Climatic and Tectonic Controls on Late Quaternary Fluvial Terrace Development in the Turpan Fold–Thrust Belt, Eastern Tianshan

Fluvial terraces provide important archives for understanding the relative roles of tectonics and climate in landscape evolution. Here, we investigate late Quaternary fluvial terraces in the tectonically active Turpan fold–thrust belt (FTB) of the eastern Tianshan using geomorphic surveys, unmanned aerial vehicle (UAV)-derived topography, and optically stimulated luminescence (OSL) dating. Our results show that terrace aggradation occurred mainly during marine isotope stage (MIS) 3c (ca. 50 ka), MIS 3a (ca. 35–27 ka), and early MIS 1 (ca. 11 ka), broadly corresponding to relatively humid intervals documented in regional paleoclimate records, suggesting that the aggradation and abandonment of fluvial terraces in the Turpan FTB were mainly driven by climate-induced changes in the Qs/Qw ratio. Previous studies show that tectonic deformation enhanced the magnitude of river incision in the central Turpan FTB. Combined with regional paleoclimate records and the tectonic activity, we suggest that climate-induced changes in hydrological conditions control the timing of terrace aggradation and subsequent abandonment, whereas tectonic uplift may influence the magnitude of river incision and promote the long-term preservation of terraces in the Turpan FTB.