Tomography: A window on the role of sulfur in the structure of micrometeorites
Tomography: A window on the role of sulfur in the structure of micrometeorites
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DOI：
10.1111/j.1945-5100.2011.01245.x
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发表时间：
2011-10
影响因子：
2.2
通讯作者：
S. Taylor;K. Jones;G. Herzog;C. E. Hornig
中科院分区：
文献类型：
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作者：
S. Taylor;K. Jones;G. Herzog;C. E. Hornig
翻译后摘要-要确定硫化物在形成的囊泡和FeNi金属珠所发挥的作用，我们映射的位置和制表的硫化物，金属珠，和囊泡的数量在1583切片微陨石（微陨石）使用传统的显微镜和190整个微陨石使用同步辐射计算机显微断层扫描（SCMT）。剖面和SCMT图像均显示硫化物熔融、聚结并迁移至地幔表面。硫化物的分解可能发生在所有这些阶段。鉴于硫化物的形态和成分，我们看到的部分，我们认为镍硫化物的分解产生FeNi珠。SCMT图像显示，金属珠是常见的熔融铝合金，>50%有他们。随着硫化物分解，斑状和火山渣状MM中的囊泡也可能形成。不仅硫化物邻接的囊泡，而且硫化物分解的温度重叠的MM表面第一次熔化和暂时密封，这表明S气体可以产生这些囊泡的大部分。由于囊泡的形状和分布模式在MM类别中不同，因此可以使用断层扫描来非破坏性地筛选特定类型的囊泡。断层扫描是一种强大的工具，用于可视化金属珠，硫化物，平均密度和囊泡在血管中的三维分布。
Abstract– To determine the role played by sulfides in the formation of vesicles and FeNi metal beads, we mapped the locations and tabulated the numbers of sulfides, metal beads, and vesicles in 1583 sectioned micrometeorites (MMs) using conventional microscopy and in 190 whole MMs using synchrotron computed microtomography (SCMT). Both the section and the SCMT images show that sulfides melt, coalesce, and migrate to the MMs surface. The decomposition of sulfides may occur during all these stages. Given the sulfide morphologies and compositions that we see in section, we think the breakdown of Ni sulfides produces the FeNi beads. The SCMT images show that metal beads are common in melted MMs, >50% have them. Vesicles in porphyritic and scoriaceous MMs are also probably formed as sulfides decompose. Not only do sulfides abut the vesicles but also the temperatures at which sulfides decompose overlap those at which MM surfaces first melt and temporarily seal, suggesting that S gases could produce most of these vesicles. As the vesicle shapes and patterns of distribution differ among MM classes, tomography can be used to nondestructively screen for specific types of MMs. Tomography is a powerful tool for visualizing the three‐dimensional distribution of metal beads, sulfides, mean densities, and vesicles in MMs.