Fault-driven exhumation in the southeastern margin of the Tibetan Plateau: Thermochronological insights into Cenozoic crustal deformation

The southeastern margin of the Tibetan Plateau exhibits a complex tectonic evolution and distinctive geomorphic features, yet previous studies have been limited in scope, lacking comprehensive comparisons across key regions. In this study, we present a substantial new dataset of low-temperature thermochronology, providing critical constraints on the region’s exhumation history. By integrating these results with existing geomorphological, structural, and geophysical evidence, we offer a more comprehensive perspective on the differential uplift and fault activity that have shaped the southeastern Tibetan Plateau during the Cenozoic. More specifically, exhumation along the Jinhe-Qinghe thrust belt exhibits significant along-strike differences, with the northern segment experiencing more substantial late Cenozoic thrusting and exhumation compared to the southern segment. It is suggested that present-day thermal history contrasts across the fault may, in part, reflect inherited topographic features rather than mere recent tectonic processes. In addition, low-temperature thermochronological data indicate that the Miocene was a key period of crustal shortening and deformation across the southeastern Tibetan Plateau, with widespread evidence of rapid cooling and exhumation along major fault zones during this time. Our findings further demonstrate that late Cenozoic crustal deformation, uplift, and shortening in this region have been predominantly controlled by large-scale fault systems. In contrast, the regions between these major faults exhibit significantly older cooling ages and a more stable thermo-tectonic history, suggesting limited late-stage exhumation. Finally, contour maps of thermochronological ages of the southeastern Tibetan Plateau illustrate systematic spatial variations in exhumation, reinforcing the critical role of fault-controlled deformation.