The magnetic properties of loess and paleosol samples from the Chinese Loess Plateau spanning the last 22 million years | |
Hao, Qingzhen1,2; Oldfield, Frank1; Bloemendal, Jan1; Guo, Zhengtang2 | |
刊名 | PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY |
2008-04-14 | |
卷号 | 260期号:3-4页码:389-404 |
关键词 | loess environmental magnetism neogene palaeoenvironment China |
ISSN号 | 0031-0182 |
DOI | 10.1016/j.palaeo.2007.11.010 |
文献子类 | Article |
英文摘要 | 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. |
WOS关键词 | RED-EARTH FORMATION ; SOIL SEQUENCE ; GRAIN-SIZE ; PALEOCLIMATIC SIGNIFICANCE ; NATURAL GOETHITE ; NORTHERN CHINA ; ORIGIN ; SUSCEPTIBILITY ; QINAN ; PALAEOPRECIPITATION |
WOS研究方向 | Physical Geography ; Geology ; Paleontology |
语种 | 英语 |
出版者 | ELSEVIER SCIENCE BV |
WOS记录号 | WOS:000255474200007 |
内容类型 | 期刊论文 |
源URL | [http://ir.iggcas.ac.cn/handle/132A11/69568] |
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 |
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. |
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