No abstract

Thermodynamic calculations are made for the reactions of inorganic hydrocarbons under redox condi tion governed by a variety of mineral buffer systems. The results indicate that the amounts of alkanes and alkene depend essentially on the oxygen fugacity rather than temperature or other factors such as fH2o and fco2 . The concentrations of volcanic light hydrocarbons are probably controlled by redox conditions during the discharge process as well as equilibrium with magma.

No abstract

Three fumarolic gases, both gas and liquid phases, from the Kakkonda (Takinoue) geothermal area, northern Japan, were analyzed with a gas chromatograph-mass spectrometer to confirm the presence of C5+ hydrocarbons in the geothermal fluid of this area. C5+ hydrocarbons found in the analyses were mainly alkanes (C5-C15), aromatics (C6-C12) and cycloalkanes (C6-C8). Alkanes in the gas phase of one of the three samples show CIp-C1, predominance, which has not been observed in other geothermal fields before. This clearly shows that compositions of heavier hydrocarbons from fumaroles in this area are not uniform. The variety suggests that up-flows in this geothermal circulation system take hydrocarbons with various degrees of thermal degradation up to the surface.