Trace element discrimination diagrams of metamorphosed zircons from UHP metamorphic rocks. The metamorphic recrystallization proceeds via the mechanisms of solid-state transformation (SST), replacement alteration (RA), and dissolution reprecipitation (DR), respectively. (a) Plot of (Yb/Gd)N versus (La/Sm)N, and (b) plot of Hf versus Nb + Ta. The zircon grains are from low-T/UHP metagranite in the Dabie orogen (Xia et al. 2010). The chondrite element values are after Sun and McDonough (1989).