Pore morphology and distribution in the Shaly facies of Opalinus Clay (Mont Terri, Switzerland): Insights from representative 2D BIB-SEM investigations on mm to nm scale
Pore morphology and distribution in the Shaly facies of Opalinus Clay (Mont Terri, Switzerland): Insights from representative 2D BIB-SEM investigations on mm to nm scale
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DOI：
10.1016/j.clay.2012.11.006
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发表时间：
2013-01-01
影响因子：
5.6
通讯作者：
Urai, J. L.
中科院分区：
文献类型：
--
作者：
Houben, M. E.;Desbois, G.;Urai, J. L.
我们使用宽离子束抛光结合扫描电子显微镜研究的显微结构和孔隙度的Opalinus粘土（北方瑞士）的泥质相。在几纳米的分辨率下，我们研究了大约1 mm（2）的区域，该区域足够大，可以在统计上代表微观结构。在三个样本从1米长的钻孔岩芯从山特里实验室，定性描述的微观结构结合定量描述的孔隙度。在粘土基质、菱铁矿、黄铁矿类和贝壳化石中分别识别出8种不同的矿物相和6种不同的孔隙类型。粘土基质中的孔径具有指数为2.4的幂律分布。从BIB-SEM方法推断的孔隙率与使用压汞法测量的孔隙率相当。根据垂直和平行于层理拍摄的显微照片，我们表明孔隙和矿物在3D中均匀分布，并提出了Opalinus粘土泥质相的显微结构模型。该模型定义了具有相似孔隙特征的可预测均质多孔和无孔区域。结合起来，这些形成了Opalinus粘土（页岩相）的异质结构。(C)2012爱思唯尔有限公司版权所有。
We used Broad-Ion-Beam polishing in combination with Scanning Electron Microscopy to study the microstructure and porosity in the Shaly fades of Opalinus Clay (northern Switzerland). With resolutions of a few nm, we studied areas of around 1 mm(2), sufficiently large to be statistically representative for the microstructure. In three samples from a 1 m long drill core from the Mt Terri laboratory, a qualitative description of the microstructure was combined with quantitative description of porosity. Eight different mineral phases and six different pore types are identified, in the clay matrix, siderite, pyrite framboids and fossil shells respectively. Pore sizes in the clay matrix have a power law distribution with an exponent of 2.4. Porosity inferred from the BIB-SEM method is comparable to that measured using mercury porosimetry. Based on micrographs made perpendicular and parallel to the bedding we show that pores and minerals are homogeneously distributed in 3D, and present a microstructural model for the Shaly facies of Opalinus Clay. This model defines predictable homogeneous porous and non-porous regions with similar pore characteristics. Combined, these form the heterogeneous fabric of Opalinus Clay (Shaly facies). (C) 2012 Elsevier B.V. All rights reserved.