Evidence from zircon and apatite thermochronology provides evidence for the tectonic-thermal evolution and denudational processes in Dulan, Eastern Kunlun Mountains, China

Abstract

Since the Middle Jurassic, the East Kunlun orogenic belt in China has undergone significant denudation. This region offers crucial insights into the tectonic processes that have shaped the Tibetan Plateau. Moreover, the region boasts abundant mineral resources. This study uses techniques, such as zircon and apatite fission track (ZFT&AFT) analyses as well as citing several apatite (U-Th)-He (AHe) ages and FT ages data from the study areas, to unravel the tectonic-thermal evolution and denudation processes. The results reveal ZFT ages spanning from 167 ± 5 to 92 ± 4 Ma, and AFT ages spanning from 116 ± 6 to 64 ± 4 Ma. Based on the AFT, ZFT, and AHe data, this paper constructed a tectonic-thermal history model. In the first stage (ca. 170–120 Ma), rapid cooling at 2.00 ℃/Ma and denudation of 2.85 km occurred. The second stage (ca. 120–20 Ma) showed cooling rates of 0.60 ℃/Ma and denudation of 1.70 km. In the third stage (ca. 20–0 Ma), rapid cooling with rates of 1.50 ℃/Ma and denudation of 0.86 km were speculated. The first stage indicates the closure of the Paleo-Tethys Ocean in the Middle Jurassic, with the collision of the Lhasa and Qiangtang blocks with Eurasia along the Bangong-Nujiang suture zone in the Cretaceous. The second stage is mainly related to the northward subduction of the Neo-Tethys Ocean and the far-flung effects of the India-Eurasia collision. The uplift of the Tibetan plateau due to the Himalayan orogeny likely contributed to the third stage. The denuded thickness in the study area since 170 Ma is 5.41 km.