Abstract: The granitoid gneisses in the northern Jiamusi massif is suitable for dating by Chemical Th-U-Total Pb isochron method （CHIME）.Monazite dating of 415 Ma indicates a magmato-thermal event in the Late Silurian. The dating results of （494.36 ± 23.6 ）Ma,（506.96 ± 52.20）Ma and（481.04±23.19）Ma provide the conclusive evidence for a 500 Ma Late Pan-African high-grade metamorphic event in the northern Jiamusi massif. Combined with the SHRIMP U-Pb zircon dating results from the southern Jiamusi massif, it is concluded that the entire Jiamusi massif has undergone a 500 Ma high-grade metamorphic event. The Jiamusi massif and Songnen massif could have amalgamated and linked together before and were affected variously by metamorphic event during 500 Ma.

Key words: Jiamusi massif, granitic gneiss, monazite method (CHIME) dating