Аннотация:We calculated reaction flow in the closed system “0.495 М NaCl and 0.0194 M NaHCO3 aqueous solution + olivine (Fo91)” at temperatures 200 ºC and 320ºC and pressure 350 bar. The water/rock ratio, temperatures and pressure, the chemical composition and grain size of olivine, the chemical composition of aqueous solution, as well as duration of interactions were the same as in the experiments, described in (McCollom et al., 2016; McCollom, 2016). The results of calculations were compared with experimental results. The newly formed mineral assemblage in both cases consisted of highmagnesian serpentine and brusite, magnetite, and of a small amount of magnesite at 200ºC. The calculated rate of olivine serpentinization was close to the experimentally observed rate.