|Author(s)||Heard Andy W.1, 2, Dauphas Nicolas1, 2, Guilbaud Romain3, Rouxel Olivier4, Butler Ian B.5, Nie Nicole X.1, 2, 6, Bekker Andrey7, 8|
|Affiliation(s)||1 : Univ Chicago, Dept Geophys Sci, Origins Lab, 5734 S Ellis Ave, Chicago, IL 60637 USA.
2 : Univ Chicago, Enrico Fermi Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA.
3 : CNRS, UMR5563, Geosci Environm Toulouse, F-31400 Toulouse, France.
4 : IFREMER, Unite Geosci Marines, F-29280 Plouzane, France.
5 : Univ Edinburgh, Grant Inst, Sch Geosci, Edinburgh EH9 3JW, Midlothian, Scotland.
6 : Carnegie Inst Sci, Earth & Planets Lab, Washington, DC 20015 USA.
7 : Univ Calif Riverside, Dept Earth & Planetary Sci, Riverside, CA 92521 USA.
8 : Univ Johannesburg, Dept Geol, ZA-2006 Johannesburg, South Africa.
|Source||Science (0036-8075) (Amer Assoc Advancement Science), 2020-10 , Vol. 370 , N. 6515 , P. 446-449|
The role that iron played in the oxygenation of Earth's surface is equivocal. Iron could have consumed molecular oxygen when Fe3+-oxyhydroxides formed in the oceans, or it could have promoted atmospheric oxidation by means of pyrite burial. Through high-precision iron isotopic measurements of Archean-Paleoproterozoic sediments and laboratory grown pyrites, we show that the triple iron isotopic composition of Neoarchean-Paleoproterozoic pyrites requires both extensive marine iron oxidation and sulfide-limited pyritization. Using an isotopic fractionation model informed by these data, we constrain the relative sizes of sedimentary Fe3+- oxyhydroxide and pyrite sinks for Neoarchean marine iron. We show that pyrite burial could have resulted in molecular oxygen export exceeding local Fe2+ oxidation sinks, thereby contributing to early episodes of transient oxygenation of Archean surface environments.
Heard Andy W., Dauphas Nicolas, Guilbaud Romain, Rouxel Olivier, Butler Ian B., Nie Nicole X., Bekker Andrey (2020). Triple iron isotope constraints on the role of ocean iron sinks in early atmospheric oxygenation. Science, 370(6515), 446-449. Publisher's official version : https://doi.org/10.1126/science.aaz8821 , Open Access version : https://archimer.ifremer.fr/doc/00657/76889/