Sheng Lu ^1* Chenglu Li ^1* Masroor Alam ² Zhichao Song ³ Xiannan Zhu ⁴ Anzong Fu ¹ Wenpeng Yang ¹

• ¹ Heilongjiang Provincial Natural Resources Investigation Institute, Harbin, China
• ² Department of Earth Sciences, Karakoram International University, Gilgit, Gilgit Baltistan, Pakistan
• ³ The Fifth Geological Exploration Institute of Heilongjiang Province, Harbin, Jilin Province, China
• ⁴ Harbin Center for Integrated Natural Resources Survey, China Geological Survey, Harbin, Jilin Province, China

The occurrence of intrusive rocks within the Xinlin area, northeastern China, provide insights into the Neoproterozoic–Mesozoic geodynamic setting of the Erguna block. In this study, we present petrographic, geochemical, and geochronological data for intrusive rocks from the Xinlin area. Zircon U–Pb and muscovite 40Ar/ 39Ar geochronology reveal that magmatism occurred during the Neoproterozoic (ca. 864.98 Ma), Early Ordovician (ca. 470.0Ma), Late Carboniferous (ca. 306.9 Ma), Early Permian (ca. 296.9 Ma), and Early Cretaceous (ca. 117.8 Ma). The Neoproterozoic and early Ordovician intermediate–mafic intrusive rocks have low Rb/Sr contents, high Mg#, and weakly negative Eu anomalies. These results suggest that the magma sources of these rocks varied: intermediate–acidic magmas were derived from the lower crust, and the intermediate–mafic magmas were originated from the mantle and subsequently contaminated by crustal material. In contrast, the Late Carboniferous, early Permian, Late Triassic - early Jurassic, and Early Cretaceous intermediate–acidic intrusive rocks display high Rb/Sr contents, low Mg#, and strongly negative Eu anomalies, indicating derivation from the partial melting of the lower crust. Our findings, along with previous studies, suggest that the Neoproterozoic intrusive rocks formed during the breakup of the Rodinia supercontinent. The Paleozoic intrusive rocks associated with the collision and amalgamation of the Erguna and the Xing'an blocks, as well as the Songnen and Xing’an blocks. Early Mesozoic intrusive rocks were developed during the subduction of the Mongolian Okhotsk oceanic intracontinental system. Finally, the late Mesozoic intrusive rocks formed during non‐orogenic extensional setting, potentially linked to the final closure of the Mongolian–Okhotsk Ocean or the rollback of the Palaeo‐Pacific Plate.