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

Abstract

In this study, we aim to clarify the structural characteristics and deformation process of the Changning anticline. We carefully interpret 38 two-dimensional (2D) seismic profiles in the study area and establish three-dimensional (3D) geometric and quantitative kinematic models of the Changning anticline. This study shows that the basement fault controls the formation of the Changning anticline. The fault slope of the main fault in the basement shows 'steep in the upper and gentle in the lower' structural characteristics vertically, possessing obvious segmentary characteristics transversely and presents the overall characteristics of 'steep in the east and gentle in the west'. Further analysis shows that the Changning anticline proceeds west and terminates at the boundary defined by current surface features but gradually disappears westward across the Mt. Huaying fault zone. Furthermore, we identified that deformation of the Changning anticline began during the early Yanshanian movement period. Under compressional stress from the southeast, the anticline slid forward along the basement fault until the end of the Yanshanian movement period, when the dominant WNW-ESE structure gradually emerged. Since the Himalayan movement period, a series of NE-trending structures have been formed in the anticline, owing to multi-directional compressive stress.

A study of Mesozoic–Cenozoic tectonic evolution of the Tarim Basin with S‐wave receiver functions

“…(c) Bouguer gravity anomaly (Hou & Yang, 2011); (d) Aeromagnetic anomaly (Yuan, 1996). (e) Resistivity profile obtained from magnetotelluric data (Yang, Xu, et al, 2015; Yang, Zhang, et al, 2015; Zhang et al, 2020), resistivity scale is shown at right panel, blue denotes high conductivity, and red denotes high resistivity. (f) Migration image of SRF along profile AB.…”

“…In this paper, the deep structure and Mesozoic‐Cenozoic tectonic evolution are discussed by combining the RF with the density, electrical and magnetic results of the Tarim Basin. Figure 6c–e are bouguer gravity anomalies along the profile AB (Hou & Yang, 2011), reduction to pole of the aeromagnetic anomalies (Li, Li, Zhou, et al, 2014; Yuan, 1996) and a resistivity profile obtained using magnetotellurics (Yang, Xu, et al, 2015; Yang, Zhang, et al, 2015; Zhang et al, 2020).…”

“…The resistivity inversion results show that the Tarim Basin is a downfaulting craton basin with a lithosphere thickness of 138 km. However, the conductivity structure of the Tarim Basin does not find large‐scale basalt characteristics in the basin basement, which does not support the TLIP (Yang, Xu, et al, 2015; Yang, Zhang, et al, 2015; Zhang et al, 2020). The gravity field of the Tarim Basin shows that there is a near east–west trending gravity high‐value zones in Bachu area (Hou & Yang, 2011), which may be related to the intense uplift of basement in central Tarim.…”