Production of Neoproterozoic banded iron formations in a partially ice-covered ocean

Abstract

The meridional extent of marine ice during the Neoproterozoic snowball Earth events is debated. Banded iron formations associated with the Sturtian glaciation are considered evidence for a completely ice-covered, ferruginous ocean (hard snowball). Here, using an ocean general circulation model with thick sea glaciers and Neoproterozoic biogeochemistry, we find that circulation in a partially ice-covered ocean (soft snowball) yields iron deposition patterns similar to the observed distribution of Sturtian banded iron formations. Neoproterozoic banded iron formations formed in partially glaciated oceans where iron-rich and oxygenated water masses met, according to ocean modelling.