Deformation rates of the Minle-Damaying fault from folded fluvial terraces: Implications for kinematics of the Qilian Shan frontal thrust, NE Tibet

Fold-and-thrust belts typically develop in the frontal regions of compressive orogens and are characterized by significant fault offsets and fold deformation. Quantifying their geometry and kinematics is essential for understanding the fault behavior and mechanisms driving mountain uplift and propagation of shortening. This study analyzes a flight of five deformed fluvial terraces along the Tongziba River in the eastern Qilian Shan, northeastern Tibetan Plateau, utilizing high-resolution satellite imagery−derived digital elevation models and optically stimulated luminescence dating to elucidate the kinematics and slip rate of the Minle-Damaying fault. The fault-related folding analysis indicates that the Minle-Damaying fault has a listric geometry, with the fault dip decreasing from ∼40° near the surface to 16°−18° at ∼1 km depth. Vertical uplift rates based on terrace uplift are 1.34 ± 0.21 mm/yr for terrace T5 and 1.29 ± 0.27 mm/yr for T4, while shortening rates derived from balanced cross sections reach 1.94 ± 0.25 mm/yr and 1.87 ± 0.36 mm/yr, respectively. These values exceed those estimated from near-field fault scarp measurements, indicating that localized scarp data may underestimate true deformation. The similarity of shortening rates along different segments of the North Qilian Shan fault supports the interpretation that this fault system plays a key role in accommodating crustal shortening, uplift, and northward propagation of the Qilian Shan.