Издатель: A.A. Balkema , Место издания: Lisse , Год издания: 2001

The results of a detailed geochemical and mineralogical study of andesite alteration at the Northeast fumarole field of volcano Ebeko are submitted. It is shown that the results of a developed physical-chemical model describes adequately the features of secondary mineral formation depending on changing composition of thermal waters and on varying water/rock ratio. As a whole, at increase of this ratio, acid solution/andesite system is characterized by the change of pH from 9.36 to 0.97, close to observable on fumarole field. As this takes place, the sequential leaching of pairs of Na and Ca, then Mg and Fe, and Al and Si goes on. The concentration of last part in solution is defined by the stable quartz-alunite association.