Extended Data Fig. 6: Porewater methane-sulfate concentrations and methane δ13C signatures.
From: Deglaciation drove seawater infiltration and slowed submarine groundwater discharge
Methane and sulfate profiles indicate the presence of sulfate-methane transition zones (b and c), or indicate that the SMTZ is situated deeper in the sediments (a and d). Low δ13CCH4 signatures suggest a biogenic origin of the methane (e). Degassing of CH4 during core recovery cannot be ruled out, hence actual CH4 concentrations are likely higher. The error bars in (a–d) represent the combined percent error range resulting from porosity uncertainties and the standard deviation of the 1% CH4 standard (n = 4). The error bars in (e) represent the standard deviation derived from the reference gas (n = 8).
