SHRIMP dating of zircons from the Caledonian Xiongdian eclogite, western Dabie Mountains, China

This note reports the SHRIMP U-Pb data of zircons from the Caledonian Xiong dian eclogite, western Dabie Mountains. Zircons from the rock occur mainly in garnet and other metamorphic minerals with sharp boundaries and exhibit textures growing under metamorphic conditions. Analyses of 7 grains give Pb -206/U-238 ages ranging from 335 to 424 Ma, showing a certain degree of rad iogenic lead loss. This suggests a minimum age of (424 +/- 5)Ma for the met amorphic zircons, as well as the high-pressure metamorphic event. The outer peripheral zone of a zircon gives Pb-206/U-238 age of about 300 Ma. Combin ed with Sm-Nd, Ar-40-Ar-39, U-Pb and Pb-207/Pb-206 ages, the peak metamorph ism of the Xiongdian eclogite is documented between 424-480 Ma.