Publication Date:
2014-11-02
Description:
The oxygenation of Earth's surface fundamentally altered global biogeochemical cycles and ultimately paved the way for the rise of metazoans at the end of the Proterozoic. However, current estimates for atmospheric oxygen (O2) levels during the billion years leading up to this time vary widely. On the basis of chromium (Cr) isotope data from a suite of Proterozoic sediments from China, Australia, and North America, interpreted in the context of data from similar depositional environments from Phanerozoic time, we find evidence for inhibited oxidation of Cr at Earth's surface in the mid-Proterozoic (1.8 to 0.8 billion years ago). These data suggest that atmospheric O2 levels were at most 0.1% of present atmospheric levels. Direct evidence for such low O2 concentrations in the Proterozoic helps explain the late emergence and diversification of metazoans.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Planavsky, Noah J -- Reinhard, Christopher T -- Wang, Xiangli -- Thomson, Danielle -- McGoldrick, Peter -- Rainbird, Robert H -- Johnson, Thomas -- Fischer, Woodward W -- Lyons, Timothy W -- New York, N.Y. -- Science. 2014 Oct 31;346(6209):635-8. doi: 10.1126/science.1258410.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department Geology and Geophysics, Yale University, CT, USA. noah.planavsky@yale.edu chris.reinhard@eas.gatech.edu. ; School of Earth and Atmospheric Sciences, Georgia Institute of Technology, GA, USA. noah.planavsky@yale.edu chris.reinhard@eas.gatech.edu. ; Department Geology and Geophysics, Yale University, CT, USA. Department of Geology, University of Illinois, Champaign, IL, USA. ; Department of Earth Science, Carleton University, Ottawa, ON, Canada. ; Centre for Ore Deposit and Exploration Science, University of Tasmania, TAS, Australia. ; Geological Survey of Canada, Ottawa, ON, Canada. ; Department of Geology, University of Illinois, Champaign, IL, USA. ; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA. ; Department of Earth Sciences, University of California, Riverside, CA, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25359975" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Atmosphere/*chemistry
;
*Biological Evolution
;
Chromium Isotopes/chemistry
;
Earth (Planet)
;
Geologic Sediments/chemistry
;
Oxidation-Reduction
;
Oxygen/*analysis
;
Paleontology
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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