Abstract:Some seismic records were found in marlstone interbeds, including grey and black lake facies marlstone, calcilutite, silt mudstone and siltstone in Chaochuan Formation at the northeastern part of Yongkang Basin. The seismites of varied autochthony are the seismic motion signs in the study area. Typical structures of the seismites included micro-fault, seismic fissure bed, liquefied breccia, liquefied vein, dish structures and liquefied convolute. Through the analysis of seismite and its sequence, and combined with the tectonic background of East Zhejiang, the authors supposed that the earthquake events in the middle and upper Chaochuan Formation could be related with the basin-controlling fault activity during the late period of Early Cretaceous. These represent the regional structural-sedimentary transformation from stable compensation deposition period to uplift-erosion period, and are of isochronous and important significance for the stratigraphic division of terrestrial facies basin.