line-height-rule: exactly" class=MsoNormal>Based on the investigation of field geology, detailed zircon U-Pb age measurements were done on the Hunandong granite. According to the result together with other information published, the authors think that the formation of Hunandong granite may be related to the amalgamation and collision between Cathaysian block and Yantze Block, providing strong evidence for further understanding the Caledonian magmatism and its geodynamic process in