Beta track autoradiography and infrared spectroscopy bearing on the solubility of CO2 in albite melt at 2 GPa and 1450� C

Abstract

Albite glasses with 0.5–2.0 wt.% CO2 synthesized at 2 GPa and 1450° C, previously analyzed by beta track autoradiography (Tingle 1987), have been analyzed by infrared spectroscopy. Values of CO2 concentration determined by the beta track technique are 10–50% greater than the amount of CO2 added to the sample. Values determined by infrared spectroscopy match the loaded CO2 contents, substantiating the existence of a previously unrecognized error in the beta track technique. Concentrations, and hence solubilities, in albite determined by infrared spectroscopy are more accurate than those determined by beta track autoradiography. Values obtained by the beta track technique for diopside are 10% lower than the loaded CO2 contents (Tingle 1987) and suggest that the systematic error may be dependent on composition and/or density.