{"NOAAStudyId":"24990","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":"2018-08-26","dataPublisher":"NOAA","dataType":"CLIMATE FORCING","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/climate-forcing","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-forcing-24990.xml","doi":null,"earliestYearBP":16760000,"earliestYearCE":-16758050,"entryId":"noaa-forcing-24990","funding":[{"fundingAgency":"National Key Research and Development Program of China","fundingGrant":"2016YFE0109500"},{"fundingAgency":"National Natural Science Foundation China","fundingGrant":"41761144063, 41672157, 41422204"},{"fundingAgency":"State Key Laboratory of Loess and Quaternary Geology of China","fundingGrant":null},{"fundingAgency":"Chinese Academy of Sciences","fundingGrant":"SKLLQG1608"},{"fundingAgency":"US National Science Foundation","fundingGrant":"1545859, EAR-1156134, EAR-1252064"}],"investigators":"Ji, S.; Nie, J.S.; Lechler, A.; Huntington, K.W.; Heitmann, E.O.; Breecker, D.O.","mostRecentYearBP":7140000,"mostRecentYearCE":-7138050,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/24990","originalSource":null,"publication":[{"abstract":"Understanding the future trajectory of Earth's climate requires knowledge of shifts in atmospheric CO2 concentrations during past warm episodes. The Miocene Climatic Optimum (MCO, ~17-14 Ma) was likely the warmest episode of the past 25 Myr, and thus atmospheric CO2 concentrations during this interval are of particular interest. However, CO2 records across the middle Miocene are rather scattered and data are notably sparse for the latter part of the MCO. Here we present a paleosol-based CO2 record from the Tianshui Basin, northern China, spanning 17-7 Ma. Our results show elevated mean CO2 during the second half of the MCO corresponding with some of the lowest benthic d18O values and highest benthic d13C values, as part of the \"Monterey excursion\", published for the Neogene. This result supports the idea that the broader Monterey excursion was primarily associated with a CO2 maximum, not carbon burial and CO2 minima as previously interpreted. The new CO2 record, along with previous CO2 records based on paleosols, stomata and foraminiferal boron isotope compositions, also suggests that mean CO2 across the MCO was elevated compared with the immediately following (post-MCO, 14-11 Ma, >80% probability) and immediately preceding (pre-MCO, 20-17 Ma, 70% probability) time periods. The most probable magnitude of the MCO CO2 peak is 20% higher than post-MCO and 12.5% higher than pre-MCO levels. Larger factors, of perhaps 50% higher CO2, likely apply in narrower (<1 Myr) time slices. CO2 records from each proxy individually support the conclusion of modestly elevated MCO CO2, although large temporal gaps exist in records from any one proxy. Using all proxies together, we estimate average MCO CO2 of 375+150/-100 (84th and 16th percentile) ppm. Although mean MCO CO2 was elevated, the MCO was also characterized by highly variable CO2. In addition, determinations from all three proxies suggest that at times during the MCO, CO2 levels were as low as they were following the ice sheet expansion of the Miocene Climate Transition. Furthermore, pre-MCO CO2 levels are indistinguishable from post-MCO CO2 levels (60% probability of pre-MCO CO2 > post-MCO CO2), despite significantly lower benthic d18O values during the former. We conclude that 1) the MCO was a period of slightly elevated and highly variable CO2 compared with the immediately preceding and following intervals, and 2) neither CO2 decrease, orbitally-controlled seasonality over Antarctica nor the confluence of these factors was sufficient to cause Miocene Climate Transition ice sheet expansion. Rather strengthening of the Antarctic Circumpolar Current and Southern Ocean cooling related to closure of the eastern Tethys was a necessary first step.","author":{"name":"Shunchuan Ji, Junsheng Nie, Alex Lechler, Katharine W. Huntington, Emma O. Heitmann, Daniel O. Breecker"},"citation":"Shunchuan Ji, Junsheng Nie, Alex Lechler, Katharine W. Huntington, Emma O. Heitmann, Daniel O. Breecker. 2018. A symmetrical CO2 peak and asymmetrical climate change during the middle Miocene. Earth and Planetary Science Letters, 499, 134-144. doi: 10.1016/j.epsl.2018.07.011","edition":null,"identifier":{"id":"10.1016/j.epsl.2018.07.011","type":"doi","url":"http://dx.doi.org/10.1016/j.epsl.2018.07.011"},"issue":null,"journal":"Earth and Planetary Science Letters","pages":"134-144","pubRank":"1","pubYear":2018,"reportNumber":null,"title":"A symmetrical CO2 peak and asymmetrical climate change during the middle Miocene","type":"publication","volume":"499"}],"reconstruction":"N","scienceKeywords":null,"site":[{"NOAASiteId":"57701","geo":{"geoType":"Feature","geometry":{"coordinates":["34.967","105.567"],"type":"POINT"},"properties":{"easternmostLongitude":"105.567","maxElevationMeters":null,"minElevationMeters":null,"northernmostLatitude":"34.967","southernmostLatitude":"34.967","westernmostLongitude":"105.567"}},"locationName":"Continent>Asia>Eastern Asia>China","mappable":"Y","paleoData":[{"NOAADataTableId":"36793","coreLengthMeters":249,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>climate forcing>carbon dioxide"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/climate_forcing/trace_gases/Paleo-pCO2/ji2018paleosol.txt","linkText":"Tianshui Basin Paleosol d13C and pCO2 Data","urlDescription":"NOAA Template File","variables":[{"cvAdditionalInfo":"from paleosols","cvDataType":"CLIMATE FORCING","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":"median; from paleosols","cvDataType":"CLIMATE FORCING","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":"2.5 percentile; from paleosols","cvDataType":"CLIMATE FORCING","cvDetail":null,"cvError":"percentile","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":"97.5 percentile; from paleosols","cvDataType":"CLIMATE FORCING","cvDetail":null,"cvError":"percentile","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":"CLIMATE FORCING","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"million years ago","cvWhat":"age variable>age"}]},{"NOAAKeywords":["earth science>paleoclimate>climate forcing>carbon dioxide"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/climate_forcing/trace_gases/Paleo-pCO2/ji2018paleosol.xlsx","linkText":"Tianshui Basin Paleosol d13C and pCO2 Data","urlDescription":"Excel File","variables":[]}],"dataTableName":"Ji2018paleosol","dataTableNotes":null,"earliestYear":16760000,"earliestYearBP":16760000,"earliestYearCE":-16758050,"mostRecentYear":7140000,"mostRecentYearBP":7140000,"mostRecentYearCE":-7138050,"species":[],"timeUnit":"cal yr BP"}],"siteName":"Yanwan section"}],"studyCode":null,"studyName":"Paleo-pCO2 Database Tianshui Basin Middle Miocene Paleosol d13C Data","studyNotes":"Carbon isotope (d13C) data and CO2 estimates from Miocene paleosols of the Yanwan section, Tianshui Basin, Gansu, China, contributed to the Paleo-pCO2 Database","version":"1.0","xmlId":"23134"}