Mn enrichment in Archean sedimentary records implies Mn oxidation
Mn enrichment in Archean sedimentary records is primarily ascribed to Mn oxidation by free oxygen
Mn oxidation in Archean was achieved by anoxygenic photosynthetic microorganisms under anaerobic conditions
Mn oxide rarely survive during settling in an anoxic water column
Some oxidants may prevent Mn oxide from reductive dissolution during its settling in an anoxic water column
Redox proxies suggest an atmospheric oxygenation event occurred at ~3 Ga