Non-equilibrium and unsteady fluid degassing during slow decompression

Decompression experiments were performed on corn syrup-water solutions in o rder to investigate the effect of viscosity on processes of vesiculation an d degassing at low to moderate degrees of volatile supersaturation. Repeat experiments demonstrated similar long term vesiculation behavior at moderat e decompression rates despite highly variable initial nucleation styles, Re sults suggest that magmas may not necessarily achieve chemical equilibrium by vapor exsolution and may require viscosity-dependent critical supersatur ations in order to vesiculate. Vesiculation also increased the ambient pres sure and decreased supersaturations, resulting in unsteady degassing.