How were marine environments across the Great Oxidation Episode?

We analyzed various isotopic systems in the Kuruman Formation. The results give insights on the modus-operandi of the Paleoproterozoic oceans.

 Summary

The Great Oxidation Episode (GOE) is a major reorganization process that took place during the Neoarchean and Paleoproterozoic periods, and unfortunately, its exact temporal evolution is entirely clear yet.  To that end, we analyze Δ33S and δ98Mo data from the Kuruman Formation to gain insights into its timing and nature. Our results show that atmospheric oxygen fluctuations exceeding the 10-7 present atmospheric levels threshold occurred within approximately ~2 Myr. Conversely, shallow oxygen-rich waters persisted for at least ~15 Myr, while deeper waters remained ferruginous and/or euxinic. These findings highlight the GOE's extensive duration and localized nature, comprising multiple events within specific time frames and geographical boundaries. Our study advances understanding of the GOE's temporal dynamics, contributing to comprehension of Earth's atmospheric and marine evolution. Finally, the relationship between the GOE and Paleoproterozoic glaciations requires further exploration, but it is clear that the final stage of the GOE closely followed these glaciations.