Geochronological study of Caledonian granulite and high-pressure gneiss inthe Dabie Mountains

Using the single-zircon evaporation technique and U-Pb method, the authors have conducted an isotope geochonological study of the Huilanshan granulite and Shima garnet-bearing plagioclase gneiss (''country rocks" of the Shima eclogite) in the Dabie Mountains. The study shows that these rocks have pe ak metamorphic ages of 443-455 Ma, which are essentially consistent with th at of the Caledonian high-ultrahigh pressure eclogites. This indicates the existence of the Caledonian collisional orogeny in the Dabie Mountains.