Spectroscopic studies of geological glasses and melts

火山的物理和化学行为在很大程度上取决于火山下面熔融物质或岩浆的性质。岩浆是硅酸盐熔体、晶体和溶解气体的混合物。熔体相起着重要的作用，因为它的结构影响着流变性、扩散和喷发方式等性质。然而，熔体的现场研究在技术上是困难的，而研究淬火的熔体或玻璃更容易。对熔体和玻璃结构的地质研究自30年代以来一直在进行，并在继续，美国、日本和欧洲的大型研究小组在这一领域积极开展研究。通常，简单的熔体组合物被制备并淬火成玻璃。所生产的玻璃具有与相应熔体非常相似的性质。这些玻璃然后通过复杂的仪器进行探测，对光谱数据的分析提供了关键信息，用来解释玻璃的形态、结构和配位。通过确定组成如何影响合成玻璃的结构性质，就有可能建立一个基础，在此基础上开发更复杂的自然系统的结构模型。在这里，我建议研究组成对1)O、B、Al、Fe和Ti等元素的配位的影响，2)不同碱(Li、Na、K、Rb)对扩展玻璃结构的影响，3)对熔体进行原位研究，试图观察结构随温度变化的变化，4)合成玻璃用于存放核废料的适宜性。这些项目涉及目前地质玻璃/熔体研究中明确界定的具体领域。很大一部分研究将在加拿大光源(CLS)进行，这是最近在萨斯卡通开放的国家同步辐射设施。我在将要使用的仪器和技术方面有丰富的经验，并在玻璃/熔体研究中的应用方面获得了国际声誉。此外，一些拟议的研究是与IPGP(巴黎)和IMPMC(巴黎)的同事合作进行的，并将利用加拿大以外的仪器和同步加速器设施。

The physical and chemical behaviour of volcanoes depends to a great extend on the properties of the molten material or magma beneath the volcano. Magmas are mixtures of silicate melt, crystals and dissolved gases. The melt phase plays an important role because its structure influences properties such as rheology, diffusion and eruptive style. However, in situ studies of melts are technically difficult and it is easier to study the quenched melt or glass. Geological research into the structure of melts and glasses has been ongoing since the 30s and continues, with large research groups in the USA, Japan, and Europe actively in this area. In general, simple melt compositions are prepared and quenched to glass. The glasses produced have properties closely analogous to the corresponding melt. These glasses are then probed by sophisticated instrumentation and analysis of the spectroscopic data provides key information with which to interpret the speciation, structure and coordination of the glasses. By establishing how composition affects the structural properties of the synthetic glasses it is possible to establish a basis upon which to develop structural models of more complex natural systems. Here I propose to study the influence of composition on 1) the coordination of elements such as O, B, Al, Fe and Ti, 2) the influence of different alkalis (Li, Na, K, Rb) on the extended glass structure, 3) perform in-situ studies on melts and attempt to observe structural changes with changing temperature and, 4) the suitability of using synthetic glasses to host nuclear waste products. These projects address specific well-defined areas of current interest in geological glass/melt research. A significant portion of the research will be carried out at the Canadian Light Source (CLS), the recently opened national synchrotron radiation facility in Saskatoon. I have extensive experience with the instrumentation and techniques that will be employed and have developed an international reputation in their application to glass/melt research. In addition, some of the proposed research is collaborative with colleagues at IPGP (Paris) and IMPMC (Paris) and will utilise instrumentation and synchrotron facilities outside of Canada.