9307389 Kerrick The objective of this exploratory project is to develop a microbeam technique (~40 um spot size) for the in situ analysis of ferric and ferrous iron in silicate minerals and glasses in polished thin sections. The proposed technique involves analysis by x-ray photoelectron spectroscopy (XPS) of a fresh surface produced by cleaving or scraping the material of interest within the high vacuum sample chamber. Successful development of the technique would enable geoscientists to study the spatial variations of feric iron in compositionally zoned minerals, and it would eliminate the need for sample preparation that is both time-consuming and potentially oxidizing. The analytical results would find application in the study of redox processes and in thermobarometry of metamorphic rocks.
