Late Oligocene mountain building of the East Kunlun Shan in northeastern Tibet: Impact on the Cenozoic climate evolution in East Asia

• Published in: Global and planetary change Vol. 224; p. 104114
• Main Authors: Li, Chaopeng, Zheng, Dewen, Yu, Jingxing, Zhou, Renjie, Wang, Yizhou, Pang, Jianzhang, Wang, Ying, Hao, Yuqi, Xu, Yi-Gang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2023
• Subjects: Apatite (U[sbnd]Th)/He; Climate reorganization; East Kunlun Shan; Northeastern Tibet; Northeastern Tibet; Apatite (UTh)/He; Climate reorganization; East Kunlun Shan
• ISSN: 0921-8181; 1872-6364
• DOI: 10.1016/j.gloplacha.2023.104114

The role of northern Tibet in the Cenozoic climate evolution in East Asia remains controversial owing to a lack of constraints on the timing and pattern of mountain building. The East Kunlun Shan (EKLS) defines the geomorphological boundary of the northeastern Tibetan Plateau. We employed apatite (UTh)/He thermochronology to analyze the exhumation history and pattern across the EKLS. In this study, we presented 28 mean apatite (UTh)/He ages of bedrock, including seven previously published ages. Observed ages decrease with the decreased distance from the Kunlun strike-slip fault (34.0 to 20.4 Ma). Age-elevation relationships and thermal modeling demonstrate that exhumation rates in the EKLS and in restraining bends along the Kunlun strike-slip fault increased by a factor of 5–10, reaching ∼200 m/Myr at ∼26 Ma. These exhumation patterns support the idea that mountain building of the EKLS initiated in the Late Oligocene through northward tilting around the same time with strike-slip motion along the Kunlun fault. When combined with existing geological data, our findings suggest that the northern margin of high Tibet expanded from Tanggula Shan to EKLS-West Qinling during the Late Oligocene to Early Miocene. This period coincides with the initial accumulation of loess at the front of northern Tibet and the northward expansion of the monsoon region in adjacent East China. Therefore, our work supports the notion that the northward growth of Tibet may have played a role in the Late Oligocene-Early Miocene climate reorganization in East Asia. •Accelerated exhumation at ∼26 Ma in the East Kunlun Shan•Late Oligocene initial uplift related to the tilting of the entire East Kunlun Shan•Coincidence between northward growth of Tibet and climate changes in East Asia