Composition and Distribution of Saturated Hydrocarbons in the Thermal Waters and Vapor–Water Mixture of the Mutnovskii Geothermal Field and Uzon Caldera, Kamchatka

— The paper presents data on the composition and molecular-mass distribution of saturated hydrocarbons in sterile vapor–water mixture from wells and in high-temperature springs in the Mutnovskii hydrothermal area and Uzon caldera. The condensate of the vapor–water mixture and thermal waters from the Mutnovskii area contain low-molecule n -alkanes, which were generated by thermogenic processes. The boiling mud pot of the Donnoe fumarole field typically contains hydrocarbons whose origin is likely related to thermocatalytic transformations of the biomass of thermophilic microorganisms. A separate type of the molecular-mass distribution is typical of the geyser in the caldera of Uzon volcano: this material contains n ‑alkanes, which were generated by two processes: chemical re-synthesis of floral organic remnants and biogenic synthesis with the probable involvement of bacteria and algae.