Abiotic anoxic iron oxidation, formation of Archean banded iron formations, and the oxidation of early Earth

Iron in the early anoxic oceans of Archean age (4000-2500 million years ago) is believed to have been oxidized form banded iron formations (BIF). Previously, it has proposed that was either by free oxygen, H2O2, microbial oxidation, or photo-oxidation. However, these mechanisms are difficult reconcile with evidence for at time having largely devoid dissolved oxygen and oxidants, together rarity remains BIF restrictively slow rates Experiments reported here show ferrous readily oxidizes analogs seawater following precipitation hydroxide. Once precipitated, hydroxide undergoes decomposition elemental reacts water room temperature ferric release hydrogen gas. The may then be incorporated into green rust, a mixed ferrous-ferric phase ages minerals commonly found BIF. Our finding suggests oxidation contributed formation oxide-facies BIF, especially Algoma-type likely formed semi-restricted basins where saturation more easily achieved. Additionally, would Earth's as result escape space, thus providing new insights environmental biological conditions on Earth.