{"NOAAStudyId":"12255","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":"2011-10-16","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-12255.xml","doi":null,"earliestYearBP":11739,"earliestYearCE":-9789,"entryId":"noaa-icecore-12255","funding":[{"fundingAgency":"US National Science Foundation","fundingGrant":"OPP0221470, OPP0221410"},{"fundingAgency":"Packard Fellowship","fundingGrant":null},{"fundingAgency":"American Chemical Society","fundingGrant":null},{"fundingAgency":"New Zealand Foundation  of Science and Technology","fundingGrant":"C01X0703"},{"fundingAgency":"Australian Climate Change Science Program","fundingGrant":null}],"investigators":"Petrenko, V.V.; Smith, A.M.; Brook, E.J.; Lowe, D.; Riedel, K.; Brailsford, G.; Hua, Q.; Schaefer, H.; Reeh, N.; Weiss, R.F.; Etheridge, D.M.; Severinghaus, J.","mostRecentYearBP":11293,"mostRecentYearCE":-9343,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/12255","originalSource":null,"publication":[{"abstract":"The cause of a large increase of atmospheric methane concentration \r\nduring the Younger Dryas-Preboreal abrupt climatic transition \r\n(~11,600 years ago) has been the subject of much debate. \r\nThe carbon-14 (14C) content of methane (14CH4) should distinguish \r\nbetween wetland and clathrate contributions to this increase. \r\nWe present measurements of 14CH4 in glacial ice, targeting this \r\ntransition, performed by using ice samples obtained from an \r\nablation site in west Greenland.  Measured 14CH4 values were \r\nhigher than predicted under any scenario. Sample 14CH4 appears \r\nto be elevated by direct cosmogenic 14C production in ice. \r\n14C of CO was measured to better understand this process \r\nand correct the sample 14CH4. Corrected results suggest that \r\nwetland sources were likely responsible for the majority \r\nof the Younger Dryas–Preboreal CH4 rise.\r\n","author":null,"citation":"Petrenko, V.V., A.M. Smith, E.J. Brook, D. Lowe, K. Riedel, \r\nG. Brailsford, Q. Hua, H. Schaefer, N. Reeh, R.F. Weiss, \r\nD. Etheridge, and J.P. Severinghaus. 2009. \r\n14CH4 Measurements in Greenland Ice: Investigating Last Glacial \r\nTermination CH4 Sources. \r\nScience, Vol. 324, pp. 506-508, 24 April 2009.\r\n10.1126/science.1168909\r\n","edition":null,"identifier":{"id":"10.1126/science.1168909","type":"doi","url":"http://dx.doi.org/10.1126/science.1168909"},"issue":null,"journal":"Science","pages":null,"pubRank":"1","pubYear":2009,"reportNumber":null,"title":"14CH4 Measurements in Greenland Ice: Investigating Last Glacial  Termination CH4 Sources","type":"publication","volume":null}],"reconstruction":"N","scienceKeywords":["Younger Dryas"],"site":[{"NOAASiteId":"20012","geo":{"geoType":"Feature","geometry":{"coordinates":["69.48","-50.8"],"type":"POINT"},"properties":{"easternmostLongitude":"-50.8","maxElevationMeters":null,"minElevationMeters":null,"northernmostLatitude":"69.48","southernmostLatitude":"69.48","westernmostLongitude":"-50.8"}},"locationName":"Continent>North America>Greenland","mappable":"Y","paleoData":[{"NOAADataTableId":"20577","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>ice core>carbon isotopes"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/pakitsoq2009-14ch4.txt","linkText":"pakitsoq2009-14ch4.txt","urlDescription":"Data","variables":[{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Character","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":null,"cvWhat":"sampling metadata>sample identification"},{"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>gas age"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":"range upper bound","cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar year before present","cvWhat":"age variable>age>gas age"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":"range lower bound","cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar year before present","cvWhat":"age variable>age>gas age"},{"cvAdditionalInfo":"percent modern","cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>hydrocarbon>alkane>n-alkane>methane","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":"one standard deviation","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>hydrocarbon>alkane>n-alkane>methane","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"cvDataType":"CLIMATE FORCING|ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"atmospheric material>bulk atmosphere","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"parts per billion","cvWhat":"chemical composition>compound>organic compound>hydrocarbon>alkane>n-alkane>methane"},{"cvAdditionalInfo":null,"cvDataType":"CLIMATE FORCING|ICE CORES","cvDetail":null,"cvError":"one standard deviation","cvFormat":"Numeric","cvMaterial":"atmospheric material>bulk atmosphere","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"parts per billion","cvWhat":"chemical composition>compound>organic compound>hydrocarbon>alkane>n-alkane>methane"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":"corrected","cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>hydrocarbon>alkane>n-alkane>methane","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":"corrected","cvError":"one standard deviation","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>organic compound>hydrocarbon>alkane>n-alkane>methane","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"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":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":"one standard deviation","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>inorganic compound>carbon monoxide","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"cvDataType":"CLIMATE FORCING|ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"atmospheric material>bulk atmosphere","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"parts per billion","cvWhat":"chemical composition>compound>inorganic compound>carbon monoxide"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":"corrected","cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>inorganic compound>carbon monoxide","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":"corrected","cvError":"one standard deviation","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>inorganic compound>carbon monoxide","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>inorganic compound>carbon monoxide","cvMethod":"numerical simulation","cvSeasonality":null,"cvShortName":null,"cvUnit":"molecule per gram","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"cvDataType":"CLIMATE FORCING|ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"atmospheric material>bulk atmosphere","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"parts per million","cvWhat":"chemical composition>compound>inorganic compound>carbon dioxide"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":"corrected","cvError":null,"cvFormat":"Numeric","cvMaterial":"chemical composition>compound>inorganic compound>carbon dioxide","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":"corrected","cvError":"one standard deviation","cvFormat":"Numeric","cvMaterial":"chemical composition>compound>inorganic compound>carbon dioxide","cvMethod":"accelerator mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"},{"cvAdditionalInfo":null,"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":"percent","cvWhat":"chemical composition>isotope>single isotope concentration>14C"}]},{"NOAAKeywords":["earth science>paleoclimate>ice core>carbon isotopes"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/pakitsoq2009-14ch4.xls","linkText":"pakitsoq2009-14ch4.xls","urlDescription":"Data","variables":[]}],"dataTableName":"Pakitsoq09","dataTableNotes":null,"earliestYear":11739,"earliestYearBP":11739,"earliestYearCE":-9789,"mostRecentYear":11293,"mostRecentYearBP":11293,"mostRecentYearCE":-9343,"species":[],"timeUnit":"cal yr BP"}],"siteName":"Pakitsoq outcrop"}],"studyCode":null,"studyName":"Pakitsoq Greenland Younger Dryas-Preboreal 14CH4 Data","studyNotes":"14C measurements in large-volume ice samples from \nPakitsoq, West Greenland. This data set contains measurements \nof 14C of methane made on ancient air extracted from large-volume \nglacial ice samples spanning the Younger Dryas - Preboreal climatic \ntransition about 11,600 years ago. The data set also contains \nsupporting measurements of 14C of carbon monoxide and 14C \nof carbon dioxide. \n\nThe measurements were made to test the hypothesis that catastrophic \ndestabilization of marine methane clathrates caused the methane \nincrease at the end of the Younger Dryas. The results suggested \nlittle to no change in 14CH4 over the time of the methane increase, \narguing against major clathrate involvement.\n\nThe ice samples were collected between Jul 1 and Aug 15, 2005. \n\nINSTRUMENT AND METHOD DESCRIPTION\nThe field and analytical system for determinations of 14CH4 \nin large-volume glacial ice samples have been described in \n(Petrenko et al., 2008a; Petrenko et al., 2008b; \nPetrenko et al., 2009). This system involves the melt-extraction \nof occluded air from very large volumes of glacial ice or at the \nsampling / ice coring site. Briefly, the present field system \nconsists of a large chemically polished aluminum vacuum melting tank \n(~670 L internal volume) and a series vacuum and transfer pumps. \nThe ice is loaded into the tank, and the headspace is evacuated \nand flushed 3x with either ultra-high purity (UHP) air, nitrogen \nor argon. The ice is then melted, releasing the ancient air into \nthe headspace. The air is then extracted from the tank by clean \ndiaphragm transfer pumps and stored in electropolished stainless \nsteel canisters for further laboratory handling and analyses. \nIn the laboratory, the air is first processed through a system \nthat converts either CH4 or CO to CO2, and captures this CO2 \nfor further handling. In the case of CH4 processing, H2O, CO2, \nN2O and other condensibles are first removed by a series of traps \nat liquid nitrogen temperature. CO is then quantitatively oxidized \nto CO2 by the Sofonocat reagent and subsequently removed by further \ncryotraps. CH4 is then combusted to CO2 by passing the air through \na 800°C furnace containing platinized quartz wool. The CH4-derived \nCO2 is then captured. This CO2 is then converted to graphite over \nultra-high-purity iron powder and subsequently measured for 14C \nby AMS. The combined procedural 14CH4 blank for all steps of \nsampling handling was determined to be 0.75 ± 0.38 pMC, \non the basis of 72 processed blank and standard samples \n(Petrenko et al., 2008b). For CO analyses, the sample handling \nis very similar except that the air bypasses Sofnocat, \nand the furnace temperature is reduced from 800 to 150°C. \nThis allows for complete combustion of CO while CH4 passes \nthrough unaffected. CO2 derived from CO was diluted with 14-C \nfree CO2 to increase the carbon mass to allow for a 14C measurement.\nFor sample 14CO2 measurements, CO2 was extracted cryogenically \nfrom ~0.5 L of air.\n\nDATA COLLECTION AND PROCESSING\nThe 14CH4 data are corrected the procedural blank. Where indicated, \n14CH4 data are also corrected for cosmogenic 14C production in ice. \nFor 14CO, corrections are applied for ambient air inclusion \nand processing blank.  For 14CO2, processing blank corrections \nare applied where indicated. \n\n","version":"1.0","xmlId":"10317"}