[Physicochemical analysis of formation and self-organization of the components of the archaic cycle of CO2 fixation in hydrothermal systems].

The physicochemical analysis of parageneses, which is based on the method of thermodynamic potentials, has been applied to study the organic compounds of the system C-H-O, in particular the components of the biomimetically constructed cycles of chemoautotrophic fixation of carbon dioxide, e.g., the reducing cycle of citric acid, 3-hydroxypropionate cycle, and acetyl-CoA pathway. The thermodynamic analysis of the redox mode at different pressures and temperatures has allowed one to isolate a hydrocarbon-organic system capable to independently generate acetate and succinate upon oxidation of deep hydrothermal hydrocarbon fluids emerging on the sea surface. The area of thermodynamic stability (facies) of the hydrothermal system has been determined, which corresponds to the conditions of generation and self-organization of the components of archaic fixation of CO2. A unified system of archaic fixation of CO2 as a combination of the reducing cycle of citric acid, 3-hydroxypropionate cycle, and acetyl-CoA pathway has been proposed, which contains a succinate-fumarate core capable of switching the electron stream in the forward or reverse direction, depending on the redox potential of the surrounding geochemical environment. The geochemical redox mode, which depends on temperature, the structure of a hydrothermal fluid, and the mineral environment, determines the stability of the components of the archaic fixation of CO2 in paragenesis with hydrocarbons and the probability of the self-organization of the cycle.