{"NOAAStudyId":"10290","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":"2011-01-27","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-10290.xml","doi":null,"earliestYearBP":19386,"earliestYearCE":-17436,"entryId":"noaa-other-10290","funding":[{"fundingAgency":"Leverhulme Trust","fundingGrant":null}],"investigators":"Chase, B.M.; Quick, L.J.; Meadows, M.E.; Scott, L.; Thomas, D.S.G.; Reimer, P.J.","mostRecentYearBP":7261,"mostRecentYearCE":-5311,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/10290","originalSource":null,"publication":[{"abstract":"Our ability to identify the timing and extent of past major \nclimate fluctuations is central to understanding changes in \nthe global climate system. Of the events that have occurred \nin recent geological time, the Younger Dryas (YD, 13-11.5 ka), \nan abrupt return to near-glacial conditions during the last \nglacial-interglacial transition (ca. 18-11.5 ka), is one \nof the most widely reported. While this event is apparent \nthroughout the Northern Hemisphere (Peteet, 1995), evidence \nfor its occurrence in the Southern Hemisphere remains \nequivocal due to a lack of well-dated terrestrial records. \nHere we report high-resolution stable carbon and nitrogen \nisotope records obtained from a rock hyrax midden, revealing \nthe first unequivocal terrestrial manifestation of the YD \nfrom the southern African subtropics. These results provide \nkey evidence for the relative influence of the YD, and suggest \nthat a subtropical-temperate transition zone existed along \nthe oceanic Subtropical Front (~41°S) across the Southern \nHemisphere, with the Northern Hemisphere exerting a strong \ninfluence on all but the higher latitudes of the Southern \nHemisphere after the Heinrich Stadial 1 (15 ka). \n","author":null,"citation":"Chase, B.M., L.J. Quick, M.E. Meadows, L. Scott, D.S.G. Thomas, \nand P.J. Reimer. 2011. \nLate-glacial interhemispheric climate dynamics revealed \nin South African hyrax middens. \nGeology, Vol. 39, No. 1, pp. 19-22, January 2011. \ndoi:10.1130/G31129.1 \n","edition":null,"identifier":{"id":"10.1130/G31129.1","type":"doi","url":"http://dx.doi.org/10.1130/G31129.1"},"issue":null,"journal":"Geology","pages":null,"pubRank":"1","pubYear":2011,"reportNumber":null,"title":"Late-glacial interhemispheric climate dynamics revealed  in South African hyrax middens","type":"publication","volume":null}],"reconstruction":"N","scienceKeywords":["Younger Dryas"],"site":[{"NOAASiteId":"36912","geo":{"geoType":"Feature","geometry":{"coordinates":["-32.446","19.221"],"type":"POINT"},"properties":{"easternmostLongitude":"19.221","maxElevationMeters":null,"minElevationMeters":null,"northernmostLatitude":"-32.446","southernmostLatitude":"-32.446","westernmostLongitude":"19.221"}},"locationName":"Continent>Africa>Southern Africa>South Africa","mappable":"Y","paleoData":[{"NOAADataTableId":"19077","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>others"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/midden/africa/de-rif2011iso.txt","linkText":"de-rif2011iso.txt","urlDescription":"Data","variables":[]},{"NOAAKeywords":["earth science>paleoclimate>others"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/midden/africa/de-rif2011iso.xls","linkText":"de-rif2011iso.xls","urlDescription":"Data","variables":[]}],"dataTableName":"DR001","dataTableNotes":null,"earliestYear":19386,"earliestYearBP":19386,"earliestYearCE":-17436,"mostRecentYear":7261,"mostRecentYearBP":7261,"mostRecentYearCE":-5311,"species":[],"timeUnit":"cal yr BP"}],"siteName":"De Rif"}],"studyCode":null,"studyName":"South Africa Deglacial Hyrax Midden Stable Isotope Data ","studyNotes":"Here we present stable carbon and nitrogen isotope data obtained \nfrom a rock hyrax (Procavia capensis) midden recovered from the \nCederberg Mountains of South Africa's Western Cape \n(32.446°S, 19.221°E). Located in the core of southern Africa's \nwinter rainfall zone (sensu Chase and Meadows (2007)), the site \npresently receives c. 380 mm yr-1 of rainfall with >80% falling \nbetween April and October. This marked seasonality is a product \nof the annual expansions and migrations of westerly storm tracks \nand associated frontal systems. Each winter these systems bring \nrain to southwestern Africa and each summer, as they contract \npoleward, their influence is replaced by the southward displacement \nof the South Atlantic Anticyclone and the development of coastal \nupwelling cells. The behaviour and influence of these systems on \nterrestrial environments over centennial to multi-millennial \ntimescales, however, remains largely unresolved.\n\nAccelerator mass spectrometry radiocarbon analyses of 10 samples \nfrom a 400 mm section of the De Rif midden indicate that it was \ndeposited between ca. 19,500 and 7300 cal yr B.P., spanning the \nentire Last Glacial-Interglacial Transition (LGIT). Further, the \ndistribution of ages as a function of depth shows that accumulation \nthroughout this period was broadly continuous, with no hiatuses \nindicated. Upper (0-70 mm) and lower (235-400 mm) sections are \ncomposed primarily of urine and accumulated at a rate of ~20–30 \num yr-1. Separating these sections is a 165-mm-thick layer that \ncontains a greater admixture of fecal pellets, which increased \nthe rate of deposition to ~94 um yr-1. Samples for stable isotope \nanalysis were drilled by hand with a 1-mm-diameter drill bit \nwith an average sample interval of 1.5 mm. The d15N values vary \nfrom 5.3‰ to -2.3‰. Among herbivores, such 15N abundance in \nanimal tissues is influenced by climate, diet, and/or physiology \n(Ambrose and DeNiro, 1986; Heaton et al., 1986). While many studies \nhave focused on the possible effects of animal metabolism on the \nsignal (Ambrose and DeNiro, 1986), studies of d15N in plants \nacross aridity gradients indicate clear correlations between \nenriched d15N and decreased rainfall (Murphy and Bowman, 2006; \nSchwarcz et al., 1999), suggesting that metabolism per se may \nhave negligible or relatively minor influence on the signal. \nIn particular, spatially extensive studies of d15N in both grass \nand kangaroo bone from across Australia reveal a strong, consistent \nrelationship between plant and bone d15N values, suggesting that \nwater availability, through its influence on the isotopic signature \nof consumed vegetation, is the primary control on animal d15N, \nwith metabolism having no clear effect (Murphy and Bowman, 2006). \nThese findings are supported by stable isotope records obtained \nfrom hyrax middens in Namibia, which show strong similarities \nbetween variations in d15N and a range of paleoenvironmental \nproxies reflecting changes in precipitation over multimillennial \ntime scales (Chase et al., 2009). \n\nThe d13C values from the midden vary between -28.3‰ and -26.9‰. \nAs a reflection of hyrax diet, these values indicate that the site \nhas hosted a predominantly to purely C3 vegetation throughout the \nrecorded period. This ecosystem stability over time provides a \nunique opportunity for variations in d13C to be used as a proxy \nfor climate rather than vegetation. Although variations in d13C \nin middens are often interpreted in terms of changing proportions \nof C3 versus C4 plants in the landscape (Scott and Vogel, 2000), \nin ecosystems supporting only C3 plants, variations in d13C are \nprimarily a function of leaf-level changes in water-use efficiency \n(Ehleringer and Cooper, 1988). Thus, the d13C variations in the \nDe Rif hyrax midden are interpreted as primarily reflecting \nchanges in effective precipitation. This interpretation is \nsupported by the strong similarities that are evident between \nthe d13C and d15N records (and argues against a significant \ninfluence of long-term changes in atmospheric CO2; Arens et al., \n2000), providing mutual validation that climate is the primary \ndeterminant of the observed signals.\n","version":"1.0","xmlId":"8964"}