Resumen de Amplitude calculation of the end-Permian sea level drop in Northeastern Sichuan Basin, China
Rui Zhao, Jiahui Zhao, Yang Li, Yu Liang, Yasheng Wu, Enguang Qi
An extensive unconformity surface has been reported on top of the Changxing Formation in northeastern Sichuan Basin, which was formed by the end-Permian sea level drop globally. The amplitude of sea level change has never been studied in Changxing Formation, however, this is a problem of vital importance in petroleum exploration. Logging curves of boreholes located in Longgang, Puguang and Yuanba areas are used to analyze the intensity of karst, which can be used to represent the amplitude of sea level drop. Four, two and two logging phases are identified in Longgang, Yuanba and Puguang areas, respectively, which indicate different combinations of sedimentary facies and diagenesis features. By analyzing the thickness of karst formations in the studied sections, the amplitudes of sea level drop are identified in different areas. Combined with karst features reflected from Permian Panlongdong Outcrop, the amplitude of end-Permian sea level drop is at least 190 m in Sichuan Basin.
