The Arena Fm is a formation of shales that are situated between two glacial deposits that are thought to represent two global glaciation events called Snow Ball Earths. Competing hypotheses try to explain the second big rise in oxygen concentrations that occured around this time, including attributing it to these two global glaciation events. Through our analysis of the Arena Fm, we constrained the redox conditions of the Arena Basin. Our results showed an anoxic ocean, suggesting that ocean oxygenation had not occurred following the first of the two global glaciation events.

See more in Scheller et al. (2018). Ocean redox conditions between the snowballs – Geochemical constraints from Arena Formation, East Greenland. Precambrian.