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中国沙漠 ›› 1998, Vol. 18 ›› Issue (2): 105-110.

• 研究论文 • 上一篇    下一篇

130ka B.P.前后黄土高原东部地区的气候侵蚀事件

周杰1,4, 张信宝1,2, 陈惠忠1,3, 孙东怀1, 薛祥煦4   

  1. 1. 中国科学院黄土与第四纪地质国家重点实验室 西安 710054;
    2. 中国科学院水利部成都山地灾害与环境研究所 成都 610041;
    3. 中国科学院兰州沙漠研究所 兰州 730000;
    4. 西北大学地质系 西安 710069
  • 收稿日期:1997-10-25 修回日期:1998-01-05 出版日期:1998-06-20 发布日期:1998-06-20
  • 作者简介:周杰,男,1964年生,副研究员,在职博士生。现从事第四纪地质和全球变化研究。
  • 基金资助:
    中国科学院"九五"重大项目(KZ951-A1-402)

CLIMATIC EROSION EVENT OCCURRED IN THE EASTERN LOESS PLATEAU AT ABOUT 130 ka B. P.

ZHOU Jie1,4, ZHANG Xin-bao1,2, CHEN Hui-zhong1,3, SUN Dong-huai1, XUE Xiang-xi4   

  1. 1. State Key Laboratory of Loess and Quaternary Geology, Chinese Academy of Sciences, Xi'an 710054;
    2. Institu te of Mountain Haz ards and Environmen t, Ch inese Aca demy of Sciences, Cheng du 610041;
    3. Institue of Deser t Reserch, Chinese Academy of Sciences, Lanzhou 730000;
    4. Department of Geology, North-Western University, Xi'an 710069
  • Received:1997-10-25 Revised:1998-01-05 Online:1998-06-20 Published:1998-06-20

摘要: 通过黄土高原塬区、梁峁区和断陷谷区典型沟谷的阶地堆积、侵蚀面及其与之相邻的黄土-古土壤地层序列研究,并结合古气候特征分析,提出倒数第二次冰期冬季风向末次间冰期夏季风过渡期黄土高原东部地区发生了强烈的气候侵蚀事件。沉积物特征研究和古气候复原结果表明,此次侵蚀是一次以暴雨为主要动力的快速侵蚀事件。

关键词: 黄土高原, 季风, 气候过渡期, 侵蚀事件

Abstract: By the study on the terrace deposits, erosional surface and the neighbouring loess~paleosol sequences from different erosion profiles located in flat-land and hill-land as well as valley rigions of Loess Plateau, and linking to the analysis of proxy indices of paleo-climate, three results are concluded (1) The well developed T3 terraces of the gullies in flat-land, hill-land and valley rigions of eastern Loess Plateau, and their identical deposit features which include sand-gravel, subclay and fluvial loess layers indicate that they are obviously the relevant sediments during the strong erosion period. Comparing stratigraphy with TL dating results, it can be determined that Si paleosols formed in the interglacial period draped over the above gully terraces- This implied that the erosion event occurred at about 130 ka B. P. before the S1 pal eosols dev el-o ped. (2) The analysis of climatic proxy indices such as magnetic-susceptibility, δ13C and variability of magnetic-susceptibility revealled a greater climatic gradient or greater precipitation variability at about 130 ka B. P., which showed, on one hand, the precipitation increased sharply, on the other hand, the precipitation contribution with time was rather uneven. These provided a favourable driving condition for large scale land surface erosion. The δ13C value increasing smoothly, and magnetic-susceptibility rising sharply indicated that, even though precipitation suddenly increased, the vegetation was not recovered completely yet. These provided profitable land surface environmental condition for the large scale erosion. Due to the above two factors, the eastern Loess Plateau occurred a violent climatic erosion event at about 130 ka B. P. before the S1 paleosols developed. (3) The deposits of T3 terraces were sand mixed with gravel. The too bad sorting implied that this erosion event was probably drived by high intensity rain storms.

Key words: Loess Plateau, Monsoon, Climatic change period, Erosion event

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