Preliminary Study on the Isotopic Age of Metamorphism and Anatexis of the Fuping Group of the Environs of Xiaojue, Pingshan County, Hebei Province CHENG Yuqi, WAN Yusheng and GAO Jifeng(Geological Institute, Chinese Academy Geological Sciences, Beijing, 100037) Part of the metamorphic rocks of the Early Precambrian Fuping Group of the study area have been subjected to differential anatexis shortly after the climax of regional metamorphism. Isotopic age studies of the zircons from both the metamorphic rocks and their anatectic derivatives by the single crystal U-Pb method have been carried out by the authors. The upper intercept age of the U-Pb concordia has been interpreted as the age of metamorphism or anatexis of the samples concerned. The results of the isotopic determination of zircons from the samples of three different rock types collected near Xiaojue and in the area further east(Fig. 1) give the age of regional metamor-