Fig. 3: Secular variations of P record and ocean chemistry through time.
From: A phosphate-rich marine reservoir in the redox stratified Ediacaran ocean
a P/Fe(100) molar ratios for Precambrian iron formations. b expanded view of P/Fe(100) molar ratios for Neoproterozoic (Tonian, Cryogenian and Ediacaran) iron formations. c Size of phosphorite deposits through the Neoproterozoic to Cambrian (900 to 500 Ma)22. d Estimated trajectory of oceanic sulphate concentrations through the Neoproterozoic to Cambrian55,56. e Schematic representation of the evolution of marine redox state through the Neoproterozoic to Cambrian based on compiled palaeoredox proxy records (adapted after ref. 57).
