Figure F28. Methane (C₁) concentrations, methane vs. ethane and propane ratios (C₁/C₂+C₃), and percent wetness ([C₂+C₃/C₁/C₂+C₃]100) from headspace gas analysis at Site 1170. Dashed lines delineate biogenic and thermogenic fields on the C₁/C₂+C₃ plot (Hinz et al., 1986), whereas the shaded area on the percent wetness plot marks values typical for economically viable gas reservoirs.