The magnitude, timing and abruptness of changes in North African dust deposition over the last 20,000 yr

noaa-ocean-16397 North African Dust Deposition Fluxes Over the last 20,000 years McGee, D.; deMenocal, P.B.; Winckler, G.; Stuut, J.-B.W.; Bradtmiller, L.I. North African Dust Deposition Fluxes Over the last 20,000 years 2014-04-29 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/16397 Investigator D. McGee Investigator P.B. deMenocal Investigator G. Winckler Investigator J.-B.W. Stuut Investigator L.I. Bradtmiller earth science paleoclimate paleoceanography notes,null,null,null,null,paleoceanography,null,null,C,null earth science paleoclimate paleoceanography age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography dust,sediment,null,percent,null,paleoceanography,null,null,N,detrital sediment earth science paleoclimate paleoceanography 230Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,isotope dilution mass spectrometry,N,null earth science paleoclimate paleoceanography dust,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography mineral matter,null,null,percent,null,paleoceanography,null,null,N,detrital/clastics only? earth science paleoclimate paleoceanography accumulation rate,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,sediment flux; Calculated by 230Thxs normalization using detrital U/Th activity ratio of 0.7 ± 0.1 earth science paleoclimate paleoceanography accumulation rate,sediment,one standard deviation,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,sediment flux earth science paleoclimate paleoceanography 232Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,isotope dilution mass spectrometry,N,null earth science paleoclimate paleoceanography 238U,sediment,null,disintegration per minute per gram,null,paleoceanography,null,isotope dilution mass spectrometry,N,null earth science paleoclimate paleoceanography depth,null,null,centimeter,null,paleoceanography,null,null,N,null earth science paleoclimate paleocean radiogenic isotope earth science paleoclimate paleocean physical properties geoscientificInformation 21933 cal yr BP 358 cal yr BP Complete 19.363 30.879833 -17.860217 -10.629833 -2771 -1258 Ocean Atlantic Ocean North Atlantic Ocean OCE437-07-GC68>LATITUDE 19.363>LONGITUDE -17.282333 Ocean Atlantic Ocean North Atlantic Ocean OCE437-07-GC27>LATITUDE 30.879833>LONGITUDE -10.629833 Ocean Atlantic Ocean North Atlantic Ocean OCE437-07-GC49>LATITUDE 23.206167>LONGITUDE -17.854167 Ocean Atlantic Ocean North Atlantic Ocean OCE437-07-GC37>LATITUDE 26.81595>LONGITUDE -15.117717 Ocean Atlantic Ocean North Atlantic Ocean OCE437-07-GC66>LATITUDE 19.944>LONGITUDE -17.860217 None 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. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII McGee, D., P.B. deMenocal, G. Winckler, J.B.W. Stuut and L.I. Bradtmiller 2013 The magnitude, timing and abruptness of changes in North African dust deposition over the last 20,000 yr Earth and Planetary Science Letters 371-372 163-176 10.1016/j.epsl.2013.03.054

Reconstructions of eolian dust accumulation in northwest African margin sediments provide important continuous records of past changes in atmospheric circulation and aridity in the region. Existing records indicate dramatic changes in North African dust emissions over the last 20 ka, but the limited spatial extent of these records and the lack of high-resolution flux data do not allow us to determine whether changes in dust deposition occurred with similar timing, magnitude and abruptness throughout northwest Africa. Here we present new records from a meridional transect of cores stretching from 31°N to 19°N along the northwest African margin. By combining grain size endmember modeling with 230Th-normalized fluxes for the first time, we are able to document spatial and temporal changes in dust deposition under the North African dust plume throughout the last 20 ka. Our results provide quantitative estimates of the magnitude of dust flux changes associated with Heinrich Stadial 1, the Younger Dryas, and the African Humid Period (AHP; ~11.7-5 ka), offering robust targets for model-based estimates of the climatic and biogeochemical impacts of past changes in North African dust emissions. Our data suggest that dust fluxes between 8-6 ka were a factor of ~5 lower than average fluxes during the last 2 ka. Using a simple model to estimate the effects of bioturbation on dust input signals, we find that our data are consistent with abrupt, synchronous changes in dust fluxes in all cores at the beginning and end of the AHP. The mean ages of these transitions are 11.8 ± 0.2 ka (1s) and 4.9 ± 0.2 ka, respectively. STUDY NOTES: Ages determined by P_Sequence routine in Oxcal 4.2. Uncertainties on sediment flux are dominated by correction for detrital 230Th. Dust fraction is sum of variables EM2 and EM1 contributions to detrital fraction. Dust flux calculated as sediment flux*detrital%*dust fraction.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mcgee2013/mcgee2013-gc27-grain.txt Formatted Text File; OCE437-07-GC27 Grain Size Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mcgee2013/mcgee2013-gc68-flux.txt Formatted Text File; OCE437-07-GC68 Dust Flux Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mcgee2013/mcgee2013-gc68-grain.txt Formatted Text File; OCE437-07-GC68 Grain Size Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mcgee2013/mcgee2013-gc37-flux.txt Formatted Text File; OCE437-07-GC37 Dust Flux Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mcgee2013/mcgee2013-gc37-grain.txt Formatted Text File; OCE437-07-GC37 Grain Size Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mcgee2013/mcgee2013-gc66-grain.txt Formatted Text File; OCE437-07-GC66 Grain Size Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mcgee2013/mcgee2013-gc27-flux.txt Formatted Text File; OCE437-07-GC27 Dust Flux Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mcgee2013/mcgee2013-gc49-grain.txt Formatted Text File; OCE437-07-GC49 Grain Size Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mcgee2013/mcgee2013-gc49-flux.txt Formatted Text File; OCE437-07-GC49 Dust Flux Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/mcgee2013/mcgee2013-gc66-flux.txt Formatted Text File; OCE437-07-GC66 Dust Flux Data USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11