1. College of Earth Sciences, Jilin University, Changchun 130061, China;
2. International Center for Geoscience Research and Education in Northeast Asia, Jilin University, Changchun 130026, China

To determine the petrogenesis and tectonic setting of Late Paleozoic granitoids in Great Xing'an Range, NE China, the authors undertook zircon U-Pb dating and geochemical analysis on samples from monzogranites in Yaergenchu area. Zircon U-Pb age dating indicates that the monzogranites in the studied area were emplaced in the Late Carboniferous (312±2 Ma). The monzogranites contain high SiO₂ (75.16%~75.32%) and Na₂O+K₂O (8.45%~8.76%), but low MgO (0.12%~0.14%). Moreover, the samples are characterized by the enrichment of large ion lithophile elements (e.g., Rb, Ba, Th, U, K) and light rare earth elements, but depletion of Nb, Ta, Ti and P, with ε_<sub>Hf(t) values of +3.5 to +9.5 and Hf two-stage model ages of 1 103~715 Ma, indicating that the parental magma was derived from partial melting of juvenile crustal material. Integrating the geochronological data, geochemical features and regional geological observations, it is suggested that the formation of Late Carboniferous monzogranites in the studied area was related to the subduction of the Paleo-Asian oceanic plate beneath the Xing'an terrane.