Extreme ocean anoxia during the Late Cryogenian recorded in reefal carbonates of Southern Australia

Abstract

The Neoproterozoic was a time of great change in the Earth's surface and marine environments, including extensive climate variability, the widespread oxygenation of the oceans and the accompanying rise of animal life. However, the timing of ocean oxygenation remains uncertain, particularly in regard to Cryogenian seas, which were disrupted by large periods of global glaciation. Interglacial Cryogenian reef complexes in the Northern Adelaide Fold Belt of Australia contain abundant primary marine dolomite cements. These cements have well-preserved textural and growth zonation, indicating they preserve their original marine chemistry and can be used as geochemical proxies for Late Cryogenian pa..