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中国沙漠 ›› 2022, Vol. 42 ›› Issue (4): 253-263.DOI: 10.7522/j.issn.1000-694X.2022.00019

• • 上一篇    

腾格里沙漠西南缘土门剖面微量元素记录的MIS3高分辨率季风环境变化

陈敏1(), 李保生1,2(), 王丰年3, 牛东风4, 温小浩1, 舒培仙2, 司月君5, 杨庆江6, 王晨7   

  1. 1.华南师范大学 地理科学学院,广东 广州 510631
    2.中国科学院地球环境研究所 黄土与第四纪地质国家重点实验室,陕西 西安 710061
    3.惠州学院 地理与旅游学院,广东 惠州 516007
    4.岭南师范学院 地理科学学院,广东 湛江 524048
    5.南宁师范大学 地理科学与规划学院,广西 南宁 530001
    6.中国科学院古脊椎动物与古人类研究所,北京 100044
    7.西藏大学 理学院,西藏 拉萨 850000
  • 收稿日期:2021-11-17 修回日期:2022-02-18 出版日期:2022-07-20 发布日期:2022-08-29
  • 通讯作者: 李保生
  • 作者简介:李保生(E-mail: libsh@scnu.edu.cn
    陈敏(1991—),女,四川眉山人,实验员,主要从事第四纪环境与演变研究。E-mail: 20175014@m.scnu.edu.cn
  • 基金资助:
    国家自然科学基金项目(41290250);国家重点基础研究发展计划项目(2013CB955903)

High-resolution monsoonal environment change in MIS3 based on trace elements in the Tumen Section on the southweest edge of Tegger Desert

Min Chen1(), Baosheng Li1,2(), Fengnian Wang3, Dongfeng Niu4, Xiaohao Wen1, Peixian Shu2, Yuejun Si5, Qinjiang Yang6, Chen Wang7   

  1. 1.School of Geography,South China Normal University,Guangzhou 510631,China
    2.State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi'an 710061,China
    3.School of Geography and Tourism,Huizhou University,Huizhou 516007,Guangdong,China
    4.School of Geographical Sciences,Lingnan Normal University,Zhanjiang 524048,Guangdong,China
    5.School of Geography and Planning,Nanning Normal University,Nanning 530001,China
    6.Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences,Beijing 100044,China
    7.Faculty of Science,Tibet University,Lhasa 850000,China
  • Received:2021-11-17 Revised:2022-02-18 Online:2022-07-20 Published:2022-08-29
  • Contact: Baosheng Li

摘要:

对位于腾格里沙漠西南边缘的土门剖面中时代为MIS3的TMS3层段进行序列分析与14C和释光测年,并在此基础上对沉积层进行系统的微量元素地球化学分析。结果表明:TMS3是由沙丘砂与其他5类沉积相(黄土状亚砂土、砂黄土、湖沼相、水成黄土和古土壤)构成的相互叠覆的沉积,形成14.5个“沉积旋回”。TMS3微量元素Mn、P、Sr、Rb、V、Zn、Cr、Ni、Cu和Nb在沙丘砂中含量低,在其他5类沉积相中含量高;Rb/Sr比值则呈现相反的变化趋势。在剖面上,随着沙丘砂与这5类沉积相的交替,元素含量、Rb/Sr比值表现出明显的峰(高值)谷(低值)波动,并形成基本上与沉积旋回数量一致的“元素旋回”——ECY1—ECY14.5。该层段14.5个元素旋回揭示了相同数量的腾格里沙漠东亚冬夏季风演变的“旋回”——MCY1—14.5,包括14次冬季风事件和15次夏季风事件,每个季风旋回的持续时间平均约2.48 ka;TMS3元素记录的15次夏季风事件与GRIP冰芯和葫芦洞石笋MIS3-δ18O曲线的间冰阶具有相同的发生次数,也与邻近的古浪黄土MIS3中的间冰阶可以进行很好的对比。土门剖面TMS3的地球化学迁聚行为和沉积相,在一定意义上诠释了MIS3北半球冷暖波动——腾格里沙漠东亚冬夏季风环境变化的响应过程。

关键词: MIS3, 腾格里沙漠, 微量元素, Rb/Sr比值, 东亚季风, 千年尺度气候变率

Abstract:

The TMS3 segment in the Tumen section, equivalent to the MIS3, is located at the southwest margin of the Tengger Desert. Based on the sedimentary sequences analysis and 14C and OSL dating ages, geochemical trace elements were analyzed. The study shows that TMS3 segment consists of interbedding stratigraphic sequences of dune sands with loess-like subsoil, sandy loess, lacustrine facies, alluvial loess, or paleosols, forming 14.5 sedimentary cycles. The contents of trace elements Mn, P, Sr, Rb, V, Zn, Cr, Ni, Cu, Nb are low in dune sands, but high in other 5 sedimentary facies in the TMS3, and the ratios of Rb/Sr display reversed tendency, which show obvious element contents and Rb/Sr ratios alternation with low values and high peaks between dune sands and other 5 sedimentary facies, indicating 14.5 elemental cycles ECY1-ECY14.5, which are consistent with sedimentary cycles. It suggests that 14.5 element cycles in the TMS3 represent 14.5 monsoonal cycles (MCY1—14.5) in the alternation of East Asian winter and summer monsoons during the MIS3, including 14 times of winter monsoons and 15 times of summer monsoons, and average time duration of each monsoon cycle is 2.48ka. 15 summer monsoon events recorded by trace elements in the TMS3 correspond well to the stadials revealed in the ice core of the GRIP and by δ18O in Huludong Cave, as well as those found in the adjacent area in the loess in Gulang during the MIS3. The geochemical migration and accumulation and sedimentary facies in the TMS3, to some extent, illustrate East Asian winter and summer monsoon environment changes in the Tengger Desert in response to the cold-warm climate fluctuations in the Northern Hemisphere during the MIS3.

Key words: MIS3, Tengger Desert, trace elements, Rb/Sr ratios, East Asian monsoon, Millennium scale climate variability

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