地球物理学进展 ›› 2019, Vol. 34 ›› Issue (1): 42-47.doi: 10.6038/pg2019CC0030

• 固体地球物理及空间物理学(大气、行星、地球动力学、重磁电及地震学、地热学) • 上一篇    下一篇

呼伦湖表层沉积物的磁性矿物组成特征

章敏1,2,3,潘永信1,2,3,*()   

  1. 1. 中国科学院地质与地球物理研究所地球与行星物理重点实验室,北京 100029
    2. 中国科学院地球科学研究院,北京 100029
    3. 中国科学院大学地球科学学院,北京 100049
  • 收稿日期:2018-05-22 修回日期:2018-10-24 出版日期:2019-02-20 发布日期:2019-04-15
  • 通讯作者: 潘永信 E-mail:yxpan@mail.iggcas.ac.cn
  • 作者简介:章敏,男,1993年生,中国科学院地质与地球物理研究所博士研究生,主要从事古生物地磁学研究.(E-mail: zhangmin173@mails.ucas.ac.cn)
  • 基金资助:
    国家自然科学基金项目(41621004);中国科学院前沿科学项目资助.(81612010)

Characterization of magnetic minerals in surface sediments of the Hulun Lake, Inner Mongolia

ZHANG Min1,2,3,PAN Yong-xin1,2,3,*()   

  1. 1. CAS Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
    2. Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China
    3. College of Earth Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-05-22 Revised:2018-10-24 Online:2019-02-20 Published:2019-04-15
  • Contact: Yong-xin PAN E-mail:yxpan@mail.iggcas.ac.cn

摘要:

本文选择内蒙古呼伦湖表层沉积物为研究对象,通过测量沉积物样品的室温下χ-T曲线、等温剩磁获得曲线和反向场退磁曲线、一阶反转曲线(FORC图)以及低温(20~300 K)下剩磁随温度变化曲线、Verwey转变温度,结合电子显微镜分析,获得了样品中磁性矿物组成信息.揭示出呼伦湖表层沉积物中磁性矿物含量较低,以假畴磁铁矿为主,含有部分单畴和多畴颗粒.这些结果对于理解呼伦湖沉积物的磁性信号、古环境和古气候重建等具有研究价值.

关键词: 呼伦湖, 岩石磁学, 表层沉积物, Verwey转换

Abstract:

Lacustrine-sediment is one of the best sources for environmental magnetic study. Identification of the magnetic minerals (both detrital and biogenic ones) in lake sediments is useful for understanding the magnetic signals and reconstructing paleo-environment and paleoclimate changes. The surface sediments of HuLun Lake in Inner Mongolia, which is the fifth largest freshwater lake of China, were studied using comprehensive rock magnetic measurements, including χ-T curve, magnetization/demagnetization curve of Isothermal Remanent Magnetization (IRM) and First-Order-Reversal Curve(FORC)diagram at room temperature, thermal demagnetization of Saturation Isothermal Remanent Magnetization (SIRM) at low temperature (20~300 K). Besides, transmission electron microscope was used to analyze the morphology of magnetic mineral extracted from the samples. Results indicate that magnetic mineral in recent sediments of HuLun Lake is mainly composed of single domain magnetite and a small amount of multi-domain magnetite. Magentite magnetofossils were found in the samples, showing by at lower temperature of Verwey transition (Tv) and central-ridge feature of the FORC diagrams.

Key words: HunLun Lake, Rock magnetism, Recent sediment, Verwey transition

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