Figure 6: O2 fluxes versus duration of the sulfur isotopic excursion.

O2 fluxes produced by a 50% distillation of the oceanic sulfate reservoir by sulfate-reduction and pyrite burial as a function of the duration of the sulfur isotopic excursion. For the bottom curve the starting concentration of sulfate was of 0.4 mM, for the top one it was of 10 mM. The y axis to the right corresponds to the proportion of O2 produced compared with the present production of O2 attributed to pyrite burial per year (PPO/yr), estimated at 7 Tmol per year by Holland et al.44