Iron and Manganese Distribution in Nodules from a Young Texas Vertisol
Iron and Manganese Distribution in Nodules from a Young Texas Vertisol
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DOI：
10.2136/sssaj1996.03615995006000040042x
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发表时间：
1996-07
影响因子：
2.9
通讯作者：
G. White;J. Dixon
中科院分区：
文献类型：
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作者：
G. White;J. Dixon
铁和锰分布在黑色结核从BCK3地平线的微低位置的伯莱森土壤，细，蒙脱石，热，Udic Haplustert，从一个平台的Brazos河绘制了扫描电子显微镜/能谱（SEM/EDS）的X射线分析。球形结核呈同心带状，不规则形结核缺乏Fe、Mn的显带。通过减少用于映射的像素大小和增加带状结节的每个像素的计数时间，发现更多和更好地表达带状。Fe和Mn的高、低浓度谱带并不重合。通过EDS分析的单个结核的Mn/Fe重量比在0.71至2.85之间。带状结核与无带状结核相比，锰和铁的浓度范围较窄，锰与铁的比率范围也较窄。结核中钡的含量异常高，平均为30 g kg-1，并与锰的含量密切相关。一些元素间的相关性（例如，Fe对Mn，r =-0.56; Fe对Al，r =-0.58）反映了土壤中氧化物或硅酸盐矿物的分配。破碎的结节显示内部只有几个非常小的孔隙。检查的30个结核是发育良好的固体，预计将在土壤环境中持续存在。它们似乎包含了关于伯莱森土壤风化历史及其所在景观的独特而重要的信息。这些条带的排列顺序和表现形式是结核氧化还原历史的遗迹，可以用来推断土壤的氧化还原历史。
Iron and Mn distributions in the black nodules from the BCk3 horizon of the microlow position of a Burleson soil, a fine, montmorillonitic, thermic, Udic Haplustert, from a terrace of the Brazos River were mapped with scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) x-ray analysis. Spherical nodules were concentrically banded, and the irregularly shaped nodules lacked welldeveloped banding of Fe and Mn. More and better expressed banding was found by decreasing pixel size used for mapping and by increasing the count time per pixel for banded nodules. Bands of higher or lower Fe and Mn concentration were not coincident. The Mn/Fe weight ratios of individual nodules analyzed by EDS were between 0.71 to 2.85. Banded nodules had a narrower range of Mn and Fe concentrations and a narrower range in Mn to Fe ratios than unbanded nodules. Barium concentration in the nodules was unusually high, averaging 30 g kg -1 , and correlated strongly with Mn concentration. Some interelement correlations (e.g., Fe vs. Mn, r = - 0.56; Fe vs. Al, r = - 0.58) reflected partitioning into the oxide or silicate minerals of the soil. Fractured nodules revealed the interior to have only a few very small pores. The 30 nodules examined are well developed solid bodies that are expected to persist in the soil environment. They appear to contain unique and important information about the weathering history of the Burleson soil and the landscape in which it occurs. The order and expression of the banding is a relict of the redox history of the nodules, which can be used to induce the redox history of the soil.