This project will investigate the structures of iron-bearing volcanic magmas under conditions of controlled temperature and oxygen pressure with Raman spectrometry. Glasses quenched from the high-temperature experiments will be analyzed by electron microprobe for bulk chemical analysis, by Raman spectroscopy for comparison with melts, by Mossbauer spectroscopy for determination of ferric iron and to observe iron structural trends, and by heavy liquid methods for characterization of their densities. The results of these experiments will help to determine the degree to which the structures of iron-bearing glasses are representative of those of the corresponding melts, and the degree to which the latter may vary in response to changes in composition, temperature, and oxygen fugacity. The results are expected to be of value in the fields of igneous petrology, volcanology, and materials science.
