Sedimentary Characteristics and Shallow Crustal Response to the Tarim Basin‐Altyn Tagh Range Interaction: Constraints From Short‐Period Receiver Functions

Abstract

The Altyn Tagh Range (ATR) and its associated fault system form a tectonic boundary between the Tarim Basin and the Tibetan Plateau, playing a pivotal role in basin subsidence and mountain uplift. While lithospheric models have elucidated deep structural responses to the Tarim Basin‐ATR interaction, shallow crustal structures and deformation mechanisms remain elusive. We developed a Bayesian‐based method that integrates multifrequency receiver functions (RFs) and P ‐wave polarizations to resolve shallow crustal (<10 km) S‐wave velocity (Vs) structures. Applying this method to seismic data from a dense short‐period array across the eastern Tarim Basin (ETB), ATR, and western Qaidam Basin (WQB), we constructed a high‐resolution Vs model with spatial correlation to surface geology, revealing small‐scale tectonic features. The ETB and WQB exhibit low Vs (<2.6 km/s) at shallow depths (<4 km and <3 km, respectively), indicating thick sedimentary successions. In contrast, the ATR displays elevated near‐surface Vs, suggesting a thin sedimentary cover overlying the crystalline basement. The sediment‐basement transition zone is thicker in the ETB than in the ATR and positively correlates with total sediment thickness. Vertical Vs gradients within sediments reflect variations in lithology and compaction. The wedge‐shaped sedimentary layer at the ETB‐ATR boundary aligns with the southeast‐dipping North Altyn Fault; high‐Vs anomalies near the Altyn Tagh Fault are interpreted as deep material intrusions along the fault. These findings suggest that fault‐controlled deformation is the primary mechanism accommodating the underthrusting of the Tarim Basin beneath the northern Tibetan Plateau, providing critical insights into the Cenozoic tectonics of this geological region.