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