Fig. 3: Comparison of average Mn oxidation state with atmospheric O2 reconstructions.
From: Evidence for the oxidation of Earth’s crust from the evolution of manganese minerals
A Graph of the average oxidation state of Mn according to Mn mineral occurrences (black squares, right vertical axis) over the most recent 1 billion years, overlain with reconstructions of atmospheric oxygen (left vertical axis) by Berner and Canfield14 (red line), Bergman et al.15 (green line), and the O2 concentration range including minimum, average, and maximum by Holland16 (blue lines). Uncertainties regarding the Mn oxidation state data points are standard deviations calculated (assuming a Poisson distribution of mineral-locality counts) as the square root of the sums of the variances of counts for the individual oxidation states according to propagation of errors. B Graph of the average oxidation state of Mn according to Mn mineral occurrences (black squares) over the most recent 1 billion years, overlain with reconstructions of atmospheric oxygen by Berner and Canfield14 (red line), Bergman et al.15 (green line), and the O2 concentration range including minimum, average, and maximum by Holland16 (blue lines), but with oxygen reconstructions shifted forward in time by 66.4 Myr. Note that when this time lag is accounted for, the average oxidation state of Mn in the geologic record displays a trend of minima and maxima that coincide closely with atmospheric oxygen concentrations.
