| 研究実績の概要 |
Homogeneous glasses covering a range of water and carbon dioxide concentrations were produced for use as standards for volatile analysis by Fourier Transform Infrared spectroscopy (FTIR) and Secondary Ion Mass Spectrometry (SIMS). It was decided to focus on producing synthetic glasses, rather than utilising natural samples, because of the increasing recognition that even nano-scale crystals and other variations that occur in natural samples can cause problems for microanalytical techniques. Accordingly, homogeneous glasses were created using high pressure and temperature apparatus that enable rapid quenching to glass. Sample pressure and temperature conditions were chosen to give a good range of volatile contents for analytical calibrations, but also to add to existing volatile solubility datasets. In particular, these data provide better constraints for volatile solubilities in pressures relevant to the shallow volcanic conduit or eruptions occurring under ice or water. Volatile contents were analysed by FTIR, and will be confirmed by future manometry analyses. FTIR data have also been used to examine the cause of variation in 'silicate peaks' in transmission spectra, their implications for accurate measurement of molecular water in the mid-IR range, and their use for determining glass composition and thickness.
|
