Fig. 3: Geochemistry of the gas emitted from the Borealis mud volcano.
From: Sanctuary for vulnerable Arctic species at the Borealis Mud Volcano
a Stable carbon (δ13C) and hydrogen (δD) isotope composition of methane from headspace gas analysis. Sample data from Borealis MV are reported in yellow starts, and for comparison, other high-latitudes cold seeps (location in Fig. 1) are reported: from Prins Karl Forland in white square71, from Leirdjupet Fault Complex (Leirdjupet FC) in grey hexagon72, from Håkon Mosby Mud Volcano (HMMV) in white circle73 and from Vestnesa Ridge (Vestnesa) in green diamond7. Genetic fields of hydrocarbons (CR-CO2 reduction, F—methyl-type fermentation, EMT—early mature thermogenic gas, OA—oil-associated thermogenic gas, LMT—late mature thermogenic gas) after36. b Plot of δ13C-CH4 versus the composition of light hydrocarbon components (C1/(C2 + C3) ratio). Grey arrows indicate the main processes affecting the isotopic and molecular compositions of gases.
