Copy the page URI to the clipboard
Su, Tao; Spicer, Robert A.; Wu, Fei-Xiang; Farnsworth, Alexander; Huang, Jian; Del Rio, Cédric; Deng, Tao; Ding, Lin and
(2020).
DOI: https://doi.org/10.1073/pnas.2012647117
Abstract
Tibet’s ancient topography and its role in climatic and biotic evo- lution remain speculative due to a paucity of quantitative surface- height measurements through time and space, and sparse fossil records. However, newly discovered fossils from a present eleva- tion of ∼4,850 m in central Tibet improve substantially our knowl- edge of the ancient Tibetan environment. The 70 plant fossil taxa so far recovered include the first occurrences of several modern Asian lineages and represent a Middle Eocene (∼47 Mya) humid subtropical ecosystem. The fossils not only record the diverse com- position of the ancient Tibetan biota, but also allow us to constrain the Middle Eocene land surface height in central Tibet to ∼1,500 ± 900 m, and quantify the prevailing thermal and hydrological re- gime. This “Shangri-La”–like ecosystem experienced monsoon sea- sonality with a mean annual temperature of ∼19 °C, and frosts were rare. It contained few Gondwanan taxa, yet was composi- tionally similar to contemporaneous floras in both North America and Europe. Our discovery quantifies a key part of Tibetan Paleo- gene topography and climate, and highlights the importance of Tibet in regard to the origin of modern Asian plant species and the evolution of global biodiversity.