Effect of Hydrous Pyrolysis on the Distribution of Carbon and Hydrogen Isotopes between Fractions of Organic Matter. The Nature of Oil Seeps in the Uzon Caldera, Kamchatka, Russia

— The paper presents data on the transformations of oil from seeps in the caldera of Uzon volcano under the effect of hydrous pyrolysis at a temperature of 350°C in an argon and oxygen atmosphere. The carbon and hydrogen isotopic-fractionation characteristics (IFC) are proved to reflect processes occurring in the organic matter at its hydrous pyrolysis in oxidizing and neutral environments. Similarities in configuration are detected between the carbon IFC of Uzon oil seeps, Bogachevskoe field, and the biota of hydrothermal springs. The hydrogen IFC are of more complicated form, perhaps, because of exchange processes in the hydrothermal water. It is hypothesized that oil seeps in the interiors of the Uzon caldera can provide material for the origin of oil at the Bogachevskoe field. At the same time, it cannot be ruled out that hydrothermal water circulating in the caldera of Uzon volcano brings the material of the Bogachevskoe oil to the surface.