on LA‐ICP‐MS zircon U–Pb dates of 14 Mesozoic volcanic rocks from the central Great Xing'an Range (CGXR). These data are integrated with the temporal and spatial distribution of local magmatism‐related Mesozoic mineralization, in an effort to develop an understanding of the geodynamic evolution of the region. Periodic magmatic events in the GXR date from ~1,703 through ~145 Ma. Mesozoic volcanism in the CGXR can be subdivided into three episodes: Triassic (250–205 Ma), Early–Middle Jurassic (182–165 Ma), and Late Jurassic–Early Cretaceous (155–115 Ma). A revision of the previously defined volcanic sequence is offered using a combination of our zircon U–Pb ages and published Mesozoic geological and geophysical evidence from northeast China. We propose that (a) Early–Middle Triassic volcanism in the CGXR resulted from subduction of the Paleo‐Asian oceanic plate; (b) Late Triassic volcanism was related to subduction of the Mongol–Okhotsk oceanic plate (especially near the Erguna Block) and subsequent extension after the closure of the Paleo‐Asian Ocean; (c) Early–Middle Jurassic volcanism was mainly controlled by the southward subduction of the Mongol–Okhotsk oceanic plate; (d) Late Jurassic–initial Early Cretaceous magmatism was initiated by closure of the Mongol–Okhotsk Ocean; and (e) late Early Cretaceous volcanism was induced following the final closure of the Mongol–Okhotsk Ocean and rollback of the Paleo‐Pacific oceanic plate.

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This study presents new zircon U-Pb ages, Sr-Nd-Hf isotopic data, and whole-rock geochemical data obtained from the Early Cretaceous volcanic rocks from the north-western Great Xing'an Range, Northeast China, to constrain the late Mesozoic magmatism and geodynamic setting of this region, which is located in the eastern segment of the Central Asian Orogenic Belt (CAOB). Zircon U-Pb age determinations show that the studied samples formed at 124-114 Ma with an Early Cretaceous magmatic event produced voluminous felsic and minor mafic volcanic rocks. The mafic rocks are dominantly basalt and basaltic andesite, with relatively low SiO 2 contents (49.88-56.64 wt.%). These rocks are enriched in Th, U, large-ion lithophile elements (LILE; e.g., Rb, Ba, and K) and light rare-earth elements (REEs), and depleted in highfield-strength elements (HFSE; e.g., Nb, Ta, and Ti) and heavy REEs (Yb and Lu).The rocks have εNd(t) values of 0.44-0.75 and initial 87 Sr/ 86 Sr ratio of 0.70499-0.70548. These results indicate that the mafic rocks were derived from the partial melting of enriched lithospheric mantle that had been previously metasomatized by subduction-related fluids and experienced variable amounts of fractional crystallization and moderate crustal contamination. In contrast to the mafic rocks, the felsic rocks are dominantly peraluminous trachytes, rhyolites, and dacites with high SiO 2 contents and low MgO contents. These felsic rocks display enriched and variable concentrations of LILEs and REEs, show negative Eu anomalies, and have ε Hf (t) values of +2.6 to +8.3 with T DM2 ages of 1,014-655 Ma, indicating they were derived from partial melting of juvenile crustal materials. These Early Cretaceous igneous rock assemblages record a post-collisional lithospheric extensional setting resulting from the closure of the Mongol-Okhotsk Ocean, consistent with the results of previous studies on the contemporaneous tectono-magmatic activities in NE China.

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In this study, new geochemical, zircon U–Pb, and Lu–Hf isotopic data are presented for volcanics from the Hadataolegai Formation of the central Great Xing'an Range (GXR) in Northeast China. These new data offer insights into the petrogenesis of the volcanics of the Hadataolegai Formation and the tectonic evolution of the Paleo–Asian Ocean (PAO) and Mongol–Okhotsk Ocean (MOO). These volcanics of the Hadataolegai Formation are divided into andesite‐trachyandesites and dacite‐trachydacites. Zircon U–Pb ages show that the volcanics of the Hadataolegai Formation erupted between 230 Ma and 228 Ma during the Late Triassic, which agrees with recently obtained data. The volcanic rocks in this study have low Y (9.9–21.1 ppm) and Yb (0.78–2.02 ppm) contents, high Sr (444–954 ppm) contents, and slight Eu anomalies (δEu = 0.82 to 0.94), similar to ‘adakite‐like’ rocks. The dacites were formed by fractional crystallization of coeval andesitic magmas. The zircons within the andesite and trachyandesite yield higher positive εHf(t) values (+6.3 to +12.0) and model ages (TDM2) between 860 Ma and 453 Ma, which indicates that the magmas were generated by a newly accreted continental crustal source. Moreover, some of the volcanics are relatively high in MgO contents. These characteristics indicate that the volcanic magmas were derived from the partial melting of delaminated lower crust and mixing with mantle materials. Combining these data with previous studies, we suggest that the magmatism in the central GXR was governed by extension due to the closure of the PAO and the back‐arc extension associated with the southward subduction of the MOO plate (western GXR, near the Erguna Block).