how many years can carbon dating go back - Dating the rise of atmospheric oxygen bekker
Considering these redox potential constraints, Mn oxidation is an attractive photosynthetic donor on a trajectory to oxidizing water (16–18).
An initial manganese-oxidizing photosystem also explains both why the only known biological system that can oxidize water originally procures electrons from Mn and why WOC assembly begins with Mn oxidation.
The behavior of the ancient Mn cycle is useful because it is uniquely sensitive to high-redox-potential oxidants like O-derived species like superoxide and hydrogen peroxide) or a high-potential photosystem (35, 36).
It is notable that although Fe was removed from shallow water via oxidation processes in Archean marine environments, the same was not true for Mn (20, 37).
Currently, sulfur isotope measurements have constrained the rise of oxygen and minimum age for the origin of cyanobacteria as having occurred between 2.45 and 2.32 Ga (1, 2)—an interval supported by a broad range of geologic evidence (19, 25, 33).