1. College of Earth Sciences, Jilin University, Changchun 130061, China;
2. International Centre for Geoscience Research and Education in Northeast Asia, Jilin University, Changchun 130026, China;
3. Jilin Provincial Water Resources and Hydropower Consultative Company, Changchun 130021, China;
4. Shenyang Center of Geological Survey, China Geological Survey, Shenyang 110034, China

Petrography, zircon U-Pb geochronology, whole-rock geochemistry and Lu-Hf isotopic compositions for Toudaogou miarolitic monzogranite in Longjiang area of northern Great Xing'an Range have been studied to investigate their precise geochronological framework, petrogenesis and tectonic setting. The results show that Toudaogou pluton is composed mainly of monzogranite and displays miarolitic structures. The Toudaogou miarolitic monzogranite was emplaced in the Early Cretaceous with an age of 129±2 Ma. Geochemically, these monzogranites are characterized by high silica (SiO₂=74.23%~75.88%), potassium-rich (K₂O=4.45%~5.96%), poor iron (TFe₂O₃=0.86%~1.30%), low Mg^# values (22.5~32.9) and negative Eu anomalies (��Eu=0.50~0.85), with the nature of metaluminous to weakly peraluminous, suggesting that they belong to highly fractionated I-type granite. They are also enriched in LREE and large-ion lithophile elements (LILEs; e.g., Rb and K), and depleted in high field strength elements (HFSEs; e.g., Nb, Ta, Ti, and P), and which bear resemblances to granite formed in an active continental margin setting. Primary zircons from the studied monzogranite have ��_Hf(t) values of +6.6 to +12.3, with juvenile Hf two-stage model ages (T_DM2) of 549 Ma to 760 Ma, indicating that the parental magma was generated by partial melting of Neoproterozoic accreted crustal materials. Combined with the tectonic evolution characteristics of the northern Great Xing'an Range during the Mesozoic, the authors advocated that the generation of the Early Cretaceous miarolitic monzogranite in Longjiang area was related to the lithospheric delamination caused by the westward subduction of the Paleo-Pacific plate.