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Proc Natl Acad Sci U S A. 2013 Oct 15;110(42):16736-41. doi: 10.1073/pnas.1315570110. Epub 2013 Sep 30.

Oxygen dynamics in the aftermath of the Great Oxidation of Earth's atmosphere.

Author information

1
Nordic Center for Earth Evolution (NordCEE), and Institute of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.

Abstract

The oxygen content of Earth's atmosphere has varied greatly through time, progressing from exceptionally low levels before about 2.3 billion years ago, to much higher levels afterward. In the absence of better information, we usually view the progress in Earth's oxygenation as a series of steps followed by periods of relative stasis. In contrast to this view, and as reported here, a dynamic evolution of Earth's oxygenation is recorded in ancient sediments from the Republic of Gabon from between about 2,150 and 2,080 million years ago. The oldest sediments in this sequence were deposited in well-oxygenated deep waters whereas the youngest were deposited in euxinic waters, which were globally extensive. These fluctuations in oxygenation were likely driven by the comings and goings of the Lomagundi carbon isotope excursion, the longest-lived positive δ(13)C excursion in Earth history, generating a huge oxygen source to the atmosphere. As the Lomagundi event waned, the oxygen source became a net oxygen sink as Lomagundi organic matter became oxidized, driving oxygen to low levels; this state may have persisted for 200 million years.

KEYWORDS:

GOE; Mo isotope; Paleoproterozoic; marine chemistry; trace metal

PMID:
24082125
PMCID:
PMC3801071
DOI:
10.1073/pnas.1315570110
[Indexed for MEDLINE]
Free PMC Article

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