Direct identification of biotite/vermiculite layers in hydrobiotite using high-resolution TEM
Direct identification of biotite/vermiculite layers in hydrobiotite using high-resolution TEM
复制标题
使用高分辨率 TEM 直接识别水黑云母中的黑云母/蛭石层
DOI：
10.2465/minerj.18.131
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
T. Murakami
中科院分区：
文献类型：
--
作者：
T. Kogure;T. Murakami
通过高分辨率透射电子显微镜（HRTEM）检查了水黑云母（间层黑云母/蛭石）的微观结构，以证明对矿物风化的原子尺度研究。蛭石基底间距塌陷到约0.95 nm，相比不变的黑云母1.0 nm的间距，通过脱水可能在离子研磨样品制备。0.2 nm点分辨率的原子分辨结构图像显示含钾和贫钾夹层之间的明显差异，分别对应于黑云母和蛭石。因此，图像中的差异使我们能够明确地识别水黑云母中的蛭石层位置。虽然蛭石层是随机形成在原始黑云母，有一个趋势，形成1：1规则的黑云母/蛭石间层局部。在某些夹层中，钾柱的对比度逐渐变化，表明黑云母在风化过程中直接转化为蛭石。这些观察结果表明，原子分辨高分辨透射电镜是一个有用的方法，结构分析等含水的次生矿物蛭石，尽管间距的变化引起的样品制备或观察过程中的TEM。
The microstructure of hydrobiotite, interstratified biotite/vermiculite, was examined to demonstrate an atomic scale investigation of weathering of minerals by high-resolution transmission electron microscopy (HRTEM). Vermiculite basal spacing was collapsed to about 0.95 nm, compared to the unchanged biotite 1.0 nm spacing, by dehydration probably during the ion-milling sample preparation. Atom-resolving structure images with 0.2 nm point resolution show a distinct difference between K-containing and K-depleted interlayers, corresponding to biotite and vermiculite respectively. Thus, the difference in image enables us to identify vermiculite layer positions in hydrobiotite unambiguously. Although the vermiculite layers are randomly formed in the original biotite, there is a tendency to form 1:1 regular biotite/vermiculite interstratification locally. In some interlayers the contrast of potassium columns changed gradually, which suggests that biotite is directly transformed to vermiculite in the weathering process. These observations demonstrate atom-resolving HRTEM is a useful method for structure analyses of such water containing secondary minerals as vermiculite in spite of spacing changes caused during sample preparation or observation in TEM.