Zhao Yan, Tzedakis Polychronis C, Li Quan, Qin Feng, Cui Qiaoyu, Liang Chen, Birks H John B, Liu Yaoliang, Zhang Zhiyong, Ge Junyi, Zhao Hui, Felde Vivian A, Deng Chenglong, Cai Maotang, Li Huan, Ren Weihe, Wei Haicheng, Yang Hanfei, Zhang Jiawu, Yu Zicheng, Guo Zhengtang
Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Adv. 2020 May 6;6(19):eaay6193. doi: 10.1126/sciadv.aay6193. eCollection 2020 May.
The Tibetan Plateau exerts a major influence on Asian climate, but its long-term environmental history remains largely unknown. We present a detailed record of vegetation and climate changes over the past 1.74 million years in a lake sediment core from the Zoige Basin, eastern Tibetan Plateau. Results show three intervals with different orbital- and millennial-scale features superimposed on a stepwise long-term cooling trend. The interval of 1.74-1.54 million years ago is characterized by an insolation-dominated mode with strong ~20,000-year cyclicity and quasi-absent millennial-scale signal. The interval of 1.54-0.62 million years ago represents a transitional insolation-ice mode marked by ~20,000- and ~40,000-year cycles, with superimposed millennial-scale oscillations. The past 620,000 years are characterized by an ice-driven mode with 100,000-year cyclicity and less frequent millennial-scale variability. A pronounced transition occurred 620,000 years ago, as glacial cycles intensified. These new findings reveal how the interaction of low-latitude insolation and high-latitude ice-volume forcing shaped the evolution of the Tibetan Plateau climate.
青藏高原对亚洲气候有着重大影响，但其长期环境历史在很大程度上仍不为人知。我们展示了青藏高原东部若尔盖盆地一个湖泊沉积岩芯中过去174万年的植被和气候变化的详细记录。结果显示，在长期降温趋势呈阶梯状的基础上，有三个具有不同轨道尺度和千年尺度特征的时期。174万至154万年前的时期以日照主导模式为特征，具有强烈的约2万年周期性且几乎没有千年尺度信号。154万至62万年前的时期代表了一个过渡性的日照-冰模式，以约2万年和约4万年的周期为特征，并叠加有千年尺度振荡。过去62万年以冰驱动模式为特征，具有10万年周期性且千年尺度变化频率较低。62万年前发生了明显转变，冰川周期加剧。这些新发现揭示了低纬度日照与高纬度冰量强迫的相互作用如何塑造了青藏高原气候的演变。
