A dating of two biotite samples taken from the meso- and low-temperature myloniteswithin the Shangyi-Chicheng fault belt on the north of the North China Craton yields 40Ar/39Ar iso-topic ages of (399 1) Ma and (263 2) Ma, respectively. These data reflect an Early Devonian deformation and a Late Carboniferous retrograde metamorphism event along the fault, suggesting that the tectonic activities of the North China Craton in Paleozoic should be reconsidered.
