Quantitative textural analysis of Vulcanian pyroclasts (Montserrat) using multi-scale X-ray computed microtomography: comparison with results from 2D image analysis
Quantitative textural analysis of Vulcanian pyroclasts (Montserrat) using multi-scale X-ray computed microtomography: comparison with results from 2D image analysis
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使用多尺度 X 射线计算机显微断层扫描对伏尔甘火山碎屑（蒙特塞拉特）进行定量结构分析：与 2D 图像分析结果的比较
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发表时间：
2011
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通讯作者：
Karim Kelfoun
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作者：
T. Giachetti;A. Burgisser;L. Arbaret;T. Druitt;T. Druitt;Karim Kelfoun;Karim Kelfoun
对1997年蒙特塞拉特苏弗里耶尔山火山火山爆发的四个火山碎屑进行了X射线计算机微断层扫描。将来自不同空间分辨率（0.37、4-8和17.4 μm px−1）的多个图像堆栈的三维数据进行组合，以生成3.4-860 μm尺寸范围内的囊泡、囊泡间喉道、晶体和Fe-Ti氧化物的尺寸分布，并将结果与通过相同样品的二维图像分析获得的结果进行比较。定性纹理观察结果与2D观察结果一致，但μCT提供了更好的纹理特征和空间关系分辨率。尺寸分布的计算需要连接的囊泡网络的自动退吸热。与此过程有关的问题，部分是由于浮石的高孔隙度，导致在计算的粒度分布，这是详细讨论的潜在文物。与2D分布相比，3D囊泡体积分布的主要模式被系统地转移到更大的尺寸。在3D中获得的样品总囊泡率在13体积%以内在2D中发现的那些，并且在10体积%内用He测比重法测得的。两种方法得到的囊泡和Fe-Ti氧化物的总数密度仅在一级一致，3D值为2D值的37%~ 309%。囊泡聚结，研究囊泡间喉的大小分布，发生在许多大小的相邻囊泡之间的所有火山碎屑。囊泡越大，连接越紧密。
X-ray computed microtomography (μCT) was carried out on four pyroclasts from the 1997 Vulcanian explosions of Soufrière Hills Volcano, Montserrat. Three-dimensional data from multiple image stacks with different spatial resolutions (0.37, 4–8, and 17.4 μm px−1) were combined to generate size distributions of vesicles, inter-vesicle throats, crystals, and Fe–Ti oxides over a 3.4–860-μm size range, and to compare the results with those obtained by 2D image analysis on the same samples. Qualitative textural observations are in good agreement with those made in 2D, but μCT provides better resolution of textural features and spatial relationships. Calculation of size distributions requires automated decoalescence of the connected vesicle network. Problems related to this process, in part due to the high porosity of pumice, result in potential artefacts in the calculated size distributions, which are discussed in detail. The main modes of the 3D vesicle volume distributions are systematically shifted to larger sizes compared with those of the 2D distributions. Sample total vesicularities obtained in 3D are within 13 vol.% of those found in 2D, and within 10 vol.% of those measured by He-pycnometry. Total number densities of vesicles and Fe–Ti oxides from the two methods are consistent only to the first order, 3D values ranging from 37% to 309% of those in 2D. Vesicle coalescence, investigated by examining inter-vesicle throat size distributions, occurred in all pyroclasts between neighbouring vesicles of many sizes. The larger the vesicle, the more connected it is.