Natural Resources Survey Institute of Heilongjiang Province, Harbin 150036, China 

 The Xunke pluton is mainly composed of syenogranite, and it is located in northern Lesser Khingan Range. LA??ICP??MS zircon U??Pb dating results indicate that the Xunke pluton was formed in the Middle Silurian (424 ± 6) Ma. The granite samples are high in w( SiO2 ) of 65. 90%??72. 63% , w(Na2O + K2O) of 8. 87%?? 10. 18% and w(Al 2O3 ) of 13. 17%??17. 15% , belonging to a high potassium?calcium?alkaline, quasi Aluminous rock series. Xunke pluton has strong negative Eu anomaly, enriched in large ionic lithophile elements (Rb, Th, K, Ba), depleted in high field strength elements (Nb, Ta, Ti) and P, Sr. The total amount of rare earth elements is high, and the ratio of light and heavy rare earth elements (LREE / HREE) suggests a light rare earth enrichment type. The rock is I type. The low Sr and high Y characteristics imply that the magma originated from partial melting of the middle and upper crust. Combined with previous research, it is suggested that the Middle Silurian granites in the northern Lesser Khingan Range are related to the collisional convergence of the Songneng and the Jiamusi massif.