JOPC ›› 2022, Vol. 24 ›› Issue (3): 599-610. doi: 10.7605/gdlxb.2022.03.050

• QUATERNARY PALAEOGEOGRAPHY AND SEDIMENTOLOGY • Previous Articles    

Comparison of correlation between magnetic susceptibility and grain size for lacustrine sediments in eastern Tibetan Plateau and loess deposits in Chinese Loess Plateau

Shi Wei1,2, Jiang Han-Chao1   

  1. 1 State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China;
    2 College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China
  • Received:2020-06-12 Revised:2022-03-30 Online:2022-06-01 Published:2022-05-30
  • Contact: Jiang Han-Chao,born in 1973,is a professor and doctoral supervisor. He is engaged in research of Cenozoic geological and environmental events,evolution of Cenozoic palynoflora,and paleoearthquake events recorded by lacustrine sediments. E-mail: hcjiang@ies.ac.cn.
  • About author:Shi Wei,born in 1989,is a Ph.D. candidate in Institute of Geology,China Earthquake Administration. He is engaged in research of paleoearthquake events recorded by lacustrine sediments. E-mail: jzxshiwei@163.com.
  • Supported by:
    Co-funded by the National Key Research and Development Program of China (No.2017YFC1501000),and the Key Projects of Director's Fund, China Earthquake Administration (No. IGCEA1906)

青藏高原东缘湖相沉积和黄土高原黄土沉积磁化率与粒度相关性对比*

时伟1,2, 蒋汉朝1   

  1. 1 中国地震局地质研究所地震动力学国家重点实验室,北京 100029;
    2 中国科学院大学地球与行星科学学院,北京 100049
  • 通讯作者: 蒋汉朝,男,1973年生,研究员,博士生导师,主要从事新生代地质环境事件与孢粉植物群研究以及湖沼地震学研究。E-mail: hcjiang@ies.ac.cn。
  • 作者简介:时伟,男,1989年生,博士研究生,主要从事湖相沉积古地震研究。E-mail: jzxshiwei@163.com。
  • 基金资助:
    *国家重点基础研究发展计划项目(编号: 2017YFC1501000)和中国地震局所长基金重点项目(编号: IGCEA1906)联合资助

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Abstract: To explore the correlation between magnetic susceptibility(SUS)and grain size of the dust deposits from the tectonically stable and active regions and its implications for environmental events,the grain size and SUS records from the Lantian loess sediments-paleosol of the Chinese Loess Plateau(CLP)were analyzed and compared with that of the lacustrine sediments from the eastern margin of the Tibetan Plateau(TP). Results indicate that the SUS of the loess sediments has the strongest positive correlation with the loess sediments of 2~10 μm grain size in the Chinese Loess Plateau(CLP) and strongest negative in the Tibetan Plateau,respectively,indicating that the 2~10 μm grain size of dust sediments were continuous and stable,which were deposited in the background of the arid to semi-arid regions in the CLP and TP and even in Asia. On the other hand,SUS showed the strongest positive correlation with the 32~63 μm grain size of the loess sediments in the Tibetan Plateau and strongest negative in the Chinese Loess Plateau(CLP),respectively,indicating that the 32~63 μm grain size of the dust sediments were the sensitive indicator not only for the dust storms in the CLP, but also for the seismic events in the eastern margin of the TP. The correlation between SUS and grain size during the beginning period of the seismic event in the eastern part of TP was higher than that of the ending period,indicating that the seismic event brings the fresh sediments in the study area and then decreases due to the gradual recovery of the landscape. The correlation between SUS and grain size is also influenced by the local provenance.

Key words: correlation of SUS and grain size, loess sediments, lacustrine sediments, eastern margin of the Tibetan Plateau, dust storm event, seismic event

摘要： 为探讨构造稳定地区(如黄土高原)和构造活跃地区(如青藏高原东缘)粉尘沉积物中磁化率(SUS)与粒度的相关性及其对环境事件的指示意义,本次研究分析了黄土高原蓝田剖面黄土—古土壤样品和青藏高原东缘湖相沉积样品的粒度和磁化率记录。黄土高原黄土—古土壤沉积SUS与2~10 μm粒度组分最强正相关,青藏高原东缘湖相沉积的SUS与2~10 μm粒度组分最强负相关,反映2~10 μm粒度组分为黄土高原和青藏高原乃至亚洲干旱—半干旱地区连续稳定敏感的背景沉积组分。黄土高原黄土—古土壤沉积的SUS与32~63 μm粒度组分最强负相关,青藏高原东缘湖相沉积的SUS与32~63 μm粒度组分最强正相关,反映32~63 μm粒度组分不仅是黄土高原尘暴事件沉积的敏感指标,也是青藏高原东缘湖相沉积记录的地震事件敏感指标。SUS与粒度组分的相关性在青藏高原东缘地区地震事件层开始部分高于结束部分,也较好地反映地震事件为研究区添加新鲜沉积物后随地形地貌恢复逐步减少的过程。SUS与粒度组分相关性也受当地物源的影响。

关键词: 磁化率与粒度相关性, 黄土沉积, 湖相沉积, 青藏高原东缘, 尘暴事件, 地震事件

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