Tectonic transition in the northeastern Tibetan Plateau: from tectonic escape to mountain building

The northeastern Tibetan Plateau is bounded by two major left-lateral strike-slip faults: the Altyn Tagh and Haiyuan faults. Eastward crustal motion along these faults, driven by the ongoing Indo-Asian continental collision, diminishes progressively toward their eastern terminations. Here, the crustal deformation is dominated by crustal shortening, thrust faulting, and uplift, which collectively contribute to the lateral growth of the plateau. Understanding this tectonic transition is essential for interpreting the plateau’s expansion and the seismic hazard along its northeastern boundary. We integrated InSAR, GNSS, and precise-leveling data to reveal the present-day crustal deformation in the northeastern Tibetan Plateau. Our analysis indicates that eastward motion along the Altyn Tagh fault is absorbed by thrusting and uplift within the Qilian Shan. Similarly, the Haiyuan fault transitions into crustal shortening and uplift in the Liupan Shan orogen. These transitions are largely controlled by the geometry of the strike-slip faults and the presence of the rigid Alashan and Ordos blocks to the east, which impede eastward motion of the Tibetan crust. Our results of present-day crustal deformation align with late-Cenozoic geological structures in northeastern Tibet and the stress patterns inferred from earthquakes along its northeastern margins, supporting a consistent model of ongoing plateau growth through transitioning from the escaping tectonics to mountain building.