A Quintessential Strike‐Slip Contractional Duplex: Deciphering the Geometric Kinematics of the Elashan Fault, NE Margin of Tibetan Plateau, China

Abstract

High‐resolution three‐dimensional (3D) data is pivotal for capturing the intricacies of fault geometry and the subtleties of offset geomorphic markers, providing essential constraints for delineating the spatial characteristics of active faults. By integrating various techniques, we can harness the full spectrum of advantages they offer in acquiring high‐resolution topographic information, thereby enhancing our ability to discern and interpret the complex architecture of fault systems. The geometric structure, and segmentation characteristics of the Elashan fault, located between the Haiyuan and Eastern Kunlun faults, are not yet fully understood, which impeded our comprehensive understanding of the plateau's expansion and deformation process. We use high‐resolution, multi‐scale topographic data to decipher the geometric kinematics of the Elashan fault. We conclude that diverse contractional structures, such as leading and trailing contractional imbricate fans, a contractional duplex, and a dextral left‐stepping restraining bend develop along different segments of the Elashan fault. The geometric and kinematic model of the Elashan fault aligns with that of a typical strike‐slip contractional duplex, accommodating the differences in north‐south crustal shortening on the northeastern margin of the Tibetan Plateau, thus forming a diverse array of strike‐slip compressional tectonic deformation features. We also re‐estimated the slip rate of the Elashan fault in the Xianquan segment to be 2.3–2.9 mm/yr, higher than the result of 1.1 ± 0.3 mm/yr by Yuan et al. (2011), (https://doi.org/10.1130/b30315.1). The significant slip rate on the dextral strike‐slip fault, coupled with the nearly EW‐trending thrust faults, implies substantial interaction within the Haiyuan‐Kunlun “block.”