Trace Element Emission by Fumaroles of Avachinsky Volcano (Kamchatka)

The trace element composition of high-temperature gases of Avachinsky volcano was investigated. For this purpose 25 samples of gas condensates and sublimates deposited in four quartz tubes were analyzed. The total average concentration of trace elements (excluding S, Cl, F, Si) in the condensates was 87 mg/L, reaching maximum value of 210 mg/L, with the predominance of B, K, Na, Br, and As. A large number of samples taken during 2013–2023 allowed us to evaluate the variations of element concentrations, their dependence on the fumarole temperature and the season of sampling. The magnesium-normalized enrichment factors made it possible to determine the elements transported in the plume as volatile compounds (S, Cl, Te, I, B, Br, Cd, As, F, Re, Se, Bi, Tl, Hg, Sn, Sb, Pb, etc.) and as silicate aerosol (Ti, Fe, Ga, Al, Ca, Mn, REE, etc.). Ore element concentrations in gases of Avachinsky volcano are similar to those of Mutnovsky volcano (Kamchatka) and are much lower than those of Kudryavy and Pallas Peak (Kuril Islands), volcanoes at the stage of stationary degassing, which can be explained by the higher HCl concentrations in the gases of the latter.