Isotopic data of H₂-rich gas from ophiolitic, intracontinental represented in different graphs (Abrajano et al., 1988; Etiope et al., 2011; Lévy et al., 2023; Prinzhofer et al., 2018; Randazzo et al., 2021; Sherwood et al., 1988; Sherwood Lollar et al., 1993, 2007, 2008; Truche et al., 2018 Vacquand et al., 2018) compared to MOR (Charlou et al., 1996; Proskurowski et al., 2006, 2008) and volcanic/geothermal data (Arnason, 1977; Caliro et al., 2015; Darling and Talbot, 2003; Kiyosu, 1983; Ricci et al., 2022; Taran et al., 2010). (a) δD of H₂ for the different systems. (b) δD and δ¹³C of CH₄. We observe different zones related to a specific source using boundaries from Etiope (2017) and Xia and Gao (2022). (c) ε notation of H₂-H₂O and CH₄-H₂O. This graph is useful to observe if the system is at thermodynamic equilibrium and to use the different couples as geothermometers if possible. (d) The R/Ra ratio allows for defining the crustal or mantellic contributions.