Discovery and Recognition Marks of Seismite of the Fei 1 Member in the Eastern Sichuan Basin

Key words: 
• sedimentary sequence

Abstract: Syndepositional deformation structures were well developed in the Fei 1 Member nearby the Hua Yingshan fracture belt in the eastern Sichuan Basin. Based on studies of regional tectonic setting and observation of geologic crosssections and drilling cores, it is concluded that these structures, such as liquefied vein, gravity fault, bedding phenomenon, enterolithic structure, flamme structure, convolute beddings were mainly produced by seismic liquefaction. According to recognition marks and combination characteristics, seismic sedimentary process can be divided into autochthonous seismite(A), tsunamite(B) and background deposit(C) units, of which unit A consist of liquefied vein(a), seismic corrugated rock(b) and shattering rock, which are associated into two types of associations: abc(A1) and bc(A2). The sedimentary sequence of seismite of the Fei 1 Member in the eastern Sichuan Basin is A1BA2C. Combining with the cognizance of regional tectonic setting, it indicates that the seismite is in connection with the Hua Yingshan fracture belt, and the seismic activities due to the activities of the Hua Yingshan fracture belt provided dynamics for the developing of seismite of the Fei 1 Member in the eastern Sichuan Basin.