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dc.contributor.authorBoiteau, Rene M.  Concept link
dc.contributor.authorGreaves, Mervyn  Concept link
dc.contributor.authorElderfield, Henry  Concept link
dc.date.accessioned2013-02-14T18:33:50Z
dc.date.available2014-10-22T08:57:22Z
dc.date.issued2012-09-08
dc.identifier.citationPaleoceanography 27 (2012): PA3227en_US
dc.identifier.urihttps://hdl.handle.net/1912/5763
dc.descriptionAuthor Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 27 (2012): PA3227, doi:10.1029/2012PA002335.en_US
dc.description.abstractThe rate of uranium accumulation in oceanic sediments from seawater is controlled by bottom water oxygen concentrations and organic carbon fluxes—two parameters that are linked to deep ocean storage of CO2. To investigate glacial-interglacial changes in what is known as authigenic U, we have developed a rapid method for its determination as a simple addition to a procedure for foraminiferal trace element analysis. Foraminiferal calcite acts as a low U substrate (U/Ca < 15 nmol/mol) upon which authigenic U accumulates in reducing sediments. We measured a downcore record of foraminiferal U/Ca from ODP Site 1090 in the South Atlantic and found that U/Ca ratios increase by 70–320 nmol/mol during glacial intervals. There is a significant correlation between U/Ca records of benthic and planktonic foraminiferal species and between U/Ca and bulk sediment authigenic U. These results indicate that elevated U/Ca ratios are attributable to the accumulation of authigenic U coatings in sediments. Foraminiferal Mn/Ca ratios were lower during the glacial intervals, suggesting that the observed U accumulation on the shells is not directly linked to U incorporation into secondary manganese phases. Thus, foraminiferal U/Ca ratios may provide useful information on past changes in sediment redox conditions.en_US
dc.description.sponsorshipR.B. was funded by the Winston Churchill Foundation, and H.E. was funded by the UK Natural Environment Research Council and the European Research Council.en_US
dc.format.mimetypeapplication/pdf
dc.format.mimetypetext/plain
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2012PA002335
dc.subjectSouth Atlanticen_US
dc.subjectU/Caen_US
dc.subjectAuthigenic uraniumen_US
dc.subjectForaminiferaen_US
dc.subjectGlacial cyclesen_US
dc.subjectRedox paleo-proxyen_US
dc.titleAuthigenic uranium in foraminiferal coatings : a proxy for ocean redox chemistryen_US
dc.typeArticleen_US
dc.description.embargo2013-03-08en_US
dc.identifier.doi10.1029/2012PA002335


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