EGU2020-22396
https://doi.org/10.5194/egusphere-egu2020-22396
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

A Late Miocene terrestrial temperature history for the northeastern Tibetan Plateau’s period of tectonic expansion

Yan Bai1, Chihao Chen1,2,3, Xiaomin Fang1,2,3, Haichao Guo2,3, Qaingquan Meng4, and Weilin Zhang1,2
Yan Bai et al.
  • 1CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences (CAS), Beijing 100101, China
  • 2CAS Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China
  • 3University of Chinese Academy of Sciences, Beijing 100049, China
  • 4School of Earth Sciences and Key Laboratory of Western China’s Mineral Resources of Gansu Province, Lanzhou University, Lanzhou 730000, China

During the Late Miocene, the climate patterns and ecosystems of continental land masses experienced crucial transitions, but whether the principal driver was regional tectonic forcing or a decline in CO2 concentrations remains debated. Terrestrial paleotemperature records from tectonically active regions can conserve both paleoaltitudinal and global temperature changes which have occurred as a result of fluctuations in the levels of CO2. However, high-quality quantitative data remain scarce, due to the lack of terrestrial paleotemperature reconstruction tools and well-dated continuous stratigraphic sequences. Based on a continuous sedimentary sequence with high precision dating from ~54-4.8 Ma in Xining Basin, northeastern Tibetan Plateau established, and evaluation of the potentiality of the branched glycerol dialkyl glycerol tetraethers (brGDGTs) in paleotemperature/paleoelevation reconstruction in Tibetan Plateau by our group, we present a terrestrial paleotemperature record spanning ~12.7-5.2 Ma based on tetraether lipids extracted from the northeastern Tibetan Plateau. Our results reveal a sharp cooling (~8°C) during ~10.5-8 Ma, asynchronous with minor fluctuations in global sea temperatures, suggesting a rapid tectonic uplift of ~1 km in extent. This event appears consistent with the simultaneous aridification and transitions of ecosystems experienced in adjacent regions. Moreover, the amplitude of the cooling over land is less than that which occurred over the ocean during the CO2-dominated Late Miocene cooling event (~7-5.4 Ma). We therefore concluded that tectonic forcing, rather than a decline in CO2 levels, most likely dominated continental climate patterns and ecosystem transitions during the Late Miocene.

How to cite: Bai, Y., Chen, C., Fang, X., Guo, H., Meng, Q., and Zhang, W.: A Late Miocene terrestrial temperature history for the northeastern Tibetan Plateau’s period of tectonic expansion, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22396, https://doi.org/10.5194/egusphere-egu2020-22396, 2020

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