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dc.contributor.authorHardistry, Dalton
dc.contributor.authorLu, Zunli
dc.contributor.authorBekker, Andrey
dc.contributor.authorDiamond, Charles
dc.contributor.authorGill, Benjamin
dc.contributor.authorJiang, Ganqing
dc.contributor.authorKah, Linda
dc.contributor.authorKnoll, Andrew
dc.contributor.authorLoyd, Sean
dc.contributor.authorOsburn, Magdalena
dc.contributor.authorPlanavsky, Noah
dc.contributor.authorWang, Chunjiang
dc.contributor.authorZhou, Xiaoli
dc.contributor.authorLyons, Timothy
dc.date.accessioned2019-09-10T18:13:06Z
dc.date.issued2017-04
dc.identifier.citationHardisty, D. S., Z. Lu., A. Bekker, C. W. Diamond, B. C. Gill, G. Jiang, L. C. Kah, A. H. Knoll, S. J. Loyd, M. R. Osburn, N. J. Planavsky, C. Wang, X. Zhou, and T. W. Lyons. 2017. Perspectives on Proterozoic Surface Ocean Redox From Iodine Contents in Ancient and Recent Carbonate. Earth and Planetary Science Letters 463: 159-170.en_US
dc.identifier.issn0012-821Xen_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:41306982*
dc.description.abstractThe Proterozoic Eon hosted the emergence and initial recorded diversification of eukaryotes. Oxygen levels in the shallow marine settings critical to these events were lower than today's, although how much lower is debated. Here, we use concentrations of iodate (the oxidized iodine species) in shallow-marine limestones and dolostones to generate the first comprehensive record of Proterozoic near-surface marine redox conditions. The iodine proxy is sensitive to both local oxygen availability and the relative proximity to anoxic waters. To assess the validity of our approach, Neogene–Quaternary carbonates are used to demonstrate that diagenesis most often decreases and is unlikely to increase carbonate-iodine contents. Despite the potential for diagenetic loss, maximum Proterozoic carbonate iodine levels are elevated relative to those of the Archean, particularly during the Lomagundi and Shuram carbon isotope excursions of the Paleo- and Neoproterozoic, respectively. For the Shuram anomaly, comparisons to Neogene–Quaternary carbonates suggest that diagenesis is not responsible for the observed iodine trends. The baseline low iodine levels in Proterozoic carbonates, relative to the Phanerozoic, are linked to a shallow oxic–anoxic interface. Oxygen concentrations in surface waters would have at least intermittently been above the threshold required to support eukaryotes. However, the diagnostically low iodine data from mid-Proterozoic shallow-water carbonates, relative to those of the bracketing time intervals, are consistent with a dynamic chemocline and anoxic waters that would have episodically mixed upward and laterally into the shallow oceans. This redox instability may have challenged early eukaryotic diversification and expansion, creating an evolutionary landscape unfavorable for the emergence of animals.en_US
dc.description.sponsorshipEarth and Planetary Sciencesen_US
dc.language.isoen_USen_US
dc.publisherElsevieren_US
dc.relation.isversionofdoi: 10.1016/j.epsl.2017.01.032en_US
dash.licenseOAP
dc.titlePerspectives on Proterozoic Surface Ocean Redox From Iodine Contents in Ancient and Recent Carbonateen_US
dc.typeJournal Articleen_US
dc.description.versionAccepted Manuscripten_US
dc.relation.journalEarth and Planetary Science Lettersen_US
dash.depositing.authorKnoll, Andrew
dc.date.available2019-09-10T18:13:06Z
dash.workflow.commentsFAR2017en_US
dc.identifier.doi10.1016/j.epsl.2017.01.032*
dash.contributor.affiliatedLyons, Timothy
dash.contributor.affiliatedKnoll, Andrew


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