Grain-size Age Model in Reconstructing Orbital-and Suborbital-scale Climate Changes on the Northeastern Tibetan Plateau Since the Late Glacial |
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作者姓名: | LI Yuan ZHAO Hui |
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作者单位: | 1.Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China;2.Key Laboratory of Western China’s Environmental Systems (MOE), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China |
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基金项目: | This research was supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDA20090000);the National Natural Science Foundation of China (Grants 41901103);the Foundation for Excellent Youth Scholars of "Northwest Institute of Eco-Environment and Resources", CAS |
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摘 要: | Reconstructions of past climatic changes on the northeastern Tibetan Plateau(NETP) can provide insights into the Asian summer monsoon(ASM) variability. However, the regional climate changes on both orbital and suborbital time scales since the late Glacial remain controversial. Here we present the results of high-resolution geochemical and grain-size analyses of a sediment core from Genggahai Lake, a small, shallow lake in this area. Changes of the accumulation rate of the core sediments show a s...
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关 键 词: | climate change lake sediment grain-size age model MONSOON HOLOCENE China |
收稿时间: | 2020/3/1 0:00:00 |
修稿时间: | 2020/4/2 0:00:00 |
Grain‐size Age Model in Reconstructing Orbital‐ and Suborbital‐scale Climate Changes on the Northeastern Tibetan Plateau Since the Late Glacial |
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Authors: | LI Yuan ZHAO Hui |
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Abstract: | Reconstructions of past climatic changes on the northeastern Tibetan Plateau (NETP) can provide insights into the Asian summer monsoon (ASM) variability. However, the regional climate changes on both orbital and suborbital time scales since the late Glacial remain controversial. Here we present the results of high‐resolution geochemical and grain‐size analyses of a sediment core from Genggahai Lake, a small, shallow lake in this area. Changes of the accumulation rate of the core sediments show a similar trend with variations of the coarse fraction. Accordingly, the chronological framework is constructed using a grain‐size age model. In addition, the histories of chemical weathering and aeolian activity since the late Glacial are reconstructed based on the Al/Ti ratios and coarse fractions, respectively. The results suggest that an enhanced chemical weathering and a weakened aeolian activity occurred on the NETP under a warmer, wetter climate during the early to mid‐Holocene (11.3–6.3 ka cal BP), compared with the late Glacial (17.1–11.3 ka cal BP) and the late Holocene (6.3 ka cal BP to present), which responded mainly to the strengthened ASM on orbital time scale. In addition, the synchronous occurrences of weakened chemical weathering, low lake level and intense aeolian activity on suborbital time scale reflect several episodes of weakened ASM. Furthermore, these episodes largely coincide with the centennial‐ to millennial‐scale cold events in the North Atlantic, which demonstrates the close connection between the ASM and the cooling at high latitudes. |
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Keywords: | climate change lake sediment grain-size age model monsoon Holocene China |
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