Three-dimensional imaging of ordinary chondrite microporosity at 2.6 μm resolution
Three-dimensional imaging of ordinary chondrite microporosity at 2.6 μm resolution
复制标题
DOI：
10.1016/j.gca.2011.08.045
复制
发表时间：
2013-09-01
影响因子：
5
通讯作者：
Rivers, Mark L.
中科院分区：
文献类型：
--
作者：
Friedrich, Jon M.;Rivers, Mark L.
我们发现，高分辨率（2.6 μ m/体素）同步辐射X射线显微断层扫描（μ CT）扫描能够观察到大多数的微孔在普通的alumentes。这种多孔性以矿物颗粒之间的微裂纹和空隙的形式存在。我们总共检查了7个小的（6-12 mm（3））芯片，分别是普通的Alpentes Baszkowka（L5，S1）、ALH A77258（H5，S2）、Moorleah（L 6，S3）和Kyushu（L 6，S5）。之所以选择这四个样本，是因为它们的撞击历史各不相同。使用mu CT和各种数字隔离和可视化技术，我们发现微孔结构随材料所经历的压实和冲击载荷的程度而变化。在压实和更强烈的冲击样品Moorleah和九州的微孔是可见的脆性硅酸盐内的片状断裂，以及在不连续的，分布的空隙，有时与球粒边缘和晶界。在经历了较少的冲击和只有温和的压实的样品中，我们发现很少，如果有的话，在材料的硅酸盐颗粒中的微裂纹。Baszkowka和ALH A77258样品中的微孔主要由晶间空隙表示，偶尔存在晶内空隙。无论冲击载荷的程度如何，韧性Fe-Ni或FeS颗粒没有证据表明与冲击相关的内部断裂有助于孔隙度。(C)2012爱思唯尔有限公司保留所有权利。
We show that high resolution (2.6 mu m/voxel) synchrotron X-ray microtomography (mu CT) scans are able to observe the majority of microporosity in ordinary chondrites. This porosity is present in the form of microcracks and voids among and between mineral grains. We examined, in total, seven small (6-12 mm(3)) chips of the ordinary chondrites Baszkowka (L5, S1), ALH A77258 (H5, S2), Moorleah (L6, S3), and Kyushu (L6, S5). These four samples were chosen because of their variable impact histories. Using mu CT and various digital isolation and visualization techniques, we found that the structure of microporosity varies with the degree of compaction and shock loading experienced by the materials. The microporosity in the compacted and more strongly shock samples Moorleah and Kyushu is visible as sheet-like fractures within brittle silicates as well as in discontinuous, distributed voids sometimes associated with chondrule rims and grain boundaries. In samples that have experienced less shock and only mild compaction, we found few, if any, microcracks in the silicate grains of the materials. Microporosity in the Baszkowka and ALH A77258 samples is largely represented by intergranular voids, with occasional intragranular voids being present. Regardless of degree of shock loading, ductile Fe-Ni or FeS grains give no evidence of shock-related internal fractures contributing to porosity. (C) 2012 Elsevier Ltd. All rights reserved.