Noble gas fractionation during the degassing of melts

Abstract

A simple model for equilibrium noble gases partitioning amongst solid, melt, and gas phases, and extraction of the gas (vesicles) from the system was used to study the relationships between the rate of noble gas fractionation and parameters controlling the degassing process. The following results are inferred: (i) the lower the ratio of a gas-phase volume (vesicles) divided by the volume of melt, the higher the degree of noble gas fractionation in the melt; (ii) relative excess of both lighter (Ne) and heavier (Xe) noble gases over Ar occurs providing a high solid/melt partition coefficient for Xe and a small melt fraction. © 1993, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.