The uplift of eastern Tibet,Asian monsoon development and the evolution of globally significant Asian biodiversity are all linked,but in obscure ways.Sedimentology,geochronology,clumped isotope thermometry,and fossil ...The uplift of eastern Tibet,Asian monsoon development and the evolution of globally significant Asian biodiversity are all linked,but in obscure ways.Sedimentology,geochronology,clumped isotope thermometry,and fossil leaf-derived numerical climate data from the Relu Basin,eastern Tibet,show at~50–45 Ma the basin was a hot(mean annual air temperature,MAAT,~27℃)dry desert at a low-elevation of 0.6±0.6 km.Rapid basin rise to 2.0±0.9 km at 45–42 Ma and to 2.9±0.9 km at 42–40 Ma,with MAATs of~20 and~16℃,respectively,accompanied seasonally varying increased annual precipitation to>1500 mm.From~39 to 34 Ma,the basin attained 3.5±1.0 km,near its present-day elevation(~3.7 km),and MAAT cooled to~6℃.Numerically-modelled Asian monsoon strength increased significantly when this Eocene uplift of eastern Tibet was incorporated.The simulation/proxy congruence points to a distinctive Eocene Asian monsoon,quite unlike that seen today,in that it featured bimodal precipitation and a winter-wet regime,and this enhanced biodiversity modernisation across eastern Asia.The Paleogene biodiversity of Asia evolved under a continually modifying monsoon influence,with the modern Asian monsoon system being unique to the present and a product of a long gradual development in the context of an ever-changing Earth system.展开更多
The growth of the Qinghai-Tibetan Plateau(QTP)during the Cenozoic drove dramatic climate and environmental change in this region.However,there has been limited comprehensive research into evolution of climate during t...The growth of the Qinghai-Tibetan Plateau(QTP)during the Cenozoic drove dramatic climate and environmental change in this region.However,there has been limited comprehensive research into evolution of climate during this interval.Here we present a quantitative reconstruction using Bioclimatic Analysis(BA)and Joint Probability Density Functions(JPDFs)based on data available for 48 fossil floras,including macrofossils and palynological fossils collected in the QTP area from the Paleogene to Neogene(66–2.58 Ma).Both methods indicate that there was an overall decline in temperature and precipitation.Paleoclimatic simulations using Hadley Centre Coupled Model version3(HadCM3)show that the most prominent climate change was very likely driven by QTP orographic evolution from the late Eocene,which was accompanied by a shift in temperature from a latitudinal distribution to a topographically controlled pattern.In addition,with the growth of the QTP,temperature and precipitation decreased gradually in the northeastern part of the plateau.Different sources of evidence,including plant fossil records,climate simulations and other proxies,indicate that the topographic evolution of the QTP and other geological events,in conjunction with global cooling,may have been the main factors driving climate change in this region.This research can provide insights into Cenozoic environmental change and ecosystem evolution.展开更多
基金supported by the National Natural Science Foundation of China Basic Science Center for Tibetan Plateau Earth System(41988101)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0708)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20070301)the National Natural Science Foundation of China-Natural Environment Research Council of the United Kingdom Joint Research Program(41661134049 and NE/P013805/1)the National Natural Science Foundation of China(41941016)。
文摘The uplift of eastern Tibet,Asian monsoon development and the evolution of globally significant Asian biodiversity are all linked,but in obscure ways.Sedimentology,geochronology,clumped isotope thermometry,and fossil leaf-derived numerical climate data from the Relu Basin,eastern Tibet,show at~50–45 Ma the basin was a hot(mean annual air temperature,MAAT,~27℃)dry desert at a low-elevation of 0.6±0.6 km.Rapid basin rise to 2.0±0.9 km at 45–42 Ma and to 2.9±0.9 km at 42–40 Ma,with MAATs of~20 and~16℃,respectively,accompanied seasonally varying increased annual precipitation to>1500 mm.From~39 to 34 Ma,the basin attained 3.5±1.0 km,near its present-day elevation(~3.7 km),and MAAT cooled to~6℃.Numerically-modelled Asian monsoon strength increased significantly when this Eocene uplift of eastern Tibet was incorporated.The simulation/proxy congruence points to a distinctive Eocene Asian monsoon,quite unlike that seen today,in that it featured bimodal precipitation and a winter-wet regime,and this enhanced biodiversity modernisation across eastern Asia.The Paleogene biodiversity of Asia evolved under a continually modifying monsoon influence,with the modern Asian monsoon system being unique to the present and a product of a long gradual development in the context of an ever-changing Earth system.
基金supported by the Basic Science Center for Tibetan Plateau Earth System(Grant No.41988101)the Yunnan Province Natural Science Foundation(Grant No.2019FB061)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,Grant No.2019QZKK0705)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB26000000)the National Natural Science Foundation of China(Grant No.41772026)。
文摘The growth of the Qinghai-Tibetan Plateau(QTP)during the Cenozoic drove dramatic climate and environmental change in this region.However,there has been limited comprehensive research into evolution of climate during this interval.Here we present a quantitative reconstruction using Bioclimatic Analysis(BA)and Joint Probability Density Functions(JPDFs)based on data available for 48 fossil floras,including macrofossils and palynological fossils collected in the QTP area from the Paleogene to Neogene(66–2.58 Ma).Both methods indicate that there was an overall decline in temperature and precipitation.Paleoclimatic simulations using Hadley Centre Coupled Model version3(HadCM3)show that the most prominent climate change was very likely driven by QTP orographic evolution from the late Eocene,which was accompanied by a shift in temperature from a latitudinal distribution to a topographically controlled pattern.In addition,with the growth of the QTP,temperature and precipitation decreased gradually in the northeastern part of the plateau.Different sources of evidence,including plant fossil records,climate simulations and other proxies,indicate that the topographic evolution of the QTP and other geological events,in conjunction with global cooling,may have been the main factors driving climate change in this region.This research can provide insights into Cenozoic environmental change and ecosystem evolution.
