Trace Elements and Minerals in Fumarolic Sulfur: The Case of Ebeko Volcano, Kuriles

Figure 10

Chemical processes in low-temperature sulfur fumaroles. Fumarolic gases (mainly H₂O, CO₂, SO₂, H₂S, and HCl) carry volatile metal species and some amount of rock aerosol. At the fumarole vent, the temperature abruptly decreases and volatile species condense, forming solid phases and acid condensate that is enriched in HCl, while H₂S mainly escapes. Sulfur is precipitated due to the reaction between H₂S and SO₂ and the partial oxidation of H₂S. Hot acid condensate can attack rock particles, extracting metals. Then, the condensate cools to ambient temperature and the chlorides of metals (e.g., CuCl₂, FeCl₂) from the acid solution react with H₂S to form insoluble sulfides. Petrogenic elements do not form sulfides, and their chlorides are washed away from incrustations by atmospheric precipitates.