Vapor Pressure, Vapor Composition and Fractional Vaporization of High Temperature Lavas on IoObservations show that Io's atmosphere is dominated by SO2 and other sulfur and sulfur oxide species, with minor amounts of Na, K, and Cl gases. Theoretical modeling and recent observations show that NaCl, which is produced volcanically, is a constituent of the atmosphere. Recent Galileo, HST and ground-based observations show that some volcanic hot spots on Io have extremely high temperatures, in the range 1400-1900 K. At similar temperatures in laboratory experiments, molten silicates and oxides have significant vapor pressures of Na, K, SiO, Fe, Mg, and other gases. Thus vaporization of these species from high temperature lavas on Io seems likely. We therefore modeled the vaporization of silicate and oxide lavas suggested for Io. Our results for vapor chemistry are reported here. The effects of fractional vaporization on lava chemistry are given in a companion abstract by Kargel et al.
Fegley, B., Jr. (Washington Univ. Saint Louis, MO, United States)
Schaefer, L. (Washington Univ. Saint Louis, MO, United States)
Kargel, J. S. (Geological Survey Flagstaff, AZ, United States)