1. College of Earth Sciences, Jilin University, Changchun 130061, China;
2. No. 243 Geological Party of Nuclear Industry, CNNC, Chifeng 024000, Inner Mongolia, China

The authors discusse the origin and evolution mechanism of tonalitic gneisses from Banshigou area of southern Jilin. It is indicated that the TTG gneisses are characterized by high Si(SiO₂=66.61%~72.35%), Al(Al₂O₃=13.56%~16.18%) and Na(Na₂O=3.65%~4.69%), but low K(K₂O=1.13%~2.25%). The chondrite normalized REE patterns are characterized by right inclining type. Trace element analysis shows the enrichment of large ion lithophile elements (e.g., Ba and Rb) and strong depletion in high field strength elements (e.g., Ni and Ta).The gneisses belong to the high aluminum TTG gneisses with geochemical characteristics similar to the high silicon adakite. LA-ICP-MS zircon U-Pb age data indicate that the rocks were crystallized at (2 619±28)Ma, so they are formed in Neoarchean. Zircon Lu-Hf isotopic analyses show that the magma is rarely mixed with the mantle material during its evolution, and the corresponding two-stage model age(T_DM2) is mainly between 2 976 Ma and 2 675 Ma.Therefore, tonalitic gneisses of Banshigou area are probably produced by partial melting of basaltic oceanic crust in the subduction environment. The authors suggest that there probably existed an orogenic belt (Ji-Liao-Ji arc-continent collision orogenic belt) in Neoarchean in the northeast North China Craton.