Origin of light hydrocarbon gases from the Matsukawa geothermal area in Japan
1992; Elsevier BV; Volume: 94; Issue: 4 Linguagem: Inglês
10.1016/s0009-2541(10)80034-8
ISSN1872-6836
AutoresYasuhiro Kiyosu, Noriko Asada, Yutaka Yoshida,
Tópico(s)Atmospheric and Environmental Gas Dynamics
ResumoLight hydrocarbon and isotope compositions of methane were analyzed in well steam samples from the Matsukawa vapour-dominated type geothermal system. Alkanes (C1-C4) and alkene (C2) were detected in all samples. Light hydrocarbon contents of CO2-type steam are slightly higher than those of CO2-H2S-type steam. The isotope composition of methane and the relationship between methane/ethane ratio and δ13C-value of methane suggest that these light hydrocarbon gases are mixtures of thermogenic and abiogenic components. The abiogenic hydrocarbon may be attributed to magmatic hydrocarbon gases equilibrated with carbon dioxide at fo2 defined by the fayalite-magnetite-quartz buffer (FMQ).
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