A Time-Series Geochemical Study of the ca. 2.5 Ga Batatal Formation in Brazil: Sulfur and Carbon Isotopic Insights into Environmental Conditions before the Great Oxidation Event

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dc.contributor.advisorKaufman, Alan Jen_US
dc.contributor.advisorFarquhar, Jamesen_US
dc.contributor.authorZhelezinskaia, Iadvigaen_US
dc.contributor.departmentGeologyen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2013-10-02T05:31:20Z
dc.date.available2013-10-02T05:31:20Z
dc.date.issued2013en_US
dc.description.abstractNeoarchean metasedimentary rocks from the Batatal Formation, Brazil were studied using petrographic, elemental and stable isotopic techniques to provide a better understanding of coupling between the atmosphere-ocean system and biogeochemical cycles prior to the Great Oxidation Event. Multiple sulfur isotope data from both shale and carbonate lithofacies confirms global preservation of mass-independent fractionations, thought to be produced through photochemical reactions in an oxygen-free Neoarchean atmosphere. Isotopic differences between lithofacies within the shallow marine Batatal Formation, and beyond in deeper subtidal environments from correlative successions in Western Australia and South Africa, suggest a strong influence of environmental conditions on the preservation of distinct &Delta<super>33</super>S signatures. To explain the novel isotopic data, it is proposed the Batatal Formation was deposited in a shallow water evaporitic environment, which resulted in higher sulfate concentrations and greater sulfur isotope fractionation associated with the activity of sulfate-reducing bacteria. Higher temperatures associated with such environments may have also promoted carbon dioxide limitation resulting in lesser carbon isotopic fractionation by photoautotrophs.en_US
dc.identifier.urihttp://hdl.handle.net/1903/14447
dc.subject.pqcontrolledGeochemistryen_US
dc.subject.pqcontrolledBiogeochemistryen_US
dc.subject.pqcontrolledPaleoclimate scienceen_US
dc.subject.pquncontrolledArchean sulfur cycleen_US
dc.subject.pquncontrolledCarbon isotopesen_US
dc.subject.pquncontrolledGreat Oxidation Eventen_US
dc.subject.pquncontrolledNeoarcheanen_US
dc.subject.pquncontrolledSulfate-reducing bacteriaen_US
dc.subject.pquncontrolledSulfur isotopesen_US
dc.titleA Time-Series Geochemical Study of the ca. 2.5 Ga Batatal Formation in Brazil: Sulfur and Carbon Isotopic Insights into Environmental Conditions before the Great Oxidation Eventen_US
dc.typeThesisen_US

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