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dc.contributor.authorJohnston, David T
dc.contributor.authorPoulton, S.W.
dc.contributor.authorTosca, N.J.
dc.contributor.authorO'Brien, T.
dc.contributor.authorHalverson, G.P.
dc.contributor.authorSchrag, Daniel P.
dc.contributor.authorMacdonald, Francis Alexander
dc.date.accessioned2017-07-11T18:43:12Z
dc.date.issued2013
dc.identifier.citationJohnston, D.T., S.W. Poulton, N.J. Tosca, T. O’Brien, G.P. Halverson, D.P. Schrag, and F.A. Macdonald. 2013. “Searching for an Oxygenation Event in the Fossiliferous Ediacaran of Northwestern Canada.” Chemical Geology 362 (December): 273–286. doi:10.1016/j.chemgeo.2013.08.046.en_US
dc.identifier.issn0009-2541en_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:33370039
dc.description.abstractLate Neoproterozoic (Ediacaran) strata from northwestern Canada provide a thick and rich sedimentological record, preserving intercalated carbonates and shale extending from the ~ 635 million year old Marinoan glacial deposits up through the ~ 541 million year old Precambrian–Cambrian boundary. This region also holds one of the classic localities for the study of early animal life, with the ensuing suggestion that this temporal interval captures a gross change in the O2 content of the Earth's atmosphere. To test this hypothesis and bring records of northwestern Canada into line with other Ediacaran, fossil-bearing basins, we provide a detailed geochemical reconstruction from the Wernecke Mountains of the Yukon. Where possible, we also extend these records to the Ogilvie Mountains to the west and previously published data from the Mackenzie Mountains to the east. Our work in the Wernecke Mountains is set against a composite δ13C record for carbonate that preserves three distinct Ediacaran isotope excursions, the lowermost of which (preserved in the Gametrail Formation) is a putative Shuram excursion equivalent. What emerges from a multi-proxy (Fe speciation, sulfur isotopes, major and trace element analyses) reconstruction is a picture of a persistently anoxic and ferruginous Ediacaran ocean. Notably absent is geochemical evidence for a prominent oxygenation event, an expectation given the appearance of animals and large swings in δ13C. The new insight gained through these data challenges the idea of an Ediacaran jump in atmospheric oxygen, which in turn muddles the link between animal evolution and local geochemical environments.en_US
dc.description.sponsorshipEarth and Planetary Sciencesen_US
dc.language.isoen_USen_US
dc.publisherElsevier BVen_US
dc.relation.isversionofdoi:10.1016/j.chemgeo.2013.08.046en_US
dc.relation.hasversionhttp://projects.iq.harvard.edu/files/fmacdonald/files/2013_searching_for_an_oxygenation_event.pdfen_US
dash.licenseMETA_ONLY
dc.subjectOxygenen_US
dc.subjectEdiacaranen_US
dc.subjectAnimalsen_US
dc.subjectBiogeochemistryen_US
dc.subjectShuramen_US
dc.titleSearching for an oxygenation event in the fossiliferous Ediacaran of northwestern Canadaen_US
dc.typeJournal Articleen_US
dc.description.versionProofen_US
dc.relation.journalChemical Geologyen_US
dash.depositing.authorMacdonald, Francis Alexander
dash.embargo.until10000-01-01
dc.identifier.doi10.1016/j.chemgeo.2013.08.046*
workflow.legacycommentsFAR 2014 Ask Macdonald for manuscript (Johnston said he couldn't produce manuscript and requested dark deposit) Macdonald emailed 2016-05-04 AD Macdonald emailed 2017-02-24 MM meta.darken_US
dash.authorsorderedfalse
dash.contributor.affiliatedJohnston, David
dash.contributor.affiliatedSchrag, Daniel
dash.contributor.affiliatedMacdonald, Francis


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