Mineral magnetic properties of a weathering sequence of soils derived from basalt in Eastern China
Mineral magnetic properties of a weathering sequence of soils derived from basalt in Eastern China
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DOI：
10.1016/j.catena.2007.08.004
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发表时间：
2008-03
期刊：
影响因子：
6.2
通讯作者：
Shenggao Lu;Q. Xue;Lei Zhu;Jin-Yan Yu
中科院分区：
文献类型：
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作者：
Shenggao Lu;Q. Xue;Lei Zhu;Jin-Yan Yu
通过岩石磁学、X射线衍射和土壤化学分析，研究了中国东部玄武岩母质上发育的风化土壤的磁性和磁性矿物学特征，探讨了亚热带地区矿物磁性与成壤作用的关系。玄武岩上形成的土壤的磁化率变化很大，并不随着成土发育程度的增加而增加。土壤磁化率的频率依赖系数（χ fd）变化范围为1.0~11.1%，随成土作用的发展而增大。频率磁化率与土壤中Fe含量（R2 = 0.683）和Fe/Fe比值（R2 = 0.780）呈极显著线性关系，说明土壤次生氧化铁矿物的富集与土壤次生铁磁性颗粒的形成有关。岩石磁学分析表明，弱风化土壤剖面中的主要磁性载体为磁铁矿和/或磁赤铁矿，发育程度较高的土壤剖面一般富集成壤成因的磁铁矿/磁赤铁矿颗粒和硬磁性赤铁矿，表明成壤发育过程中磁性组分由亚铁磁相（磁铁矿）向反铁磁相（赤铁矿）转化。结果表明，土壤的某些磁性参数（χ fd）可用于土壤风化序列的成土对比和年代关联。因此，多参数岩石磁学调查是一个更强大的方法成壤。
The magnetic properties and magnetic mineralogy of a weathering sequence of soils developed on basalt parent material from eastern China, were studied by rock magnetism, X-ray diffraction and soil chemical analyses to establish the connection between mineral magnetic properties and pedogenic development in a subtropical region. The magnetic susceptibility of soils formed on basalt varied greatly and did not increase with the degree of pedogenic development. The frequency-dependent susceptibility (χfd) values of soils ranged from 1.0 to 11.1% and increased with the pedogenic development. Highly significant linear relationship was found between the frequency-dependent susceptibility and the Fedcontent (R2=0.683) and Fed/Fetratio (R2=0.780) in soils, indicating that pedogenic SP ferrimagnetic grains were associated with enrichment of the secondary iron oxide minerals in the weathering process of soil. Rock magnetism analysis showed that the major magnetic carriers in the weakly weathered soil profiles are magnetite and/or maghemite, and the highly developed soil profiles are generally enriched in magnetite/maghemite grains of pedogenic origin and the magnetically hard haematite, indicating that the magnetic component was transformed from a ferrimagnetic phase (magnetite) to antiferromagnetic phase (hematite) during pedogenic development. Results indicated that some of the magnetic parameters of soils, in this case χfd, can be useful for pedogenic comparisons and age correlations in the weathering sequence of soil. It is thus suggested that multiparameter rock magnetic investigations represent a more powerful approach for pedogenesis.