Sulfur isotopic compositions of fumarolic and plume gases at Mount Etna (Italy) and inferences on their magmatic source

New research reveals that sulfur isotopic compositions (δ34S) of magmatic gases at Mount Etna are systematically lower than those dissolved in melt, suggesting a distinct magmatic source with δ34S constrained to 1.0 ± 1.5‰. The study analyzed fumarolic and plume gases collected between 2008–2009, comparing them with sulfur in primitive melt inclusions from 2002 lava and whole rocks erupted over the past two millennia. Modeling isotopic fractionation during magma degassing indicated that the magmatic system is significantly more oxidizing (ΔNNO ≥ 1) than previously thought, explaining why SO2 dominates in Etna's plume. This finding challenges prior assumptions about sulfur species in oxidized basaltic melts and provides insights into volcanic processes shaping this UNESCO World Heritage Site.

Liotta, M., Rizzo, A., Paonita, A., Caracausi, A., & Martelli, M. (2012). Sulfur isotopic compositions of fumarolic and plume gases at Mount Etna (Italy) and inferences on their magmatic source. Geochemistry, Geophysics, Geosystems, 13(5). Portico. https://doi.org/10.1029/2012gc004118