Mesozoic-Cenozoic cooling history of the Eastern Qinghai Nan Shan (NW China): Apatite low-temperature thermochronology constraints

Understanding the formation of Qilian Shan in NE Tibetan Plateau provides insights into growth mechanisms northern portion plateau through time. The onset time exhumation is still debated. Qinghai Nan subrange, located southeastern Shan, cut by Yellow River that forms Longyang Gorge, providing a good vertical profile for thermochronological investigation exhumation. In this paper, we reconstruct cooling and history Eastern using apatite fission-track(AFT) (UTh)/He(AHe) dating on basement rocks. fission-track data display marked age-elevation trend from Early Cretaceous (114–122 Ma) ages at bottom canyon to Early-Middle Jurassic (165–180 top. Mean (UTh)/He are mainly (97–128 with one Eocene outlier (42 Ma). Combined fission track lengths, Dpar values thermal modeling results, these indicate study area resided above closure temperature AFT AHe until Cretaceous. Rapid occurred during early Cenozoic likely driven Lhasa Indian blocks collision southern margin Asian continent. Nonetheless, since then was limited less than few kilometers area. regional geological studies, analysis demonstrates that, Mesozoic, intense simultaneously along margins Shan. Hence, suggest geomorphic framework northeast established Cretaceous-early Cenozoic.