Phase and Chemical Composition of High-Temperature Sublimates of Avachinsky Volcano (Kamchatka)

This work presents results of studying sublimates (mineral phases deposited from volcanic gases) that were collected in silica glass tubes placed in high-temperature fumaroles at the Eastern fumarole field of Avachinsky volcano (Kamchatka) in 2013–2023. The concentration distributions of 62 elements along the length of the tubes (along the temperature gradient) were studied by ICP-MS and ICP-AES methods. 35 phases of sublimates corresponding to natural minerals and 7 phases of sublimates for which no natural analogues are known were diagnosed. A general mineral sequence with decreasing temperature is as follows: Na and K halides; Na, K, Ca sulfates; sulfides; X-ray amorphous As-S glass and Tl, Pb, Bi halides. The most common phases are As-S glass, SiO, NaCl, KCl, NaSO–KSO; rare phases are KCdCl, KPb(SO), Tl(I,Cl,Br), PbTl(Cl,I,Br), PbTl(Cl,I,Br), Pb(Cl,I,Br), TlBiI, ReS, Pb-Zn-Cd-In sulfides and AgI.