Fig. 2: Evolution of the dimensionless oxygenation parameter, Koxy.
From: Mantle data imply a decline of oxidizable volcanic gases could have triggered the Great Oxidation
Solid lines represent median values, and the shaded region bounds 5% to 95% probability quantiles. These are obtained by 10,000 times Monte-Carlo simulations. Gray dotted lines highlight Koxy = 1, above which the atmosphere is oxic; otherwise, it is anoxic. a Organic burial fraction is constant at 20%, and the secular increase in the oxygen fugacity of mantle in Fig. 1b is considered. b Both a change in organic burial fraction from Krissansen-Totton et al.24 and secular increase in the oxygen fugacity in Fig. 1b are considered. c Oxygen fugacity is assumed to be constant at three different levels (blue: FMQ-2, black: FMQ-1, orange: FMQ). The fluctuations come from imposed changes in organic burial fraction. In b, the parameter Koxy exceeds unity by ~2.5 Ga with >= 95% probability.
