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dc.contributor.authorPlanavsky, Noah J.en_NZ
dc.contributor.authorReinhard, Christopher T.en_NZ
dc.contributor.authorIsson, Terry T.en_NZ
dc.contributor.authorOzaki, Kazumien_NZ
dc.contributor.authorCrockford, Peter W.en_NZ
dc.coverage.spatialUnited Statesen_NZ
dc.date.accessioned2020-08-25T02:25:21Z
dc.date.available2020-08-25T02:25:21Z
dc.date.issued2020en_NZ
dc.identifier.citationPlanavsky, N. J., Reinhard, C. T., Isson, T. T., Ozaki, K., & Crockford, P. W. (2020). Large mass-independent oxygen isotope fractionations in mid-Proterozoic sediments: Evidence for a low-oxygen atmosphere? Astrobiology, 20(5), 628–636. https://doi.org/10.1089/ast.2019.2060en
dc.identifier.urihttps://hdl.handle.net/10289/13753
dc.description.abstractEarth's ocean-atmosphere system has undergone a dramatic but protracted increase in oxygen (O₂) abundance. This environmental transition ultimately paved the way for the rise of multicellular life and provides a blueprint for how a biosphere can transform a planetary surface. However, estimates of atmospheric oxygen levels for large intervals of Earth's history still vary by orders of magnitude-foremost for Earth's middle history. Historically, estimates of mid-Proterozoic (1.9-0.8 Ga) atmospheric oxygen levels are inferred based on the kinetics of reactions occurring in soils or in the oceans, rather than being directly tracked by atmospheric signatures. Rare oxygen isotope systematics-based on quantifying the rare oxygen isotope ¹⁷O in addition to the conventionally determined ¹⁶O and ¹⁸O-provide a means to track atmospheric isotopic signatures and thus potentially provide more direct estimates of atmospheric oxygen levels through time. Oxygen isotope signatures that deviate strongly from the expected mass-dependent relationship between ¹⁶O, ¹⁷O, and ¹⁸O develop during ozone formation, and these "mass-independent" signals can be transferred to the rock record during oxidation reactions in surface environments that involve atmospheric O₂. The magnitude of these signals is dependent upon 𝘱O₂, 𝘱CO₂, and the overall extent of biospheric productivity. Here, we use a stochastic approach to invert the mid-Proterozoic Δ¹⁷O record for a new estimate of atmospheric 𝘱O₂, leveraging explicit coupling of 𝘱O₂ and biospheric productivity in a biogeochemical Earth system model to refine the range of atmospheric 𝘱O₂ values that is consistent with a given observed Δ¹⁷O. Using this approach, we find new evidence that atmospheric oxygen levels were less than ∼1% of the present atmospheric level (PAL) for at least some intervals of the Proterozoic Eon.en_NZ
dc.format.mimetypeapplication/pdf
dc.language.isoenen_NZ
dc.publisherMary Ann LIebert
dc.rightsThis is an author's accepted version of an article published in Astrobiology. © 2020 Mary Ann LIebert, Inc. Final publication is available from Mary Ann Liebert, Inc., publishers http://dx.doi.org/10.1089/ast.2019.2060
dc.subjectAtmospheric oxygenationen_NZ
dc.subjectPrecambrianen_NZ
dc.subjectProterozoicen_NZ
dc.subjectTriple oxygenen_NZ
dc.titleLarge mass-independent oxygen isotope fractionations in mid-Proterozoic sediments: Evidence for a low-oxygen atmosphere?en_NZ
dc.typeJournal Article
dc.identifier.doi10.1089/ast.2019.2060en_NZ
dc.relation.isPartOfAstrobiologyen_NZ
pubs.begin-page628
pubs.elements-id255940
pubs.end-page636
pubs.issue5en_NZ
pubs.publication-statusPublisheden_NZ
pubs.volume20en_NZ
dc.identifier.eissn1557-8070en_NZ


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