(Great Oxidation Event) Stage 3 (1.85–0.85 Ga): O 2 starts to gas out of the oceans, but is absorbed by land surfaces. The Great Oxidation Event (GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, Oxygen Crisis or Oxygen Holocaust,[3] was a time interval during the Earth's Paleoproterozoic era when the Earth's atmosphere and shallow seas first experienced a rise in the concentration of free oxygen. [24]Geological evidence [ edit ]Evidence for the Great Oxidation Event is provided by a variety of petrological and geochemical markers that define this geological event. [34][28][36]Isotopes [ edit ]Some of the most persuasive evidence for the Great Oxidation Event is provided by the mass-independent fractionation (MIF) of sulfur. The Great Oxygenation Event can then be understood as a transition from the lower to the upper steady states.