Decipherment of important reoord concerning the earth and planet activity that remains in local structure of trace elements

这项研究是对保留在局部微量元素结构中的有关地球和行星活动的重要记录的一种尝试。通过X射线吸收光谱和X射线衍射法获得了关于特定元素周围的精确局域结构的信息。物理性能测量、电子态测量和结构分析密切联系在一起，以研究极端条件下熔体、非晶态和晶体材料的细节。这些实验是在现场进行的，使用了世界顶尖的设备，如Spring-8同步加速器设施。以建立地球内部等多元素、多相的纳米级结构、宏观性质、结构和历史联系的理论为目标，利用XAFS光谱研究了K-T界面粘土中痕量元素的局部结构。在K-T界面粘土中，砷作为一种过富集元素占据了矿物的AS04四面体位置，通过与几种砷矿物的对比，XAFS谱的特征与As(+5)矿物的值符合得很好。Al_2SiO_5蓝晶石中的客体Fe元素具有较高的四价态，Fe-O键距为1.865(7)(A)，这是因为蓝晶石经历了高压和高氧化条件。研究了矿物中惰性气体的局部结构和反应性。在高温高压下合成了几种惰性气体掺杂矿物，并对其进行了质谱分析和X射线光电子能谱分析。有趣的是，惰性气体和邻近原子之间的原子距离似乎比简单吸附的情况下预期的距离要短。这些结果表明，惰性气体可能结合在相互作用比吸附更强的样品中和/或存在于主体矿物结构的内部位置。

This research is an attempt to read the important record concerning the earth and planet activity that remains in local structure of trace elements. Information on a precise local structure around a specific kind element is obtained by X-ray abscxption spectroscopy and the X-ray diffraction methods. Physical properties measurement, electronic state measurements and structure analyses are put into close contact to investigate details of the melts, amorphous and crystals materials under extreme conditions. The experiments are performed in-situ, by using world's top level equipments such as Spring-8 synchrotron facilities. The research aims the construction of the theory that links the nanometer-level structure, the macroscopic properties and the textures and history in multi element and multi phases such as the Earth's interior.Local structure of trace elements in K-T boundary clays was studied by XAFS spectroscopy. Arsenic as an excessively concentrated element occupies the As04 tetrahedral site of a mineral in K-T boundary clays and the characterization of XAFS spectra agree well with the values of As(+5)minerals according to the comparison with several types of arsenic minerals. The guest Fe elements in Al2SiO5 kyanite have higher-valence states of tetravalent and the Fe-0 bond distance is of 1.865(7)(A)because kyanite had been experienced the high pressure and high oxidized conditions. The local structure and reactivity of noble gas in minerals has been investigated. Several kinds of noble gas-doped minerals were synthesized under high pressures and temperatures and were subjected to mass spectroscopy and XAFS. Interestingly, the atomic distances between noble gas and neighboring atoms appeared to be shorter than the distances expected for the case of simple adsorption. These results suggest that noble gas might be bound in the samples with interaction stronger than the adsorption and/or exist in the internal sites of the structure of the host minerals.