Rapid oxidation of mercury (Hg) at volcanic vents: Insights from high temperature thermodynamic models of Mt Etna's emissions

► Volcanic Hg(0) (i.e., Hg(g)) may be rapidly oxidised to Hg(II) (as HgCl2(g)) at the vent. ► Hg(II) production at volcanic vents is enhanced in lower temperature, HCl-rich magmatic gases. ► Near-source Hg speciation can be explained without invoking rapid, low temperature oxidation.