Publication Date:
2005-02-19
Description:
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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rouxel, Olivier J -- Bekker, Andrey -- Edwards, Katrina J -- New York, N.Y. -- Science. 2005 Feb 18;307(5712):1088-91.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Marine Chemistry and Geochemistry Department, Geomicrobiology Group, Woods Hole Oceanographic Institution, Mail Stop 8, Woods Hole, MA 02543, USA. orouxel@whoi.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15718467" target="_blank"〉PubMed〈/a〉
Keywords:
*Atmosphere
;
Chemical Precipitation
;
Ferric Compounds/analysis
;
Geologic Sediments/*chemistry
;
Iron/*analysis
;
Iron Isotopes/*analysis
;
Oceans and Seas
;
Oxidation-Reduction
;
Oxygen
;
*Seawater
;
Sulfides/*analysis
;
Time
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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