Validity of Geochemical Signatures of Abiotic Hydrocarbon Gases on Earth

Appendix 1: Isotope fractionation in a flow under steady-state. Figure S1: Isotope distribution during methanogenesis and methanotrophy. Isotopologues with more than two substitutions are omitted.Appendix 2: Model details of the Xujiaweizi gas. Table S1: Reaction steps and rate constants for hydrogenolysis of C₂H₆ and C₃H₈ catalyzed by free radicals. Table S2: Parameters for the simulation to resemble Xujiaweizi gas.