{"NOAAStudyId":"11200","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":"2011-06-01","dataPublisher":"NOAA","dataType":"OTHER COLLECTIONS","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/other-collections","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-other-11200.xml","doi":null,"earliestYearBP":700000,"earliestYearCE":-698050,"entryId":"noaa-other-11200","funding":[{"fundingAgency":"US National Science Foundation","fundingGrant":"ATM-8614555, ATM-8909900"}],"investigators":"Oches, E.A.; McCoy, W.D.","mostRecentYearBP":0,"mostRecentYearCE":1950,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/11200","originalSource":null,"publication":[{"abstract":"Amino acid geochronology provides important chronostratigraphic \r\ninsight in the regional correlation and paleoclimatic evaluation \r\nof loess-paleosol sequences in the midwestern US, throughout western, \r\ncentral, and eastern Europe, and in China. In general, loess of \r\nthe last four glacial cycles, corresponding to marine oxygen-isotope \r\nstages (OIS) 2-4, 6, 8, and 10, respectively, can be distinguished \r\non the basis of alloisoleucine/isoleucine (A/I) ratios measured in \r\nfossil gastropod shells preserved in the loess. The racemization \r\nreaction is much slower in older samples, resulting in decreased \r\ntemporal resolution. In the midwestern US and Europe, it is not \r\npossible to confidently subdivide the last glacial cycle on the \r\nbasis of aminostratigraphic data. However, in China, where effective \r\ntemperatures were higher during the Late Pleistocene, loess above \r\nand below L1SS1, the OIS-3 interstadial paleosol, can be distinguished \r\nusing amino acid racemization data. \r\nWith improvements in analytical methods, multiple amino acid D/L \r\nenantiomers are now being measured using reverse-phase liquid \r\nchromatography. Aspartic acid racemizes at a higher rate than \r\nthe traditionally measured alloisoleucine/isoleucine diastereomers \r\nand can be measured more rapidly. This development offers hope for \r\nbetter temporal resolution and enhanced stratigraphic subdivision \r\nof loess units than has been achieved previously. \r\n","author":null,"citation":"Oches, E.A. and W.D. McCoy. 2001. \r\nHistorical developments and recent advances in amino acid \r\ngeochronology applied to loess research: examples from \r\nNorth America, Europe, and China. \r\nEarth-Science Reviews, Vol. 54, Issues 1-3, June 2001, pp. 173-192. \r\ndoi:10.1016/S0012-8252(01)00047-2 ","edition":null,"identifier":{"id":"10.1016/S0012-8252(01)00047-2 ","type":"doi","url":"http://dx.doi.org/10.1016/S0012-8252(01)00047-2 "},"issue":null,"journal":"Earth-Science Reviews","pages":null,"pubRank":"1","pubYear":2001,"reportNumber":null,"title":"Historical developments and recent advances in amino acid  geochronology applied to loess research: examples from  North America, Europe, and China","type":"publication","volume":null}],"reconstruction":"N","scienceKeywords":null,"site":[{"NOAASiteId":"48149","geo":{"geoType":"Feature","geometry":{"coordinates":["35.7","109.4"],"type":"POINT"},"properties":{"easternmostLongitude":"109.4","maxElevationMeters":null,"minElevationMeters":null,"northernmostLatitude":"35.7","southernmostLatitude":"35.7","westernmostLongitude":"109.4"}},"locationName":"Continent>Asia>Eastern Asia>China","mappable":"Y","paleoData":[{"NOAADataTableId":"19801","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>others"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/aar/oches2001loess/oches2001loess.txt","linkText":"oches2001loess.txt","urlDescription":"Data","variables":[]},{"NOAAKeywords":["earth science>paleoclimate>others"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/aar/oches2001loess/oches2001loess.xls","linkText":"oches2001loess.xls","urlDescription":"Data","variables":[]}],"dataTableName":"L1LL","dataTableNotes":null,"earliestYear":700000,"earliestYearBP":700000,"earliestYearCE":-698050,"mostRecentYear":0,"mostRecentYearBP":0,"mostRecentYearCE":1950,"species":[],"timeUnit":"cal yr BP"}],"siteName":"Luochuan"}],"studyCode":null,"studyName":"Chinese Loess Plateau 700KYr Amino Acid Racemization Data","studyNotes":"Alloisoleucine/isoleucine data from fossil snail shells recovered \nfrom loess strata of the Chinese loess plateau in the region near \nLuochuan, Shaanxi Province, China. \n\nFossil gastropod shells collected from large exposures of stratified \nloess and paleosols in the vicinity of Luochuan, Shaanxi Province, \nChina, are analyzed by cation-exchange HPLC to determine the extent \nof isoleucine epimerization.  Three of the sample sites (Lower Heimu, \nUpper Heimu and Potou) are within about three kilometers of the \nvillage of Luochuan and are near branches of a large, deep gully \nsystem (Heimugou).  The fourth site is at an excavation for a railroad \ngrade about 20 km southwest of Luochuan and close to the city of \nHuangling.  The ratio of D-alloisoleucine/L-isoleucine (AI) \nprogressively increases in shells from strata of increasing \nstratigraphic age over several loess (glacial) cycles from L1 \n(youngest) to L5 (oldest sampled for this report).  The AI values \nprovide clear discrimination of loess stratigraphic units L1, L2 and \nL3.  Although AI values continue to increase in units older than L3, \nresolution decreases.  Confounding the inevitable reduction of \nresolution with increasing age is the fact that shells are much less \nabundant in the older strata and, therefore, few shell samples were \nrecovered.  Due to this scarcity of data, the extent of isoleucine \nepimerization in shells from these older units remains poorly \ncharacterized.  On the other hand, the resolution in the youngest \nloess, L1, is good enough that it appears possible to discriminate \nbetween the two loess strata within it, L1LL1 and L1LL2. ","version":"1.0","xmlId":"9638"}