Evolution of composition of high-temperature fumarolic gases from Kudryavyvolcano, Iturup, Kuril Islands: the thermodynamic modeling

Based on the chemical analyses of gases and condensates from high-temperatu re fumaroles of the Kudryavy volcano, we performed a thermodynamic simulati on of transportation and deposition of ore- and rock-forming elements in hi gh-temperature volcanic gases within a temperature range of 1373-373 K at 1 bar pressure. The results of our numerical simulation of mineral depositio n from gases are consistent with the data of field observations. Alkali and alkali earth metals, Ga, In, Tl, Fe, Co, Ni, Cu, and Zn are mainly transpo rted as chlorides in the gas phase. Sulfide and chloride forms are characte ristic of Ge, Sn, Ph, and Bi at intermediate and low temperatures. Be, Al, and Si migrate as fluorides and oxides, while As and Sb, as sulfides and ox ides. More complex, oxyfluoride and oxychloride species are typical of Ti, Zr, V, Mo, W, and Re. Cd (at high temperatures) and Hg (within the whole te mperature range) are transported in the neutral form. Our calculations reve aled some general regularities in the variation of element species in the g as phase at a low (1 bar) pressure versus thermodynamic conditions.