Figure 5

Schematic evolution of methane seepage at LFC after the LGM. (a) During the LGM, grounded ice sheet maintained gas hydrates stable for hundreds of meters below the seafloor. (b) The retreat of the ice sheet triggered hydrate destabilization and enhanced methane fluxes toward the seafloor causing the shoaling of the SMTZ. (c) An overall decrease in methane flux during the Holocene was recorded at both studied areas. PM = Ploughmark area; PK = Pockmark area. The modern SMTZs and paleo-SMTZs are highlighted in red and grey color, respectively. Not in scale.