The 3D Growth Pattern of Structural Wedge: Insights From Yingjisha Anticline in the West Kunlun Piedmont, NW Tibet

Abstract Structural wedges, defined as contractional structures comprising kinematically linked forethrust and backthrust, represent a fundamental structural element in fold‐and‐thrust belts. Synchronous displacement on both thrust faults drives the wedge into the surrounding rocks, creating distinctive uplift and folding patterns. While previous 2D analyses have established their kinematic configurations, resolving their 3D growth patterns remains challenging. In this study, we identify a WNW‐trending structural wedge beneath the Yingjisha (YJS) anticline in the West Kunlun piedmont, and characterize its 3D growth pattern through high‐resolution 2D seismic reflection profiles, geometric and kinematic analyses, and 3D structural model. Structural forward modeling and quantitative analysis of fault slip reveal the synchronous slip on the forethrust and backthrust, demonstrating that the YJS anticline is controlled by a structural wedge. The ages of growth strata document a progression from 1.26 ± 0.11 Ma in the core to 0.85 ± 0.11 Ma in the eastern plunging termination, indicating lateral growth of the YJS anticline, with an eastward lateral growth rate of 35–84 km/Ma. Furthermore, through 3D structural model, we discover the consistency of the fault geometry along the strike. Two other natural structural wedges (Kashi and Dafengshan anticlines) validate this discovery, suggesting that undeformed segments inherit fault geometry from adjacent deformed segments along the strike, which may represent a common characteristic of structural wedges dominated by lateral growth. Our results not only establish a framework for understanding the 3D lateral growth of structural wedges, but also provide new insights into the formation and evolution of fold‐and‐thrust belts worldwide.