Origin of methane-rich natural gas at the West Pacific convergent plate boundary.

ABSTRACT: Methane emission from the geosphere is generally characterized by a radiocarbon-free signature and might preserve information on the deep carbon cycle on Earth. Here we report a clear relationship between the origin of methane-rich natural gases and the geodynamic setting of the West Pacific convergent plate boundary. Natural gases in the frontal arc basin (South Kanto gas fields, Northeast Japan) show a typical microbial signature with light carbon isotopes, high CH₄/C₂H₆ and CH₄/³He ratios. In the Akita-Niigata region - which corresponds to the slope stretching from the volcanic-arc to the back-arc -a thermogenic signature characterize the gases, with prevalence of heavy carbon isotopes, low CH₄/C₂H₆

SUBMITTER: Sano Y 

PROVIDER: S-EPMC5688071 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature