Triple iron isotope constraints on the role of ocean iron sinks in early atmospheric oxygenation

Abstract

The iron did it What factors controlled the accumulation of atmospheric oxygen gas (O 2 ) early in the history of Earth? Heard et al. used high-precision iron isotopic measurements of Archean-Paleoproterozoic sediments, with ages between 3.8 billion and 2.3 billion years ago, and laboratory data about synthetic pyrites to show that pyrite, or iron sulfide, burial could have resulted in net O 2 export. These reactions therefore may have contributed to early episodes of transient oxygenation before the Great Oxidation Event that began about 2.4 billion years ago. Science , this issue p. 446