Automated Image Analysis of Mud and Mudrock Microstructure and Characteristics of Hemipelagic Sediments: IODP Expedition 339
Automated Image Analysis of Mud and Mudrock Microstructure and Characteristics of Hemipelagic Sediments: IODP Expedition 339
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DOI：
10.1007/s12583-019-1210-4
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发表时间：
2019-04
影响因子：
3.3
通讯作者：
S. Bankole;J. Buckman;D. Stow;H. Lever
中科院分区：
文献类型：
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作者：
S. Bankole;J. Buckman;D. Stow;H. Lever
泥浆和泥岩的微观结构分析需要非常高分辨率的测量。电子显微镜技术的最新进展对改善泥岩微观结构及其岩石物理性质的表征做出了重大贡献。然而，通过电子显微镜成像仅限于小面积的覆盖范围，因此这些特性的升级是一个巨大的挑战。在本文中，我们开发了一种新的方法，多个大面积成像，使用扫描电子显微镜，通过自动采集和拼接抛光薄切片和离子研磨样品。该过程快速、高效，并最大限度地减少了用户输入和偏见。它可以提供关于沉积物颗粒大小、颗粒方向、孔隙大小和孔隙度的可靠、可量化的数据。局限性包括单个运行和手动分割所需的时间、所需的大量计算机内存以及纳米级的仪器分辨率。这种方法适用于选定的样品的第四纪泥质沉积物从伊比利亚边缘在IODP网站1385。该剖面由细粒（非常细的粘土质粉砂）、混合成分、生物-陆源半长岩组成，具有明显但不规则的颜色旋回性。深水Zoophycos遗迹相具有多层次、多样性的遗迹化石组合。沉积物的微观结构显示小规模的异质性，在所有的属性，和一个整体的随机织物与第二优先的颗粒排列。这些结果的织物不同，部分，从以前的研究半远洋泥。进一步的工作正在进行中，他们与其他深水沉积相的比较。
The microstructural analysis of muds and mudrocks requires very high-resolution measurement. Recent advances in electron microscopy have contributed significantly to the improved characterisation of mudrock microstructures and their consequent petrophysical properties. However, imaging through electron microscopy is limited to small areas of coverage such that upscaling of these properties is a great challenge. In this paper, we develop a new methodology for multiple large-area imaging using scanning electron microscopy through automated acquisition and stitching from polished thin-sections and ion-milled samples. The process is fast, efficient and minimises user-input and bias. It can provide reliable, quantifiable data on sediment grain size, grain orientation, pore size and porosity. Limitations include the time involved for individual runs and manual segmentation, the large amount of computer memory required, and instrument resolution at the nano-scale. This method is applied to selected samples of Quaternary muddy sediments from the Iberian margin at IODP Site 1385. The section comprises finegrained (very fine clayey silts), mixed-composition, biogenic-terrigenous hemipelagites, with a pronounced but non-regular colour cyclicity. There is a multi-tiered and diverse trace fossil assemblage of the deep-water Zoophycos ichnofacies. The sediment microstructures show small-scale heterogeneity in all properties, and an overall random fabric with secondary preferred grain-alignment. These results on the fabric differ, in part, from previous studies of hemipelagic muds. Further work is underway on their comparison with other deep-water sediment facies.