Original paper

Sublimate speciation at Mutnovsky volcano, Kamchatka

Zelenski, Michael; Bortnikova, Svetlana

Abstract

Sublimates from high-temperature (470-507°C) gases at Mutnovsky volcano in southern Kamchatka were collected in silica glass tubes. Only particles of altered rocks were found in a transparent zone above 480°C. From 480 to 120°C, Fe and Cd sulphides with or without NaCl change to Cd-Pb-Bi and Pb-As-Bi sulphosalts, Pb-As and Bi sulphohalides, Cd, Pb, Tl halides, and an amorphous As-S compound. Sublimates are especially enriched in cadmium, thallium and iodine. Two new Cd-bearing sulphosalts Cd4PbBi12(S, Se)23 and CdPb4Bi6(S, Se)14 containing respectively 9 and 4 atomic% Cd were described. Tl occurs as three different halides. Seven phases contain iodine as a major or minor component; four of them additionally contain bromine. Crystal sizes, shapes and quantity within deposition intervals vary according to nucleation conditions. Mineral assemblages in natural fumarolic incrustations partly repeat the sequence observed in silica tubes.

Keywords

sublimatesmutnovsky volcanovolatile transportcd sulphosaltstl- i - bearing phases