{"xmlId":"70591","NOAAStudyId":"28691","studyName":"Authigenic uranium concentrations in the Deep South Atlantic during the past 470 thousand years","doi":"https://doi.org/10.25921/5w7t-zj35","uuid":"5501719d-9ba1-4251-95a6-d62642f7f227","dataPublisher":"NOAA","contactInfo":{"type":"CONTACT INFORMATION","shortName":"DOC/NOAA/NESDIS/NCEI","longName":"National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce ","address":"325 Broadway, E/NE31","city":"Boulder","state":"CO","postalCode":"80305-3328","country":"USA","dataCenterUrl":"https://www.ncei.noaa.gov/products/paleoclimatology","email":"paleo@noaa.gov","phone":"828-271-4800","fax":null,"constraints":"Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site."},"dataType":"PALEOCEANOGRAPHY","investigators":"Glasscock, S.K.; Hayes, C.T.; Redmond, N.; Rohde, E.","investigatorDetails":[{"firstName":"Samuel","lastName":"Glasscock","initials":"S.K.","orcId":null},{"firstName":"Christopher","lastName":"Hayes","initials":"C.T.","orcId":"0000-0002-5636-2989"},{"firstName":"Neil","lastName":"Redmond","initials":"N.","orcId":null},{"firstName":"Evan","lastName":"Rohde","initials":"E.","orcId":null}],"version":"1.0","funding":[{"fundingAgency":"US National Science Foundation","fundingGrant":"1658445"}],"studyNotes":null,"onlineResourceLink":"https://www.ncei.noaa.gov/access/paleo-search/study/28691","difMetadataLink":"https://www.ncei.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-ocean-28691.xml","isoMetadataLink":"https://www.ncei.noaa.gov/pub/data/metadata/published/paleo/iso/xml/noaa-ocean-28691.xml","originalSource":null,"dataTypeInformation":"https://www.ncei.noaa.gov/products/paleoclimatology/paleoceanography","studyCode":null,"scienceKeywords":null,"reconstruction":"N","contributionDate":"2020-01-14","entryId":"noaa-ocean-28691","earliestYearBP":466600,"mostRecentYearBP":1217,"earliestYearCE":-464650,"mostRecentYearCE":733,"publication":[{"author":{"name":"Glasscock, S.K., C.T. Hayes, N. Redmond, E. Rohde"},"pubYear":2020,"title":"Changes in Antarctic Bottom Water Formation During Interglacial Periods","journal":"Paleoceanography and Paleoclimatology","volume":"35","edition":null,"issue":null,"pages":null,"reportNumber":"e2020PA003867","citation":"Glasscock, S.K., C.T. Hayes, N. Redmond, E. Rohde. 2020. Changes in Antarctic Bottom Water Formation During Interglacial Periods. Paleoceanography and Paleoclimatology, 35, e2020PA003867. doi: 10.1029/2020PA003867","type":"publication","identifier":{"type":"doi","id":"10.1029/2020PA003867","url":"http://dx.doi.org/10.1029/2020PA003867"},"abstract":"In the modern Southern Ocean and during the last interglacial period, Marine Isotope Stage 5, there are observations that point to reduced Antarctic Bottom Water (AABW) formation. These reductions are believed to be driven by an increase in the strength of the Southern Ocean density stratification due to surface water freshening. Any reduction in AABW formation has important implications for global climate as AABW plays a vital role in the cycling of carbon in the world's ocean. The primary question this study seeks to answer is do these AABW reductions occur during any of the other interglacials of the past 500 thousand years? To study AABW changes in the paleoceanographic record we look at changes in the redox record. Newly formed AABW is oxygen-rich, so any reduction should lead to a decrease in oxygen concentrations in the deep Southern Ocean. The trace element uranium is useful for studying these redox changes as it is enriched in marine sediments under low-oxygen conditions. When accounting for other factors, such as paleoproductivity, that can also decrease the oxygen concentrations in sedimentary porewater, it is possible to identify changes in AABW using authigenic uranium. The survey conducted by this study found a possible AABW reduction during late Marine Isotope Stage 11 (~395 ka). However, this reduction does not appear to be triggered by a decrease in surface water density. Instead, a change in the strength or position of the southern hemisphere westerly winds is hypothesized to be the driving mechanism behind this reduction.","pubRank":"1"}],"site":[{"NOAASiteId":"19271","siteName":"ODP 1094","siteCode":null,"mappable":"Y","locationName":"Ocean>Atlantic Ocean>South Atlantic Ocean","geo":{"geoType":"Feature","geometry":{"type":"POINT","coordinates":["-53.18035","5.130333"]},"properties":{"southernmostLatitude":"-53.18035","northernmostLatitude":"-53.18035","westernmostLongitude":"5.130333","easternmostLongitude":"5.130333","minElevationMeters":"-2807","maxElevationMeters":"-2807"}},"paleoData":[{"dataTableName":"ODP1094 Uranium Glasscock2020","NOAADataTableId":"41058","earliestYear":466600,"mostRecentYear":1217,"timeUnit":"cal yr BP","earliestYearBP":466600,"mostRecentYearBP":1217,"earliestYearCE":-464650,"mostRecentYearCE":733,"coreLengthMeters":75,"dataTableNotes":null,"species":[],"dataFile":[{"fileUrl":"https://www.ncei.noaa.gov/pub/data/paleo/contributions_by_author/glasscock2020/glasscock2020-uranium.txt","urlDescription":"NOAA Template File","linkText":"ODP 1094 Uranium Data","variables":[{"cvDataType":"PALEOCEANOGRAPHY","cvWhat":"depth variable>depth","cvMaterial":null,"cvError":null,"cvUnit":"length unit>meter","cvSeasonality":null,"cvDetail":null,"cvMethod":null,"cvAdditionalInfo":null,"cvFormat":"Numeric","cvShortName":"mcd_top"},{"cvDataType":"PALEOCEANOGRAPHY","cvWhat":"age variable>age","cvMaterial":null,"cvError":null,"cvUnit":"time unit>age unit>calendar kiloyear before present","cvSeasonality":null,"cvDetail":null,"cvMethod":null,"cvAdditionalInfo":null,"cvFormat":"Numeric","cvShortName":"age_kaBP"},{"cvDataType":"PALEOCEANOGRAPHY","cvWhat":"chemical composition>element or single-element molecule>uranium","cvMaterial":"geological material>bulk geological material>sediment>dry sediment","cvError":null,"cvUnit":"concentration unit>parts per notation unit>parts per million","cvSeasonality":null,"cvDetail":null,"cvMethod":"laboratory method>elemental analysis","cvAdditionalInfo":null,"cvFormat":"Numeric","cvShortName":"U_238_ppm"},{"cvDataType":"PALEOCEANOGRAPHY","cvWhat":"chemical composition>element or single-element molecule>thorium","cvMaterial":"geological material>bulk geological material>sediment>dry sediment","cvError":null,"cvUnit":"concentration unit>parts per notation unit>parts per million","cvSeasonality":null,"cvDetail":null,"cvMethod":"laboratory method>elemental analysis","cvAdditionalInfo":null,"cvFormat":"Numeric","cvShortName":"Th_232_ppm"},{"cvDataType":"PALEOCEANOGRAPHY","cvWhat":"chemical composition>element or single-element molecule>uranium","cvMaterial":"geological material>bulk geological material>sediment>dry sediment","cvError":null,"cvUnit":"concentration unit>parts per notation unit>parts per million","cvSeasonality":null,"cvDetail":null,"cvMethod":null,"cvAdditionalInfo":"Authigenic uranium is calculated by subtracting from the total measured uranium an estimate of the lithogenic uranium based on measured thorium-232 where available","cvFormat":"Numeric","cvShortName":"aU_ppm"}],"NOAAKeywords":["earth science>paleoclimate>paleocean>geochemistry"]}]}]}],"reference":{"pastThesaurusSkos":"https://www.ncei.noaa.gov/access/paleo-search/skos/past-thesaurus.rdf","pastThesaurusExplorer":"https://www.ncei.noaa.gov/access/paleo-search/cvterms","gcmdKeywordThesaurus":"https://earthdata.nasa.gov/earth-observation-data/find-data/idn/gcmd-keywords"},"dataLicenseDescription":null,"dataLicenseUrl":null}