| 亚热带地区发育于不同母岩风化壳上的红壤磁学特征对比及其环境意义 |
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| 引用本文： | 郑兴芬,吕镔,陈梓炫,马兴悦,赵国永.亚热带地区发育于不同母岩风化壳上的红壤磁学特征对比及其环境意义[J].地球物理学报,2019,62(9):3509-3523. |
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| 作者姓名： | 郑兴芬 吕镔 陈梓炫 马兴悦 赵国永 |
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| 作者单位： | 1. 福建师范大学湿润亚热带山地生态国家重点实验室培育基地, 福州 350007;2. 福建师范大学地理科学学院, 福州 350007;3. 福建师范大学地理研究所, 福州 350007;4. 信阳师范学院地理科学学院, 河南信阳 464000 |
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| 基金项目： | 国家自然科学基金项目（41877435和41602187）和福建师范大学创新团队项目（IRTL1705）资助. |
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| 摘 要： | 本研究对发育于亚热带地区花岗岩和变质岩风化壳之上的两个红壤剖面进行了系统的环境磁学测量及色度分析，探讨在同一地区不同母质上发育的红壤磁性差异的原因及其环境意义.研究区的两个剖面分别位于福建省南平市高铁北站和纺织厂附近，相距约15 km，气候条件基本相同.研究结果表明：（1）较强磁性的花岗岩母质层上发育的南平北站红壤（NPN），在发育过程因母质层中多畴（MD）颗粒磁赤铁矿化的磁铁矿溶解，剖面上部的淋溶层和淀积层虽以较细的稳定单畴（SSD）颗粒和少量的假单畴（PSD）颗粒磁铁矿为主，但剖面磁性自下而上减弱.相较而言，南纺红壤（NF）剖面发育在磁性较弱的变质砂岩上，其过渡层和母质层以赤铁矿为主，因成壤过程中生成较细的超顺磁（SP）磁铁矿使得土壤淋溶层和淀积层磁性增强；说明母质不同是亚热带地区红壤磁性差异的主要原因.（2） NPN和NF两个剖面的气候条件基本相同，磁性差异比色度指标差异更为显著.亚热带地区因剖面受母质影响显著，整体磁性特征不能反映气候；黄度和红度的比值（b*/a*）远小于磁性的差异，说明针铁矿和赤铁矿的比值更能反映研究区的平均气候状况，即反映次生磁性矿物含量的参数为更适合的气候指标.
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| 关 键 词： | 亚热带地区 红壤 环境磁学 磁性矿物 |
| 收稿时间： | 2018-04-13 |
A comparative analysis of magnetic properties of subtropical red soil derived from different weathering crusts |
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| ZHENG XingFen,Lü Bin,CHEN ZiXuan,MA XingYue,ZHAO GuoYong.A comparative analysis of magnetic properties of subtropical red soil derived from different weathering crusts[J].Chinese Journal of Geophysics,2019,62(9):3509-3523. |
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| Authors: | ZHENG XingFen Lü Bin CHEN ZiXuan MA XingYue ZHAO GuoYong |
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| Institution: | 1. State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, Fujian Normal University, Fuzhou 350007, China;2. School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China;3. Institute of Geography, Fujian Normal University, Fuzhou 350007, China;4. School of Geographical Sciences, Xinyang Normal University, Xinyang Henan 464000, China |
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| Abstract: | Environmental magnetism has been successfully used in the study of paleoenvironment and paleoclimate change. The red soil is widely distributing in Southern China. In this study, we conducted a systematic analysis by environmental magnetism and the color to study magnetic differences and possible causes of subtropical red soil derived from different parent rock weathering crust. Two red soil sections which respectively derived from granite and metamorphic weathering crust locate in Nanping City, Fujian Province. Two sections are about 15 kilometers far away from each other, and have the similar climatic conditions. The results show that:(1) The parent material of the Nanping North Station red soil (NPN) section is a relatively strongly magnetic granite. Due to dissolution of more coarse multi-domain (MD) magnetite to stable single domain (SSD) particles and a small amount of Pseudo-single domain (PSD) magnetite particles during pedogenesis, there is a decrease trend of magnetic susceptibility from bottom to top of the section. In contrast, the Nanfang red soil (NF) section is derived from weakly magnetic metasandstone, with the base of hematite at the transition layer and parent material layer, the magnetic enhancement in the upper part of the section is due to the formation of finer superparamagnetic (SP) magnetic particles during pedogenesis. It indicates that the different parent material is the main reason for the difference in magnetic properties of red soils in subtropical regions. (2) The climatic conditions of the two sections of NPN and NF are basically the same, and the magnetic parameters differences are more obvious than the color indexes. Because of the different parent material of profiles, the relationship between magnetic properties and climate is ambiguous. The ratio of yellowness to redness (b*/a*) is far less than the magnetic differences, suggesting that the ratio of goethite to hematite can more accurately reflect the average climatic conditions in the study area, that is, the secondary magnetic minerals are more suitable climatic indicators of red soil in the subtropical zone. |
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| Keywords: | Subtropical region Red soil Environmental magnetism Magnetic minerals |
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