Redox texture of the Archean atmosphere and ocean
Our views on the redox state of the early Earth have gone through turmoil over last 3 decades. The paradigm of the Archean anoxic atmosphere and ocean that emerged in 1920’s and further strengthened in 1960’s was critically challenged in 1980’s and 1990’s. Studies of multiple S isotopes in Archean sulfate and sulfide minerals addressed some of the latter concerns and constrained the irreversible oxygenation of the atmosphere between ~2.45 and 2.32 Ga. Two important changes in our understanding of the early Earth’s redox evolution happened in the last decade: first, evidence for oxygenated, local or global, transient or ramping up, surface environments was discovered, and second, a model for recycling of mass-independent fractionation of sulfur isotopes after the rise of atmospheric oxygen was put forward. Both of these developments challenge our definition of the Great Oxidation Event. We invite contributions to this session that would present new data, results of modelling, or review our understanding of the redox texture in the Archean surface environments.
Andrey Bekker, Kurt Konhauser and Benjamin Eickmann