Transition from fault-propagation folds to fault-bend folds determined by along-strike variations of structural styles and fault displacement-distance relationships: The Sumatou anticline, Sichuan Basin, China. (February 2020)

• Record Type: Journal Article
• Authors: Jiang, Danqi; Wang, Maomao; Song, Gonghua; Yan, Bing; Feng, Wang
• Is Part Of: Journal of structural geology. Volume 131(2020)
• Publication Date: 2020-02
• Subjects: Thrust-related fold -- Fault-propagation folds -- Fault-bend folds -- Fault displacement-distance profiles -- Along-strike transition -- Sichuan basin; Geology, Structural -- Periodicals; Géomorphologie structurale -- Périodiques; Geology, Structural; Periodicals; 551.805
• DOI: 10.1016/j.jsg.2019.103951
• Languages: English
• ISSNs: 0191-8141

Abstract

Abstract: Understanding the evolution of thrust-related folds requires knowledge of their structural deformation over time and space, which is important for analyzing subsurface structures, hydrocarbon traps, and seismotectonic models. Here, we use high-quality 3-D seismic data interpretation and modeling to construct the subsurface structure of the Sumatou anticline in the Sichuan Basin, China. We focus on the effects of structural styles and fault displacement-distance relationships on along-strike variations in the fold deformation mechanism. Seismic interpretation reveals the along-strike variation in structural styles that formed by slip on a northwest dipping thrust fault. The fault displacement-distance profiles reveal that this structure generally follows a linear decreasing relationship, which is consistent with the pattern of fault-propagation folds (FPF). The northern segment illustrates a planar thrust ramp and self-similar growth characteristics. In contrast, the central and south segments exhibit a distinct structural style of fault-bend folding that maintains the linear decreasing trend of fault displacement-distance relationships, which is inconsistent with fault-bend folds model (FBF) prediction. We simulate three possible fault-bending and propagating kinematic models to verify the fault displacement-distance profiles. The simulations reveal that the Sumatou anticline transitioned from early stage FPF to FBF during lateral growth. We suggest that this transition may exist in a variety of tectonic settings, such as the Sichuan Basin, the Nankai Trough, and the Niger Delta, which can be revealed by analyses of fault displacement-distance profiles and structural style variability. Highlights: We reveal the along-strike transition of fault-propagation folds (FPF) to fault-bend folds (FBF). The along-strike variations of structural styles and fault displacement-distance profiles were investigated. The structure transitioned from early stage FPF to FBF during lateral fold growth. Structural style variations are attributed to different folding deformation stages. The FPF to FBF transition exists in a variety of contractional tectonic environment.