气候变化领域集成服务门户(CCPortal): Two geomagnetic excursions during the Brunhes chron recorded in Chinese loess-palaeosol sediments

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DOI	10.1111/j.1365-246X.2007.03522.x
	Two geomagnetic excursions during the Brunhes chron recorded in Chinese loess-palaeosol sediments
	Yang, Tianshui; Hyodo, Masayuki; Yang, Zhenyu; Fu, Jianli
发表日期	2007
ISSN	0956-540X
起始页码	104
结束页码	114
卷号	171 期号:1
英文摘要	Detailed palaeomagnetic integrated with rock magnetic studies have been carried out on a loess-palaeosol sequence in Baoji, Shaanxi province, southern Chinese Loess Plateau. For most samples stepwise thermal demagnetization revealed two well-defined magnetization components. A low-temperature component (LTC), which was isolated between 100 and 200 degrees C, is consistent with the present geomagnetic field direction. A high-temperature component (HTC), which was isolated between 250 and 620-680 degrees C, shows normal, reversed or transitional polarities. Our new magnetostatigraphy revealed two distinct geomagnetic excursions recorded in loess unit of L5 and palaeosol unit of S7, respectively, and the Matuyama-Brunhes (M-B) polarity boundary in loess unit of L8. Rock magnetic experiments demonstrated that the specimens from the excursion zones have the same magnetic properties as those from the Brunhes normal or Matuyama reversed polarity zones. Measurements of anisotropy of magnetic susceptibility (AMS) showed that the sediments have primary sedimentary fabrics. Based on the palaeoclimatological and magnetostratigraphic age models, the middle Brunhes excursion in loess L5 is dated at 413-433 ka, and the early Brunhes excursion is estimated to occur 23-33 ka after the M-B reversal. Comparing with previously reported geomagnetic excursions in the Brunhes chron, the middle Brunhes excursion (L5) is likely global. For the early Brunhes excursion (S7), we need further studies to examine its global occurrence.
关键词	NORTH-CENTRAL CHINA LAST 1.2 MYR LOESS/PALAEOSOL SEQUENCE LOESS/PALEOSOL SEQUENCES ASTRONOMICAL CALIBRATION ICELAND BASIN PLATEAU DEPOSITS MAGNETOSTRATIGRAPHY TIMESCALE
英文关键词	Brunhes chron; Chinese loess; geomagnetic excursion; Matuyama-Brunhes reversal; palaeomagnetism
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000250079100007
来源期刊	GEOPHYSICAL JOURNAL INTERNATIONAL
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/257510
推荐引用方式 GB/T 7714	Yang, Tianshui,Hyodo, Masayuki,Yang, Zhenyu,et al. Two geomagnetic excursions during the Brunhes chron recorded in Chinese loess-palaeosol sediments[J]. 中国科学院青藏高原研究所,2007,171(1).
APA	Yang, Tianshui,Hyodo, Masayuki,Yang, Zhenyu,&Fu, Jianli.(2007).Two geomagnetic excursions during the Brunhes chron recorded in Chinese loess-palaeosol sediments.GEOPHYSICAL JOURNAL INTERNATIONAL,171(1).
MLA	Yang, Tianshui,et al."Two geomagnetic excursions during the Brunhes chron recorded in Chinese loess-palaeosol sediments".GEOPHYSICAL JOURNAL INTERNATIONAL 171.1(2007).