Constraints on Paleoproterozoic atmospheric oxygen levels
Eric J Bellefroid, Ashleigh VS Hood, Paul F Hoffman, Matthew D Thomas, Christopher T Reinhard, Noah J Planavsky
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA | NATL ACAD SCIENCES | Published : 2018
The oxygenation of Earth's surface environment dramatically altered key biological and geochemical cycles and ultimately ushered in the rise of an ecologically diverse biosphere. However, atmospheric oxygen partial pressures (pO2) estimates for large swaths of the Precambrian remain intensely debated. Here we evaluate and explore the use of carbonate cerium (Ce) anomalies (Ce/Ce*) as a quantitative atmospheric pO2 proxy and provide estimates of Proterozoic pO2 using marine carbonates from a unique Precambrian carbonate succession-the Paleoproterozoic Pethei Group. In contrast to most previous work, we measure Ce/Ce* on marine carbonate precipitates that formed in situ across a depth gradient..View full abstract
We thank M. Longley, R. Carpenter, A. Besson, S. Leander, T. Kuhn, K. Rybacki, and D. Cole for their assistance in the field. We are grateful to A. Voldoire and R. Seferian for providing the CNRM data and to J. Deshayes for providing the IPSL model data. E.J.B. acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC). A.v.S.H. acknowledges support from a NASA Astrobiology Postdoctoral Fellowship. This work was supported by the Alternative Earths NASA Astrobiology Institute.