Characteristics and geological significance of seismites of Paleogene in Yangxin Subsag of Jiyang Depression

Seismite is a type of catastrophic deposits with recognizable evidence for seismic activities and sequence. According to core observation and description, many deformation structures with seismite characteristics are recognized within sandstone and shale sedimentary strata of Paleogene continental faulted basin in Yangxin Subsag, such as micro-faults, earthquake fissures, liquefaction sandstone veins, water-escape structure, vibrational liquefaction deformation structure, seismic pillow structure and associated structure, etc. The vertical sequence of seismites in Yangxin Subsag, in ascending order, is underlying unshocked layer, micro-faults layer, autoclastic shattered breccia layer, vibrational liquefaction deformation structure layer, seismic pillow structure and associated structure layer, liquefied homogeneous layer and overlying unshocked layer, which corresponds to different earthquake intensity respectively. The discovery of seismites can be used to analyze the intensive activity stages of basin-controlling boundary fault, and seismite itself is a kind of potential reservoir, so it has important geological significance for studying earthquake event deposit.