The Chemical and Phase Composition of High Temperature Sublimates: Avachinsky Volcano, Kamchatka

This paper presents the results of a study of sublimates (mineral deposits from volcanic gases) that have been collected in silica tubes placed at high-temperature vents in the Eastern Fumarolic Field of Avachinsky Volcano, Kamchatka in 2013–2023. The ICP-MS and ICP-AES methods were used to obtain the concentration distributions for 62 elements throughout the tube lengths, i.e., along the temperature gradient. A total of 35 sublimate phases corresponding to naturally occurring minerals have been identified, in addition to 7 sublimate phases for which there are no naturally occurring analogues, or they are still unknown. The overall mineral sequence with decreasing temperature is as follows: Na and K halogenides; Na, K, and Ca sulphates; sulfides; As–S amorphous glass, and Tl, Pb, and Bi halogenides. The most abundant phases are As–S glass, SiO₂ (cristobalite), NaCl, KCl, Na₂SO₄‒K₂SO₄; rare phases: KCdCl₃, K₂Pb(SO₄)₂, Tl(I, Cl, Br), Pb₂Tl(Cl, I, Br)₅, PbTl₃(Cl, I, Br)₅, Pb(Cl, I, Br)₂, Tl₃BiI₆, ReS₂, the sulfides of Pb–Zn–Cd–In and AgI.