Fig. 1. Requisite seawater [Mo] and Mo input to satisfy mass balance as indicated by ancient shales from 3.2 to 2.0 Ga.
(A) Distribution of the seawater Mo concentrations of possible mass balance solutions, where concentrations are reported in (M × 109) (B) Distribution of possible mass balance solutions where Mo input (Rin) is plotted as a percentage of the modern riverine Mo flux ([(mol/year)MODEL]/[(mol/year)MODERN] × 100). Boxes represent the central quartiles of the mass balance solutions (Q2 and Q3) and include a horizontal line to indicate the median. Whiskers represent mass balance solutions that occur within 1.5 quartiles of the boxes; solutions that fall outside this range are plotted as points. Notably, the minimum Mo required of each solution set increases through time.