Low Mid-Proterozoic atmospheric oxygen levels and the delayed rise of animals
Abstract
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.
Additional Information
Copyright © 2014, American Association for the Advancement of Science. Received for publication 7 July 2014. Accepted for publication 30 September 2014. N.J.P., C.T.R., X.W., T.J, and T.W.L. acknowledge funding from NASA Exobiology Program. N.J.P., C.T.R., and T.W.L. acknowledge funding from the NSF-ELT program. C.T.R. acknowledges an O.K. Earl fellowship from the California Institute of Technology. R.H.R. and D.T. acknowledge funding from a National Science and Engineering Research Council of Canada Discovery Grant and by Natural Resources Canada's GEM Program. P.McG. acknowledges funding through the Australian Research Council's Centres of Excellence Program and thanks S. Gilbert for expert help with the LA-ICPMS work. We are indebted to A. Bekker, B. Maynard, A. Hofmann, K. Konhauser, J. Owens, C. Li, and G. Love for discussion and samples. Full data tables are in the supplementary materials.Attached Files
Supplemental Material - DatabaseS1.xls
Supplemental Material - DatabaseS2.xls
Supplemental Material - Planavsky.SM.pdf
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Additional details
- Eprint ID
- 50325
- DOI
- 10.1126/science.1258410
- Resolver ID
- CaltechAUTHORS:20141009-185334240
- NASA
- NSF
- O.K. Earl Postdoctoral Fellowship, Caltech
- National Science and Engineering Research Council of Canada (NSERC)
- Natural Resources Canada
- Australian Research Council
- Created
-
2014-11-12Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field