Basement fault control on the extensional process of a basin: A case study from the Cambrian–Silurian of the Sichuan Basin, South‐west China

Abstract

The Sichuan Basin, located on the eastern margin of the Tibetan Plateau, is an intracontinental basin that developed in the Yangtze Block. The Cambrian–Silurian strata in this basin have enormous exploration potential in terms of natural gas, but their structural evolution during the Cambrian–Silurian remains controversial. Based on wells, seismic profiles, aeromagnetic data, and previous research results, this study investigated the structures related to the Leshan–Longnvsi palaeo‐uplift and the activity of the Cambrian–Silurian basement faults, revealing the activity of the extensional process during the Cambrian–Silurian. The results of this study were as follows: (1) the flattening of the bottom of the Permian strata in seismic profiles located in the Leshan–Longnvsi palaeo‐uplift revealed a large number of normal faults, grabens, and horsts in the Cambrian–Silurian strata, indicating that the Leshan–Longnvsi palaeo‐uplift was an extensional structure during the Cambrian–Silurian period; (2) balanced cross‐sections and strata isopach maps showed that all seven basement faults in the basin were normal faults during the Cambrian–Silurian; (3) Sichuan Basin was in an extensional setting during the Cambrian–Silurian; (4) seven basement faults controlled the extensional process during the Cambrian–Silurian in the Sichuan Basin.

Three‐dimensional Geometry and Kinematics of the Changning Anticline in the Southern Sichuan Basin

“…For the Changning anticline and its main controlling fault F 1 along the strike on the border, as a result of the limitation of the seismic data, previous related research achievements are pointing to a corollary: the Changning anticline on the east side of the arch structure limits its eastward extension, while the Mt. Huaying fault zone limits the extension to the west (Qi et al, 2018;Tan, 2018;Zhang, 2018Zhang, , 2020bQiu et al, 2019;Yin et al, 2019;Zhu, 2020;Jiang et al, 2020;Wang et al, 2020;Liu et al, 2021).…”

Paleo-trade wind directions over the Yangtze Carbonate Platform during the Cambrian–Ordovician, Southern China

“…The thickness of the Cambrian succession is ∼100–1500 m, whereas the strata in the western part of the basin are thinner (∼100–500 m) because of the later denudation. The strata in the central part of the basin have a medium thickness of ∼500–1200 m. The strata in the eastern part of the basin are thicker, reaching ∼1500 m (Liu et al 2018; Li et al 2022; Wang et al 2022). The western area contains the Lower Cambrian Dengying, Qiongzhusi, Canglangpu and Longwangmiao formations, the Middle Cambrian Gaotai Formation and the Upper Cambrian Xixiangchi Formation from bottom to top.…”