Behavior of volatile elements at the early stage of our solar system - Exploration of Q, the main host phase of noble gases in meteorite -

本研究的目的是检验“等离子体模型”（或“大坂模型”，其中Q是太阳前金刚石的表面层和在等离子体条件下电离的惰性气体注入的碳相）的Q。通过本研究发现以下几点。(1)Buss等（1996）报道，稀有气体随着岩石类型的增加而减少，HL组分比Q组分更容易受到热变质作用的破坏。而在热水化蚀变作用中，Q组分比HL组分更易受到损伤，这与热变质作用的趋势正好相反。(2)首次找到了一种用纯物理方法分离阿连德陨石富气组分的方法。我们将这种方法应用于两个普通的晶体。我们可以得到类似的分数为这些陨石，但没有丰富的惰性气体。(3)对铁陨石石墨球中的惰性气体进行了测量，发现石墨球中含有Q，并发现了一种新的组分，称为“El Taco”。（4）在惰性气体气氛下合成了SiC，并考察了SiC对惰性气体的捕集效率。(5)对物理分离得到的阿连德漂浮部分进行了粒度和密度分离。稀有气体测量表明，稀有气体的密度分数为1.65± 0.04 g/cm^3。扫描微探针检测表明，这部分主要是碳。

Our aim of this study is to test the "Plasma model" (or "Osaka model" where Q is the surface layer of the presolar diamond and the carbon phase implanted by the noble gases ionized under plasma condition) for Q. The following things are found through this study.(1) Buss et al. (1996) reported that noble gases decreases with increasing petrologic type and that HL component is more easily damaged than Q to the thermal metamorphism. However, we found that Q is more easily damaged than HL component in the thermal hydrous alteration, which is just the opposite trend to the thermal metamorphism.(2) We firstly found a method to separate gas-rich fraction by purely physical mean for the Allende meteorite. We applied this method to the two ordinary chondrites. We could obtained the similar fraction for these chondrites, but there is no enrichment of noble gases.(3) We measured the noble gases in the graphite nodule of iron meteorite, and found that there are Q in the graphite nodule and that there is a new component called "El Taco Xe"/(4) We synthesized the SiC under noble gas atmosphere and examined the trapping efficiency of noble gases in SiC.(5) We made the size and density separation of the floating fraction of Allende which was obtained by the physical separation. The noble gas measurement showed that the noble gases were enriched in the density fraction of 1.65±0.04g/cm^3. The scanning microprobe examination shows that this fraction is mostly carbonaceous.