DOI: 10.1016/j.palaeo.2013.04.010
论文题名: Rock magnetism, iron oxide mineralogy and geochemistry of Quaternary red earth in central China and their paleopedogenic implication
作者: Wang S. ; Lin S. ; Lu S.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 379-380 起始页码: 95
结束页码: 103
语种: 英语
英文关键词: Iron oxide
; Paleopedogenesis
; Quaternary red earth (QRE)
; Rock magnetism
; Weathering index
英文摘要: This paper presents a detailed investigation on the rock magnetism, iron oxidemineralogy and geochemistry of a Quaternary red earth (QRE) in central China. The magnetic profile of QRE showed a characteristic vertical variation pattern: the uniformred clay (URC) section (0.2-2 m) of the profile had a higher magnetic susceptibility (χ) while vermiculated red clay (VRC) section (2-6 m) had a very lowχ (<30 × 10-8 m3 kg-1). Rock magnetism and differential XRD analysis revealed that magnetite/maghemite and hematite were themainmagnetic carriers in the URC section. Themajor elements Fe2O3 and Al2O3 of QRE increased with depth while the SiO2 content decreasedwith depth, indicating a leaching of themobile elements and an enrichment of the immobile elements. In comparisonwith the URC, the VRC has a greater depletion in the content of Na, Mg, K andMg, indicating a stronger weathering intensity. The dithionite-citrate-bicarbonate (DCB) extracted iron (Fed), the ratio of Fed to total iron oxide (Fe/Fet), and theweathering indices of QRE confirmed that the VRC had experienced a stronger pedogenesis than the URC. Strong pedogenesis in the VRC resulted in a transformation of the highly magnetic maghemite to the weaklymagnetic hematite,which was responsible for the weakmagnetismand hardmagnetic behavior of the VRC. Our studies suggest that the VRC had experienced a hot climate with a dry season following one that was warm and moister. Magnetic reduction of the VRC section resulting from the transformation of highly magnetic maghemite to weaklymagnetic hematite appeared to be an important paleopedogenic process in the QRE.We concluded that the magnetic parameters, hard isothermal remanent magnetization (HIRM) and SIRM/χ of QRE, can be used for the analysis of paleopedogenic processes. © 2013 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69737
Appears in Collections: 过去全球变化的重建
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作者单位: College of Environmental and Resource Sciences, Zhejiang University, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrient, Hangzhou 310058, China
Recommended Citation:
Wang S.,Lin S.,Lu S.. Rock magnetism, iron oxide mineralogy and geochemistry of Quaternary red earth in central China and their paleopedogenic implication[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,379-380