{"NOAAStudyId":"17801","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":"1997-11-30","dataPublisher":"NOAA","dataType":"ICE CORES","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/ice-core","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-icecore-17801.xml","doi":null,"earliestYearBP":16200,"earliestYearCE":-14250,"entryId":"noaa-icecore-17801","funding":[],"investigators":"Lal, D.; Jull, A.J.T.; Burr, G.S.; Donahue, D.J.","mostRecentYearBP":50,"mostRecentYearCE":1900,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/17801","originalSource":null,"publication":[{"abstract":"We present results of measurements of 14C in CO and CO2 phases for selected Greenland Ice Sheet Project 2 firn and ice samples up to a depth of 1838 m (16.6 kyr B.P.). The results show that 14C in ice consists of both in situ-produced cosmogenic 14C, which can be either in the form of CO or CO2, and trapped atmospheric 14CO2. In agreement with our previous work on studies of 14C concentrations in Antarctic firn and ice samples and some GISP2 samples, we found that the cosmogenic in situ-produced 14C (from spallation of oxygen nuclei) is greater than the trapped atmospheric 14C component. Also, we can show the total 14C amounts in ice are consistent with an efficient retention of the in situ variety of 14C in older ice where we expect lower average temperatures at the time of formation. The firn samples appear to have lost much of the 14C, probably during storage. The ice accumulation rates are estimated after due corrections for the CO2 content of trapped air and \"secondary\" 14C production in ice during storage at altitude. These values are in good accord with the recent model estimates of Cutler et al. [1995], except for two samples, at depths 1518.5 m (9740 years B.P.) and 1698.5 m (12,360 years B.P.). In the first case, the in situ 14C concentration is significantly higher than that predicted by either of the models, by a factor of about 2. In the second case, the estimate of Cutler et al. [1995] is a ~50% lower accumulation rate, but the 14C result is consistent with adjacent samples. A possible reason for the first discrepancy may be the decreased atmospheric pressure at that time at the site, as suggested by D. Raynaud et al. (unpublished manuscript, 1995).","author":{"name":"D. Lal, A. J. T. Jull, G. S. Burr, D. J. Donahue"},"citation":"D. Lal, A. J. T. Jull, G. S. Burr, D. J. Donahue. 1997. Measurements of in situ 14C concentrations in Greenland Ice Sheet Project 2 ice covering a 17-kyr time span: Implications to ice flow dynamics. Journal of Geophysical Research: Oceans, 102(C12), 26505-26510. doi: 10.1029/96JC02224","edition":null,"identifier":{"id":"10.1029/96JC02224","type":"doi","url":"http://dx.doi.org/10.1029/96JC02224"},"issue":"C12","journal":"Journal of Geophysical Research: Oceans","pages":"26505-26510","pubRank":"1","pubYear":1997,"reportNumber":null,"title":"Measurements of in situ 14C concentrations in Greenland Ice Sheet Project 2 ice covering a 17-kyr time span: Implications to ice flow dynamics","type":"publication","volume":"102"}],"reconstruction":"N","scienceKeywords":null,"site":[{"NOAASiteId":"19978","geo":{"geoType":"Feature","geometry":{"coordinates":["72.6","-38.5"],"type":"POINT"},"properties":{"easternmostLongitude":"-38.5","maxElevationMeters":"3200","minElevationMeters":"3200","northernmostLatitude":"72.6","southernmostLatitude":"72.6","westernmostLongitude":"-38.5"}},"locationName":"Continent>North America>Greenland","mappable":"Y","paleoData":[{"NOAADataTableId":"28121","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>ice core>radiogenic isotopes"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/cosmoiso/c14a.txt","linkText":"GISP2 14-C Table 1","urlDescription":"Data File","variables":[{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth>depth at sample end"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth>depth at sample start"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar year before present","cvWhat":"age variable>age"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"hydrologic material>bulk ice","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"kilogram","cvWhat":"physical property>weight"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"hydrologic material>bulk ice","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"cubic centimeter per liter","cvWhat":"physical property>porosity>air content"},{"cvAdditionalInfo":"atom per gram","cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>inorganic compound>carbon dioxide","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"count per gram","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":"atom per gram","cvDataType":"ICE CORES","cvDetail":null,"cvError":"unspecified margin of error","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>inorganic compound>carbon dioxide","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"count per gram","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":"atom per gram","cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>inorganic compound>carbon monoxide","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"count per gram","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":"atom per gram","cvDataType":"ICE CORES","cvDetail":null,"cvError":"unspecified margin of error","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>inorganic compound>carbon monoxide","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"count per gram","cvWhat":"chemical composition>isotope>single isotope concentration>14C"}]},{"NOAAKeywords":["earth science>paleoclimate>ice core>radiogenic isotopes"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/cosmoiso/c14b.txt","linkText":"GISP2 14-C Table 2","urlDescription":"Data File","variables":[{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar year before present","cvWhat":"age variable>age"},{"cvAdditionalInfo":"Total: Decay-corrected 14C; 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