Title: Periodic ocean oxygenation events during the mid-Ediacaran
Source: Nature Geoscience
Authors: Zi-Heng Li, Zhong-Qiang Chen, Stuart J. Daines, Feifei Zhang & Timothy M. Lenton
Published: 06 January 2026
Link: https://doi.org/10.1038/s41561-025-01883-1
Abstract:
The Ediacaran Gaskiers Glaciation (579.78–579.44 million years ago) is the last major climatic event of the Neoproterozoic, but the contemporaneous ocean redox conditions remain unclear. Here we conducted carbon–uranium–sulfur isotopic (δ13Ccarb–δ238Ucarb–δ34SCAS) and elemental analyses on marine carbonate samples from the glacial-to-deglacial succession (equivalent to the Gaskiers Glaciation successions) of the Egan Formation in northwestern Australia. Negative δ13Ccarb and positive δ238Ucarb excursions paired with δ34SCAS and cerium anomaly profiles reveal an extensive ocean oxygenation event. The Gaskiers ocean oxygenation event is the middle of three such transient mid-Ediacaran events, occurring roughly 5 million years apart. Using a model for the coupled biogeochemical cycles of phosphorus, oxygen and carbon, we show that these periodic ocean oxygenation events, associated δ238Ucarb variations and part of the δ13Ccarb variation can be explained by a self-sustaining oscillation in the Earth system. An increase in the organic carbon burial flux plausibly linked to eukaryote evolution at the time could have tipped the Earth system from a stable anoxic ocean regime to an unstable oscillatory regime. A later further increase in organic carbon burial flux could have tipped the system into a stable, modern-like oxic ocean regime.
