The magnetic properties of loess and paleosol samples from the Chinese Loess Plateau spanning the last 22 million years

doi:10.1016/j.palaeo.2007.11.010

IGGCAS OpenIR

	The magnetic properties of loess and paleosol samples from the Chinese Loess Plateau spanning the last 22 million years
	Hao, Qingzhen 1,2; Oldfield, Frank 1; Bloemendal, Jan 1; Guo, Zhengtang 2
	2008-04-14
发表期刊	PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
ISSN	0031-0182
卷号	260 期号:3-4 页码:389-404
文章类型	Article
摘要	Magnetic measurements (susceptibility, isothermal and anhysteretic remanence, and quotients derived from these) are presented for a suite of loess and paleosol samples from sites on the Chinese Loess Plateau. The three sites, Xifeng, Dongwan and Qinan (QA-I), together span most of the last 22 million years. The results provide the first multi-parameter magnetic measurements from pre-Pleistocene loess/paleosol sequences that began accumulation in the early Miocene. Mass specific measurements have been corrected for carbonate concentrations which peak in the loess layers and range up to 57%. All the magnetic properties recorded indicate variability on both orbital and supra-orbital timescales. The changing magnetic properties allow the record to be divided into a sequence of eight sample groups that broadly parallel the main supra-orbital changes in magnetic susceptibility. The pre-Pleistocene parts of the record include intervals (mainly late Miocene and Pliocene) during which loess as well as paleosol layers are characterized by high values for properties such as frequency dependent susceptibility (chi(fd)), usually associated with strong weathering. Most of the Miocene record prior to 8.5 Ma, with the exception of a brief interval from ca. 14.4 to 15.9 Ma, shows reduced values for indicators of pedogenic ferrimagnetic concentrations in both the loess and paleosol layers, as well as a low amplitude of variability between loess and paleosol values. The palaeoenvironmental implications of this part of the sequence are unclear since they hinge on the type of model of pedogenic magnetic mineral formation adopted. High-field remanence measurements indicate that the coercivity of the antiferromagnetic minerals represented declined progressively throughout the whole period in both the loess and the paleosol samples, though there is no unambiguous evidence for long-term diagenetic alteration of the magnetic properties on timescales beyond the orbital ones that drive the loess/palcosol alternations. The present results suggest caution in applying existing climofunctions based on magnetic susceptibility to deposits spanning the whole of the last 22 Ma. (C) 2008 Elsevier B.V. All rights reserved.
关键词	loess environmental magnetism neogene palaeoenvironment China
WOS标题词	Science & Technology ; Physical Sciences ; Life Sciences & Biomedicine
DOI	10.1016/j.palaeo.2007.11.010
关键词[WOS]	RED-EARTH FORMATION ; SOIL SEQUENCE ; GRAIN-SIZE ; PALEOCLIMATIC SIGNIFICANCE ; NATURAL GOETHITE ; NORTHERN CHINA ; ORIGIN ; SUSCEPTIBILITY ; QINAN ; PALAEOPRECIPITATION
收录类别	SCI
语种	英语
WOS研究方向	Physical Geography ; Geology ; Paleontology
WOS类目	Geography, Physical ; Geosciences, Multidisciplinary ; Paleontology
WOS记录号	WOS:000255474200007
出版者	ELSEVIER SCIENCE BV
引用统计
文献类型	期刊论文
条目标识符	http://ir.iggcas.ac.cn/handle/132A11/69569
专题	中国科学院地质与地球物理研究所
通讯作者	Oldfield, Frank
作者单位	1.Univ Liverpool, Dept Geog, Liverpool L69 7ZT, Merseyside, England 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
第一作者单位	中国科学院地质与地球物理研究所
推荐引用方式 GB/T 7714	Hao, Qingzhen,Oldfield, Frank,Bloemendal, Jan,et al. The magnetic properties of loess and paleosol samples from the Chinese Loess Plateau spanning the last 22 million years[J]. PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,2008,260(3-4):389-404.
APA	Hao, Qingzhen,Oldfield, Frank,Bloemendal, Jan,&Guo, Zhengtang.(2008).The magnetic properties of loess and paleosol samples from the Chinese Loess Plateau spanning the last 22 million years.PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,260(3-4),389-404.
MLA	Hao, Qingzhen,et al."The magnetic properties of loess and paleosol samples from the Chinese Loess Plateau spanning the last 22 million years".PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY 260.3-4(2008):389-404.