Iron isotope constraints on the Archean and Paleoproterozoic ocean redox state

Type Article
Date 2005-02
Language English
Author(s) Rouxel OlivierORCID, Bekker A, Edwards Kj
Affiliation(s) Woods Hole Oceanog Inst, Marine Chem & Geochem Dept, Geomicrobiol Grp, Woods Hole, MA 02543 USA.
Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA.
Source Science (0036-8075) (Amer Assoc Advancement Science), 2005-02 , Vol. 307 , N. 5712 , P. 1088-1091
DOI 10.1126/science.1105692
WOS© Times Cited 310
Abstract The response of the ocean redox state to the rise of atmospheric oxygen about 2.3 billion years ago (Ga) is a matter of controversy. Here we provide iron isotope evidence that the change in the ocean iron cycle occurred at the same time as the change in the atmospheric redox state. Variable and negative iron isotope values in pyrites older than about 2.3 Ga suggest that an iron-rich global ocean was strongly affected by the deposition of iron oxides. Between 2.3 and 1.8 Ga, positive iron isotope values of pyrite likely reflect an increase in the precipitation of iron sulfides relative to iron oxides in a redox stratified ocean.
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