Abstract: In the lower Cretaceous drilling cores of Baiyinchagan Depression, Erlian Basin, two types of special geological phenomena are discovered, of which the syn-depositional plastic deformations and saucer-shaped structures belong to deformation,and the micro-faults, net-shaped fractures, sand dykes and syn-depositional breccia belong to cracking. The special geological phenomena were initiated by the outside viberation and are characterized by seismites. The deformation phenomena were mostly formed during the non-solidification-semisolidification phase, and the cracking often came into being after the diagenesis. The micro-faults, net-shaped fractures and sand dykes were attributed to the extensional stresses. The special geological phenomena were abundantly distributed in the Tenggeer Formation and Du 1 Member of Duhongmu Formation, and they gradually evolved from cracking into deformation upwards along the vertical direction. The research also showed that they were related to the tectonic background of regional extension and the activities of palaeo-faults and palaeo-earthquakes, of which the intensely active faults and strong earthquakes often caused cracking and the gently active faults and weak earthquakes mostly caused deformation.