Sulphur solubility experiment

Thomas Ulrich

Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia

 

The aim of these experiments was to determine the S solubility in respect to oxygen fugacity in silicic melt (dacitic composition). The experiments will give insight into the S behaviour during magma evolution and volcanic eruptions. It was found that the S solubility generally decreases with increasing oxygen fugacity. The solubilities were lower in hydrous experiments compared to dry experiments and thus indicate that S partitions strongly into a volatile phase in hydrous experiments. These results corroborate findings of earlier studies that it is likely that S is stored in a coexisting fluid phase together with melt beneath active volcanoes. During a volcanic eruption this fluid will be expelled and contributes to the large amounts of S that can be transported into the atmosphere and can explain the S budget between atmospheric S measurements and solubility estimates from S determinations in pre-eruptive melt inclusions.