Isotopic biomarker sulfur isotopes

Geochemical evidence suggests that there were delays of several hundred million years between the rise of oxygenic photosynthesis, the oxygenation of the atmosphere, and the oxygenation of the deep ocean. Photosynthesis (evidenced by cyanobacterial microfossils and biomarkers) rose as early as 3.5 Ga (billion years before present (Schopf, 1993)) and had been sofidly established by 2.7—2.5 Ga (Brocks et al, 1999 KnoU, 1996 Schopf, 1993 Summons et al, 1999). Data from red beds, detrital mineral deposits, and sulfur isotopes indicate the rise of atmospheric oxygen around 2.4 Ga (Bekker et al, 2004 Chandler, 1980 Des Marais et al, 1992 ... 

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