Tectonic subsidence reconstruction and sedimentary responses of the Permian Shanxi and Lower Shihezi Formation in central Ordos Basin

The present paper focuses on the quantitative tectonic subsidence reconstruction and sedimentary responses of the Permian Shanxi and Lower Shihezi Formation in central Ordos Basin by using a back stripping method. The tectonic subsidence thickness of the Shanxi Formation ranges from 30 to 95 m, with a maximum subsidence thickness in the central area and gradual decrease towards both the north and south. The secondary subsidence center appears in the norwestern part, with the tectonic subsidence rates from 6 to 20 m/Ma. The tectonic subsidence thickness of the Lower Shihezi Formation ranges from 75 to 110 m, with the tectonic subsidence rates of 9 to 14.5 m/Ma in the central area. Controlled by the differential tectonic subsidence rates, the sedimentary facies types comprise the fluvial, delta and littoral and shallow lake facies, and the fluvial and delta depositional systems have greater scales in the north than in the south. The results of research in this study not only improve our knowledge of tectonic subsidence but also offer an important tool for the research of sedimentary characteristics in the study areas.