A model for Cryogenian iron formation

作者：Cox Grant M; Halverson Galen P; Poirier Andre; Le Heron Daniel; Strauss Justin V; Stevenson Ross

来源：Earth and Planetary Science Letters, 2016, 433: 280-292.

DOI：10.1016/j.epsl.2015.11.003

• iron formation
• snowball Earth
• iron isotopes
• neodymium isotopes
• Cryogenian

The Neoproterozoic Tatonduk (Alaska) and Holowilena (South Australia) iron formations share many characteristics including their broadly coeval (Sturtian) ages, intimate association with glaciogenic sediments, and mineralogy. We show that these shared characteristics extend to their neodymium (epsilon(Nd)) and iron isotope (delta Fe-56) systematics. In both regions delta Fe-56 values display a distinct up-section trend to isotopically heavier values, while eNd values are primitive and similar to non-ferruginous mudstones within these successions. The delta Fe-56 profiles are consistent with oxidation of ferruginous waters during marine transgression, and the epsilon(Nd) values imply that much of this iron was sourced from the leaching of continental margin sediments largely derived from continental flood basalts. Rare earth element data indicate a secondary hydrothermal source for this iron.

• 出版日期2016-1-1