A distinctive Eocene Asian monsoon and modern biodiversity resulted from the rise of eastern Tibet

• DOI: 10.1016/j.scib.2022.10.006
• Publication Date: 2022-10-08T01:57:58Z
• Authors: Songlin He; Lin Ding; Zhongyu Xiong; Robert A. Spicer; Alex Farnsworth; Paul J. Valdes; Chao Wang; Fulong Cai; Houqi Wang; Yong Sun; Deng Zeng; Jing Xie; Yahui Yue; Chenyuan Zhao; Peiping Song; Chen Wu
• Keywords: East Asian Monsoon; Tropical monsoon climate; Global cooling

The uplift of eastern Tibet, Asian monsoon development and the evolution globally significant biodiversity are all linked, but in obscure ways. Sedimentology, geochronology, clumped isotope thermometry, fossil leaf-derived numerical climate data from Relu Basin, show at ∼50-45 Ma basin was a hot (mean annual air temperature, MAAT, ∼27 °C) dry desert low-elevation 0.6 ± km. Rapid rise to 2.0 0.9 km 45-42 2.9 42-40 Ma, with MAATs ∼20 ∼16 °C, respectively, accompanied seasonally varying increased precipitation > 1500 mm. From ∼39 34 attained 3.5 1.0 km, near its present-day elevation (∼3.7 km), MAAT cooled ∼6 °C. Numerically-modelled strength significantly when this Eocene Tibet incorporated. simulation/proxy congruence points distinctive monsoon, quite unlike that seen today, it featured bimodal winter-wet regime, enhanced modernisation across Asia. Paleogene Asia evolved under continually modifying influence, modern system being unique present product long gradual context an ever-changing Earth system.