{"NOAAStudyId":"20145","contactInfo":{"address":"325 Broadway, E/NE31","city":"Boulder","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.","country":"USA","dataCenterUrl":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data","email":"paleo@noaa.gov","fax":"303-497-6513","longName":"National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce ","phone":"303-497-6280","postalCode":"80305-3328","shortName":"DOC/NOAA/NESDIS/NCEI","state":"CO","type":"CONTACT INFORMATION"},"contributionDate":"2016-08-23","dataPublisher":"NOAA","dataType":"PALEOCEANOGRAPHY","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/paleoceanography","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-ocean-20145.xml","doi":null,"earliestYearBP":5249000,"earliestYearCE":-5247050,"entryId":"noaa-ocean-20145","funding":[{"fundingAgency":"US National Science Foundation","fundingGrant":"OCE-1203892"}],"investigators":"Liddy, H.M.; Feakins, S.J.; Tierney, J.E.","mostRecentYearBP":2001000,"mostRecentYearCE":-1999050,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/20145","originalSource":null,"publication":[{"abstract":"Terrestrial records suggest that Northeast Africa experienced drying during the Pliocene; however, these records are often incomplete in time and space, and questions about this shift in climate remain. Here, we use marine sediments from Deep Sea Drilling Project (DSDP) Site 231 in the Gulf of Aden to generate a multi-proxy organic geochemical record of northeast African climate spanning 5.3-2 Ma. This new record provides a regional perspective on climate and serves as context for the fossil record of early hominin evolution. We measured leaf wax carbon (d13Cwax) and hydrogen (dDwax) isotopic composition and TEX86 (tetraether index of 86 carbons) to investigate past changes in vegetation, aridity, and ocean temperature, respectively. In the earliest Pliocene, we infer warm subsurface ocean temperatures from TEX86, semi-arid conditions on land and extensive C4 grasslands based on dDwax, d13Cwax and previously published pollen. After 5 Ma, ocean temperatures gradually cooled, and at 4.3 Ma there was a transition to arid conditions on land based on dDwax and pollen. Grasslands yielded to a mid Pliocene landscape of dry shrublands. This drying appears to be an atmospheric response to cooling ocean temperatures, which may reflect changes in tropical ocean circulation, the intensification of Indian Monsoon winds or perhaps other changes associated with Pliocene cooling. ","author":{"name":"Hannah M. Liddy, Sarah J. Feakins, Jessica E. Tierney"},"citation":"Hannah M. Liddy, Sarah J. Feakins, Jessica E. Tierney. 2016. Cooling and drying in northeast Africa across the Pliocene. Earth and Planetary Science Letters, 449, 430-438. doi: 10.1016/j.epsl.2016.05.005","edition":null,"identifier":{"id":"10.1016/j.epsl.2016.05.005","type":"doi","url":"http://dx.doi.org/10.1016/j.epsl.2016.05.005"},"issue":null,"journal":"Earth and Planetary Science Letters","pages":"430-438","pubRank":"1","pubYear":2016,"reportNumber":null,"title":"Cooling and drying in northeast Africa across the Pliocene","type":"publication","volume":"449"}],"reconstruction":"Y","scienceKeywords":null,"site":[{"NOAASiteId":"54324","geo":{"geoType":"Feature","geometry":{"coordinates":["11.89","48.25"],"type":"POINT"},"properties":{"easternmostLongitude":"48.25","maxElevationMeters":"-2152","minElevationMeters":"-2152","northernmostLatitude":"11.89","southernmostLatitude":"11.89","westernmostLongitude":"48.25"}},"locationName":"Ocean>Indian Ocean>Arabian Sea","mappable":"Y","paleoData":[{"NOAADataTableId":"30808","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>paleocean>carbon isotopes"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/liddy2016/liddy2016d13c.txt","linkText":"Plant wax carbon isotope data from DSDP Site 231","urlDescription":"Data File","variables":[{"cvAdditionalInfo":"* indicates n-C30 data from Feakins et al. 2005 and Feakins et al. 2013","cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":null,"cvFormat":"Character","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":null,"cvWhat":"sampling metadata>notes"},{"cvAdditionalInfo":null,"cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":null,"cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"million years ago","cvWhat":"age variable>age"},{"cvAdditionalInfo":"leaf wax interpretation","cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>organooxygen compound>fatty acid>n-alkanoic acid>C28 n-alkanoic acid","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil VPDB","cvWhat":"chemical composition>isotope>isotope ratio>delta 13C"},{"cvAdditionalInfo":"leaf wax interpretation","cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>organooxygen compound>fatty acid>n-alkanoic acid>C30 n-alkanoic acid","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil VPDB","cvWhat":"chemical composition>isotope>isotope ratio>delta 13C"},{"cvAdditionalInfo":"standard deviation of replicates; leaf wax interpretation","cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":"one standard deviation","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>organooxygen compound>fatty acid>n-alkanoic acid>C30 n-alkanoic acid","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil","cvWhat":"chemical composition>isotope>isotope ratio>delta 13C"},{"cvAdditionalInfo":"leaf wax interpretation","cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>organooxygen compound>fatty acid>n-alkanoic acid>C32 n-alkanoic acid","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil VPDB","cvWhat":"chemical composition>isotope>isotope ratio>delta 13C"},{"cvAdditionalInfo":"standard deviation of replicates; leaf wax interpretation","cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":"one standard deviation","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>organooxygen compound>fatty acid>n-alkanoic acid>C32 n-alkanoic acid","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil","cvWhat":"chemical composition>isotope>isotope ratio>delta 13C"},{"cvAdditionalInfo":"standard deviation of replicates; leaf wax interpretation","cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":"one standard deviation","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>organooxygen compound>fatty acid>n-alkanoic acid>C28 n-alkanoic acid","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil","cvWhat":"chemical composition>isotope>isotope ratio>delta 13C"}]}],"dataTableName":"Liddy2016d13c","dataTableNotes":null,"earliestYear":5249000,"earliestYearBP":5249000,"earliestYearCE":-5247050,"mostRecentYear":2001000,"mostRecentYearBP":2001000,"mostRecentYearCE":-1999050,"species":[],"timeUnit":"cal yr BP"},{"NOAADataTableId":"30809","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>paleocean>biomarkers"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/liddy2016/liddy2016d2h.txt","linkText":"Plant wax hydrogen Isotope data from DSDP Site 231","urlDescription":"Data File","variables":[{"cvAdditionalInfo":"standard deviation of replicates; leaf wax interpretation","cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":"one standard deviation","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>organooxygen compound>fatty acid>n-alkanoic acid>C28 n-alkanoic acid","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil","cvWhat":"chemical composition>isotope>isotope ratio>delta 2H"},{"cvAdditionalInfo":null,"cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":null,"cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"million years ago","cvWhat":"age variable>age"},{"cvAdditionalInfo":"leaf wax interpretation","cvDataType":"PALEOCEANOGRAPHY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>organooxygen compound>fatty acid>n-alkanoic acid>C28 n-alkanoic acid","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil VSMOW","cvWhat":"chemical composition>isotope>isotope ratio>delta 2H"}]}],"dataTableName":"Liddy2016d2H","dataTableNotes":null,"earliestYear":5239000,"earliestYearBP":5239000,"earliestYearCE":-5237050,"mostRecentYear":2159000,"mostRecentYearBP":2159000,"mostRecentYearCE":-2157050,"species":[],"timeUnit":"cal yr BP"},{"NOAADataTableId":"30810","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>paleocean>biomarkers"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/liddy2016/liddy2016tex86.txt","linkText":"GDGT results (TEX86, BIT, SST) from DSDP Site 231","urlDescription":"Data File","variables":[{"cvAdditionalInfo":"Mean calibrated subsurface ocean temperature from TEX86 using BAYSPAR subsurface calibration (Tierney and Tingley 2015)","cvDataType":"CLIMATE RECONSTRUCTIONS|PALEOCEANOGRAPHY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"reconstruction material>organic compound index>glycerol dialkyl glycerol tetraether index","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"degree Celsius","cvWhat":"earth system variable>temperature variable>temperature>sea water temperature"},{"cvAdditionalInfo":"using BAYSPAR subsurface calibration (Tierney and Tingley 2015); 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During the same interval, Gulf of Aden TEX86 values reflects subsurface ocean temperatures, and BIT index values are used to assess the GDGT contribution from soils. ","version":"1.0","xmlId":"17959"}