Figure F4. Interpretative plot of molecular ratios of hydrocarbons vs. carbon isotopic compositions of methane in headspace gas recovered at Site 1146. Other data are from Matsumoto et al. (2000). 1 = the South China Sea (Site 1146); 2 = offshore Peru; 3 = offshore Oregon; 4 = Gulf of Mexico; 5 = Blake Ridge; 6 = the Sea of Okhotsk; 7 = the Caspian Sea.

Figure F4. Interpretative plot of molecular ratios of hydrocarbons vs. carbon isotopic compositions of methane in headspace gas recovered at Site 1146. Other data are from Matsumoto et al. (2000). 1 = the South China Sea (Site 1146); 2 = offshore Peru; 3 = offshore Oregon; 4 = Gulf of Mexico; 5 = Blake Ridge; 6 = the Sea of Okhotsk; 7 = the Caspian Sea.