Chronological constraints on multi-staged rapid cooling of the Tianshan Mountains inferred from apatite fission track analysis of modern river sands

The extreme modern elevation of the Tianshan Mountains reflects the Cenozoic deformation. Apatite Fission Track (AFT) chronometry is widely used to study the latest cooling stages caused by tectonic process or by exhumation in the uppermost crust. However, uncertainties remain over timing constraints on thermal history of the Tianshan Mountains since the Cenozoic though a great mount of dating work had been done in this area. To address this issue, modern river sands from the drainage basin on the piedmont of the Tianshan Mountains were sampled to integrate regional information. Single grains were dated with the AFT method, and then different grain-age components were identified to provide thermochronological constraints of their sources. Combined with discussion of previous dataset, our results show the multi-staged rapid cooling cluster at 46-32, 25-24, 19-13, 8-6, and ∼3 Ma, respectively. We interpreted these cooling events as a result of interplays between the Cenozoic tectonic uplift of the mountains and regional climate change.