王浩森^1,,
徐行²,
刘青松^1,,,
仲义^1,5,
陈艇¹,
强小科³,
周祐民¹,
杨小强⁴
1. 南方科技大学海洋科学与工程系, 海洋磁学中心 (CM²), 深圳 518055
2. 广州海洋地质调查局, 广州 510760
3. 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, 西安 710061
4. 中山大学地球科学与地质工程学院, 广州 510275
5. 中国科学院大学, 北京 100049

基金项目: 国家基金委—山东省联合基金项目—海洋地质过程与环境项目（U1606401），"全球变化与海气相互作用"专项（GASI-GEOGE-03），以及NSFC（41874078，41806063和91428205）资助


详细信息

作者简介: 王浩森, 男, 1994年出生, 博士生, 海洋地质专业, 主要从事海洋沉积物的古地磁学的研究.E-mail:11749140@mail.sustech.edu.cn

通讯作者: 刘青松, 男, 1972年生, 博士, 教授, 主要从事岩石磁学与环境磁学的研究.E-mail:qsliu@sustech.edu.cn

中图分类号: P318

收稿日期:2019-09-20
修回日期:2020-01-03
上线日期:2020-07-05

Geomagnetic paleointensity and its geodynamic significance for the last 40 ka recorded in the northwestern sub-sea basin of the South China Sea

WANG HaoSen^1,,
XU Xing²,
LIU QingSong^1,,,
ZHONG Yi^1,5,
CHEN Ting¹,
QIANG XiaoKe³,
CHOU YuMin¹,
YANG XiaoQiang⁴
1. Centre of Marine Magnetism(CM²), Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
2. Guangzhou Marine Geological Survey, Guangzhou 510760, China
3. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
4. Department of Earth Sciences, Sun Yat-Sen University, Guangzhou 510275, China
5. University of Chinese Academy of Sciences, Beijing 100049, China


More Information

Corresponding author: LIU QingSong,E-mail:qsliu@sustech.edu.cn

MSC: P318

--> Received Date: 20 September 2019
Revised Date: 03 January 2020
Available Online: 05 July 2020


摘要
摘要:海洋沉积物能够记录较为连续的古地磁信息.对沉积物记录的天然剩磁（NRM）进行归一化处理，可以构建过去较为连续的地磁场相对古强度（RPI）信息，这对于研究地磁场演变与全球记录对比具有重要的科学意义.本文以南海西北次海盆地区L07岩芯作为研究对象，利用等温剩磁（IRM）作为NRM的归一化参数，构建了南海西北次海盆地区37 ka以来的RPI曲线.实验结果显示，L07岩芯中载磁矿物的成分较为单一，以单畴（SD）-细粒准单畴（PSD）低矫顽力磁铁矿为主，能够作为古强度记录的载体.此外，在11.5 ka处RPI出现峰值.进一步结合东亚地区鄂霍茨克海岩芯的RPI记录以及中国黄土¹⁰Be的丰度变化，我们认为该RPI峰值是由于地球非偶极子场影响所致.这说明东亚正磁异常的影响范围可以达到中国南海等中低纬度地区，这为理解东亚地区磁场演化提供了新证据，同时也为该区千年尺度RPI记录变化特征提供了新机制.
关键词: 南海西北次海盆/
地磁场相对古强度/
非偶极子场/
地球动力学/
东亚磁异常

Abstract:Marine sediments can record relatively continuous paleomagnetic information. Normalized natural remanent magnetization (NRM) records of sediments can be used to construct continuous relative paleointensity (RPI) information of the paleomagnetic field,which facilitates studying evolution of the geomagnetic field and global record correlations. This paper investigated the gravity core L07 drilled from the northwestern sub-sea basin of the South China Sea. By using isothermal remanent magnetization (IRM) as the normalization parameter,RPI curve was constructed for the past 37 ka. Results show that the dominant magnetic minerals in the L07 are mainly (pseudo) single domain (PSD/SD) magnetite particles. In addition,RPI value maximized at 11.5 ka. By further combining the RPI records of the Okhotsk sea core in East Asia and the abundance changes of ¹⁰Be in China Loess,we attribute the RPI peak to the Earth's non-dipole field. Our results indicate that the influence of positive magnetic anomalies in East Asia can reach to low latitude area such as the South China Sea. This greatly improves our understanding the evolution of magnetic fields in East Asia and provides a possible mechanism for change in the millennium scale's RPI characteristics in this region.
Key words:Northwestern sub-sea basin of the South China Sea/
Relative paleointensity/
Non-dipole field/
Geodynamics/
East Asian positive magnetic anomaly



PDF全文下载地址:

http://www.geophy.cn/data/article/export-pdf?id=dqwlxb_15516