{"NOAAStudyId":"13014","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":"2012-06-17","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-13014.xml","doi":null,"earliestYearBP":20070000,"earliestYearCE":-20068050,"entryId":"noaa-ocean-13014","funding":[{"fundingAgency":"US National Science Foundation","fundingGrant":null}],"investigators":"Feakins, S.J.; Warny, S.; Lee, J.-E.","mostRecentYearBP":15590000,"mostRecentYearCE":-15588050,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/13014","originalSource":null,"publication":[{"abstract":"From 20 to 15 million years (Myr) ago, a period of global warmth \r\nreversed the previous ice growth on Antarctica, leading to the \r\nretreat of the West Antarctic Ice Sheet and the contraction of \r\nthe East Antarctic Ice Sheet. Pollen recovered from the Antarctic \r\nshelf indicates the presence of substantial vegetation on the \r\nmargins of Antarctica 15.7 Myr ago. However, the hydrologic regime \r\nthat supported this vegetation is unclear. Here we combine leaf-wax \r\nhydrogen isotopes and pollen assemblages from Ross Sea sediments\r\nwith model simulations to reconstruct vegetation, precipitation\r\nand temperature in Antarctica during the middle Miocene.\r\nAverage leaf-wax stable hydrogen isotope (dD) values from 20 \r\nto 15.5 Myr ago translate to average dD values of -50 per mil \r\nfor precipitation at the margins of Antarctica, higher than \r\nmodern values. We find that vegetation persisted from 20 to \r\n15.5 Myr ago, with peak expansions 16.4 and 15.7 Myr ago \r\ncoinciding with peak global warmth and vegetation growth. \r\nOur model experiments are consistent with a local moisture \r\nsource in the Southern Ocean. Combining proxy measurements \r\nwith climate simulations, we conclude that summer temperatures\r\nwere about 11°C warmer than today, and that there was a\r\nsubstantial increase in moisture delivery to the Antarctic coast.\r\n\r\n","author":null,"citation":"Feakins, S.J., S. Warny, and J.-E. Lee. 2012.\r\nHydrologic cycling over Antarctica during the Middle Miocene warming. \r\nNature Geoscience, Published online 17 June 2012. \r\ndoi:10.1038/ngeo149","edition":null,"identifier":{"id":"10.1038/ngeo149","type":"doi","url":"http://dx.doi.org/10.1038/ngeo149"},"issue":null,"journal":"Nature Geoscience","pages":null,"pubRank":"1","pubYear":2012,"reportNumber":null,"title":"Hydrologic cycling over Antarctica during the Middle Miocene warming","type":"publication","volume":null}],"reconstruction":"N","scienceKeywords":null,"site":[{"NOAASiteId":"53092","geo":{"geoType":"Feature","geometry":{"coordinates":["-77.7581","165.2769"],"type":"POINT"},"properties":{"easternmostLongitude":"165.2769","maxElevationMeters":"-384","minElevationMeters":"-384","northernmostLatitude":"-77.7581","southernmostLatitude":"-77.7581","westernmostLongitude":"165.2769"}},"locationName":"Ocean>Southern Ocean>Ross Sea","mappable":"Y","paleoData":[{"NOAADataTableId":"22468","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>paleocean>biomarkers"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/feakins2012/feakins2012.txt","linkText":"feakins2012.txt","urlDescription":"Original Data and Full Metadata","variables":[]},{"NOAAKeywords":["earth science>paleoclimate>paleocean>biomarkers"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/feakins2012/feakins2012.xls","linkText":"feakins2012.xls","urlDescription":"Original Data and Full Metadata","variables":[]}],"dataTableName":"AND-2A","dataTableNotes":null,"earliestYear":20070000,"earliestYearBP":20070000,"earliestYearCE":-20068050,"mostRecentYear":15590000,"mostRecentYearBP":15590000,"mostRecentYearCE":-15588050,"species":[],"timeUnit":"cal yr BP"}],"siteName":"AND-2A"}],"studyCode":null,"studyName":"Ross Sea ANDRILL-2A Middle Miocene Biomarker Data","studyNotes":"Paleoprecipitation dD and estimated from leaf wax dD and converted to \ntemperature with modern spatial slope and iGRAM model temporal slope.\nVegetation evidence from pollen assemblages and abundances as well as\nleaf wax abundance. Samples from Antarctic Drilling Project (ANDRILL)\nSite AND2A were used to reconstruct vegetation, precipitation and\ntemperature during the Middle Miocene (~20 to 12 Ma).\n\nANDRILL site AND-2A: 77°45.488’ S, 165°16.613’ E, ~384 m water depth,\ncore to 1139 mbsf, 20-12 Ma\n\nThe model is an idealized gray-radiation aquaplanet moist General\nCirculation Model (GRAM) with the addition of isotopic tracers (iGRAM).\nResults are for experiments where optical depth of the atmosphere to\nlongwave radiation was varied to mimic the effect of changing\ngreenhouse gases and thus to change temperatures in the model.\nThe model was run in T42 resolution (2.8° x 2.8°) and has 30 vertical\nlayers. The simulation was performed for 1400 days with perpetual \nmodern equinox and the results of the last 900 model days are analyzed.\n\n\n","version":"1.0","xmlId":"11056"}