Onset of persistent surface ocean oxygenation during the Great Oxidation Event.

ABSTRACT: Free oxygen (O₂) first began accumulating in Earth's atmosphere shortly after the Archean-Proterozoic transition during the 'Great Oxidation Event' (GOE). The nature of surface ocean oxygenation at this time is, however, poorly quantified, limiting our understanding of planetary oxygenation thresholds. Geochemical records of global ocean redox may potentially shed light on this critical interval. Here, we show that vanadium (V) isotope ratios in 2.32-2.26-billion-year-old (Ga) shales from the Transvaal Supergroup, South Africa, capture a unidirectional transition in global ocean redox conditions shortly above the stratigraphic level marking the canonical rise of atmospheric O₂. Around 2.32 Ga, sedimentary sinks were dominated by anoxic environments that drove extensiv

SUBMITTER: Heard AW 

PROVIDER: S-EPMC12690087 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature