image: (a) Global CO2 concentration was estimated from the multiproxy dataset compiled by Tierney et al. (2020), the CO2 error envelopes represent 1σ uncertainties; (b) Global mean temperature was estimated from benthic δ18O by Westerhold et al.(2020), and (c) Simulated mean values of altitude on the QTP view more
Credit: ©Science China Press
This study is led by the Paleoecology Research Group (PRG) of the Xishuangbanna Tropical Botanical Garden (XTBG), Chinese Academy of Sciences (CAS).
The PRG is the main force of the paleontological scientific expedition team in the Second Tibetan Plateau Scientific Expedition and Research (STEP), dedicated to the study of Cenozoic paleobotany and paleoenvironmental changes. Plant fossils are direct and reliable indicators of environmental conditions, and hence can be used to reconstruct the paleoenvironment and paleoclimate. The ongoing STEP has led to outstanding achievements in paleobotany on the Tibetan Plateau, a number of fossil floras with well constrained geological ages were discovered and reported. The researchers collected macrofossils and palynological fossils from the Paleogene to Neogene (66–2.58 Ma) available for 48 fossil floras in this area, and also presented a quantitative climatic reconstruction using Bioclimatic Analysis (BA) and Joint Probability Density Functions (JPDFs) based on this data.
The research team cooperated with Prof. Paul J. Valdes and Dr. Alex Farnsworth, carried out paleoclimate simulations in different geological ages based on the Hadley Centre Coupled Model version3 (HadCM3) from the University of Bristol in the UK. The quantitative reconstructions using fossils and numerical simulations were then compared with each other to explore the climate evolution during the Cenozoic.
Integrating different sources of evidence, including plant fossil records, climate simulations and other proxies, the researchers concluded that the climate shows an overall cooling trend on the Tibetan Plateau under the influence of global climate change and the growth of the plateau.
“The dramatic climate change was very likely driven by Tibetan uplift during the late Eocene (around 35 Ma), the temperature was shifted from a latitudinal distribution pattern to a topographically controlled pattern.” Jiagang Zhao, the first author, said.
In addition, the numerical simulations also show temperature and precipitation decreased gradually in the northeastern part of the plateau.
This study can provide a crucial basis for understanding the link between the growth of the Tibetan Plateau and climate change, as well as vegetation and ecological environment change.
For more details, please refer to the paper “The Paleogene to Neogene climate evolution and driving factors on the Qinghai-Tibetan Plateau”, to be published in Science China Earth Sciences.
Journal
Science China Earth Sciences