{"NOAAStudyId":"5454","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":"2007-01-01","dataPublisher":"NOAA","dataType":"PALEOLIMNOLOGY","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/lake","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-lake-5454.xml","doi":null,"earliestYearBP":26655,"earliestYearCE":-24705,"entryId":"noaa-lake-5454","funding":[],"investigators":"Peck, J.A.; Green, R.R.; Shanahan, T.; King, J.W.; Overpeck, J.T.; Scholz, C.A.","mostRecentYearBP":152,"mostRecentYearCE":1798,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/5454","originalSource":null,"publication":[{"abstract":"We report magnetic hysteresis results from sediment cores obtained from  Lake Bosumtwi, Ghana. As a hydrologically closed basin, the water budget  of Lake Bosumtwi is extremely sensitive to changes in the precipitation/ evapotranspiration balance. Lake Bosumtwi lies in the path of the seasonal  migration of the intertropical convergence zone (ITCZ); hence, the lake  is ideally situated to study monsoon variability in West Africa. Five  distinctive magnetic mineral zones (A-E) were identified in the 11-m-long  sediment cores that span the last 26,000 calendar years. Prior to 12  calendar (cal) ka, low concentrations of multidomain, high-coercivity  magnetic minerals are present. Three prominent shifts towards very high concentrations of high-coercivity iron sulfide (greigite) magnetic minerals  are centered at 12,470, 17,290, and 22,600 calendar years during the last  glacial period (magnetic zones D1-3). Between 12 and 3.2 cal ka, there is  an abrupt shift to moderately high concentrations of mixed multidomain  and single-domain, low-coercivity minerals and an organic-rich sapropel  lithology. Since 3.2 cal ka, the magnetic mineral parameters reveal a shift  to increased amounts of high-coercivity magnetic minerals.","author":null,"citation":"Peck, J.A., R.R. Green, T. Shanahan, J.W. King, J.T. Overpeck, C.A. Scholz. 2004. A magnetic mineral record of Late Quaternary tropical climate variability from Lake Bosumtwi, Ghana. Palaeogeography, Palaeoclimatology, Palaeoecology Vol. 215, pp. 37- 57","edition":null,"identifier":null,"issue":null,"journal":"Palaeogeography, Palaeoclimatology, Palaeoecology","pages":null,"pubRank":"1","pubYear":2004,"reportNumber":null,"title":"A magnetic mineral record of Late Quaternary tropical climate variability from Lake Bosumtwi, Ghana","type":"publication","volume":null}],"reconstruction":"N","scienceKeywords":null,"site":[{"NOAASiteId":"8890","geo":{"geoType":"Feature","geometry":{"coordinates":["6.5","-1.4167"],"type":"POINT"},"properties":{"easternmostLongitude":"-1.4167","maxElevationMeters":"99","minElevationMeters":"99","northernmostLatitude":"6.5","southernmostLatitude":"6.5","westernmostLongitude":"-1.4167"}},"locationName":"Continent>Africa>Western Africa>Ghana","mappable":"Y","paleoData":[{"NOAADataTableId":"7208","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth 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properties>coercivity"},{"cvAdditionalInfo":"Hcr/Hc","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>bulk geological material>sediment","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"dimensionless","cvWhat":"magnetic property>magnetic ratios>coercivity of remanence/coercivity"},{"cvAdditionalInfo":"Mrs/IS","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>bulk geological material>sediment","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"kiloampere per meter","cvWhat":"magnetic property>magnetic ratios>saturation isothermal remanent magnetization/initial magnetization slope"},{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>bulk geological material>sediment","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"dimensionless","cvWhat":"magnetic property>magnetic ratios>S-ratio"},{"cvAdditionalInfo":"Mrs","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>bulk geological material>sediment","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"milliampere square meter per kilogram","cvWhat":"magnetic property>magnetic moments>remanent magnetization>isothermal remanent magnetization>saturation isothermal remanent magnetization"}]},{"NOAAKeywords":["earth science>paleoclimate>paleolimnology>geochemistry"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/africa/bosumtwi2004.xls","linkText":"bosumtwi2004.xls","urlDescription":"Data","variables":[]}],"dataTableName":"Lake Bosumtwi BOSUMTW Mineral","dataTableNotes":null,"earliestYear":26655,"earliestYearBP":26655,"earliestYearCE":-24705,"mostRecentYear":152,"mostRecentYearBP":152,"mostRecentYearCE":1798,"species":[],"timeUnit":"cal yr BP"}],"siteName":"Lake Bosumtwi"}],"studyCode":null,"studyName":"Lake Bosumtwi, Ghana Late Quaternary Magnetic Mineral Data","studyNotes":"Physical property logging of whole core volumetric magnetic susceptibility and gammaray attenuation (an estimation of wet bulk density) was conducted on the piston cores using an automated Geotek multisensor core logger.","version":"1.0","xmlId":"629"}