{"NOAAStudyId":"17677","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":"2014-12-19","dataPublisher":"NOAA","dataType":"LAKE LEVELS","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/lake-level-reconstruction","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-lakelevel-17677.xml","doi":null,"earliestYearBP":127710,"earliestYearCE":-125760,"entryId":"noaa-lakelevel-17677","funding":[{"fundingAgency":"FWO-Vlaanderen (Belgium) ","fundingGrant":null}],"investigators":"Moernaut, J.; Verschuren, D.; Charlet, F; Kristen, I.; Fagot, M.; De Batist, M.","mostRecentYearBP":-60,"mostRecentYearCE":2010,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/17677","originalSource":null,"publication":[{"abstract":"Seismic-reflection data from crater lake Challa(Mt. Kilimanjaro, equatorial East Africa) reveal a ~210-m thick sedimentary infill containing distinct seismic-stratigraphic signatures of late-Quaternary lake-level fluctuations. Extrapolation of a well-constrained age model on the cored upper part of the sequence suggests that these lake-level fluctuations represent a detailed and continuous record of moisture-balance variation inequatorial East Africa over the last 140 kyr. This record indicates that the most severe aridity occurred during peak Penultimate glaciation immediately before ~128 kyr BP (coeval with Heinrich event 11) and during a Last Interglacial ‘megadrought’ period between ~114 and ~97 kyr BP; in comparison, Last Glacial Maximum (LGM) aridity was modest. It was preceded by ~75 000 years of relatively stable and moist climate conditions interrupted by eleven short-lived dry spells, five of which match the timing of Heinrich events 2 to 6. Climate history near the East African equator reflects variation in the precessional forcing of monsoon rainfall modulated by orbital eccentricity, but precession-driven moisture fluctuations were less extreme than those observed in northern and southern tropical Africa. The near-continuous moist climate from ~97 to 20.5 kyr BP recorded in the Lake Challa record contrasts with the trend towards greater aridity after ~70 kyr BP documented in equatorial West Africa. This long period of moist glacial climate and a short, relatively modest LGM drought can be attributed to greater independence of western Indian Ocean monsoon dynamics from northern high-latitude glaciation than those in the tropical Atlantic Ocean. This rather persistent moist glacial climate regime may have helped maintain high biodiversity in the tropical forest ecosystems of the Eastern Arc mountains in Tanzania.","author":{"name":"Moernaut, J.; Verschuren, D.; Charlet, F.; Kristen, I.;Fagot, M.; De Batist, M."},"citation":"Moernaut, J.; Verschuren, D.; Charlet, F.; Kristen, I.;Fagot, M.; De Batist, M. 2010. The seismic-stratigraphic record of lake-level fluctuations in Lake Challa: hydrological stability and change in equatorial East-Africa over the last 140 kyr. Earth and Planetary Science Letters, 290((1-2)), 214-223. ","edition":null,"identifier":null,"issue":"(1-2)","journal":"Earth and Planetary Science Letters","pages":"214-223","pubRank":"1","pubYear":2010,"reportNumber":null,"title":"The seismic-stratigraphic record of lake-level fluctuations in Lake Challa: hydrological stability and change in equatorial East-Africa over the last 140 kyr","type":"publication","volume":"290"}],"reconstruction":"N","scienceKeywords":["Monsoon"],"site":[{"NOAASiteId":"47999","geo":{"geoType":"Feature","geometry":{"coordinates":["-3.3167","37.7"],"type":"POINT"},"properties":{"easternmostLongitude":"37.7","maxElevationMeters":"880","minElevationMeters":"880","northernmostLatitude":"-3.3167","southernmostLatitude":"-3.3167","westernmostLongitude":"37.7"}},"locationName":"Continent>Africa>Eastern Africa>Kenya","mappable":"Y","paleoData":[{"NOAADataTableId":"27996","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>lake levels"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/lakelevels/africa/eastafrica/moernaut2010-lakechalla.txt","linkText":"moernaut2010-lakechalla.txt","urlDescription":"Lake Levels Data","variables":[{"cvAdditionalInfo":null,"cvDataType":"LAKE LEVELS|PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Character","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"dimensionless","cvWhat":"earth system variable>hydrographic variable>lake level"},{"cvAdditionalInfo":null,"cvDataType":"LAKE LEVELS|PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Character","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":null,"cvWhat":"sampling metadata>notes"},{"cvAdditionalInfo":null,"cvDataType":"LAKE LEVELS|PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar kiloyear before present","cvWhat":"age variable>age>age at sample end"},{"cvAdditionalInfo":"minimum age","cvDataType":"LAKE LEVELS|PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar kiloyear before present","cvWhat":"age variable>age>age at sample end"},{"cvAdditionalInfo":"maximum age","cvDataType":"LAKE LEVELS|PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar kiloyear before present","cvWhat":"age variable>age>age at sample end"},{"cvAdditionalInfo":null,"cvDataType":"LAKE LEVELS|PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar kiloyear before present","cvWhat":"age variable>age>age at sample start"},{"cvAdditionalInfo":"minimum age","cvDataType":"LAKE LEVELS|PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar kiloyear before present","cvWhat":"age variable>age>age at sample start"},{"cvAdditionalInfo":"maximum age","cvDataType":"LAKE LEVELS|PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar kiloyear before present","cvWhat":"age variable>age>age at sample start"},{"cvAdditionalInfo":"values used in plot","cvDataType":"LAKE LEVELS|PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"dimensionless","cvWhat":"earth system variable>hydrographic variable>lake level"}]}],"dataTableName":"lake-challa-recon","dataTableNotes":"Lake Challa 130kyr lake-level reconstruction.  Reconstruction based on the succession of draped (highstand) and focused (lowstand) units in seismic stratigraphy, and landslide deposits (lowstands); see Moernaut et al. (2010), Earth and Planetary Science Letters 290, 214-223. Lake depth ('lake-level-plot-value') is on a relative scale. For illustrative purposes the duration of an MWE/MWD event is arbritarily set at 0.04 kyr.  Chronology based on 1) combined 210Pb- and 14C-dating of the cored upper portion (last 25kyr, from Seismic unit/feature U1 to MWE2; 'min' and 'max' represent two-sigma errors on the modeled age-depth relationship); see Blaauw et al. (2012) Quaternary Science Reviews 30, 3043-3059; and 2) extrapolation of the core’s age model to the deeper seismic sequence (from Seismic unit/feature U4 to unconformity), assuming a mean acoustic velocity of 1500 m/s for Units 1 to 6 and 1550 m/s for Units 7 to 13, association of unit geometry with sedimentation rate variations (obtained on cored interval), and applying an exponential compaction correction based on the measured porosity gradient down-core; see Moernaut et al. (2010), Earth and Planetary Science Letters 290, 214-223.","earliestYear":127710,"earliestYearBP":127710,"earliestYearCE":-125760,"mostRecentYear":-60,"mostRecentYearBP":-60,"mostRecentYearCE":2010,"species":[],"timeUnit":"cal yr BP"}],"siteName":"Lake Challa"}],"studyCode":null,"studyName":"The seismic-stratigraphic record of lake-level fluctuations in Lake Challa: hydrological stability and change in equatorial East-Africa over the last 140 kyr","studyNotes":"Lake Challa 130kyr lake-level reconstruction. Reconstruction based on the succession of draped (highstand) and focused (lowstand) units in seismic stratigraphy, and landslide deposits (lowstands); see Moernaut et al. (2010), Earth and Planetary Science Letters 290, 214-223. \nContact: Dirk Verschuren, dirk.verschuren@UGent.be","version":"1.0","xmlId":"15342"}