Saharan dust fluxes over the last 22 ka in the Bahamas and central tropical Atlantic Williams, R.H.; McGee, D.; Kinsley, C.W.; Ridley, D.A.; Hu, S.; Fedorov, A.V.; Tal, I.; Murray, R.W.; deMenocal, P.B. Williams, R.H. McGee, D. Kinsley, C.W. Ridley, D.A. Hu, S. Fedorov, A.V. Tal, I. Murray, R.W. deMenocal, P.B. earth science/paleoclimate/paleoceanography (232Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment) earth science/paleoclimate/paleoceanography (232Th,sediment,one standard deviation,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment) earth science/paleoclimate/paleoceanography (age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (230Th,sediment,one standard deviation,gram per square centimeter per kiloyear,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,230Th normalized sediment flux) earth science/paleoclimate/paleoceanography (dust,null,null,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,dust flux; assumes 232Th concentration of 13.7 ± 1.0 µg/g in dust) earth science/paleoclimate/paleoceanography (dust,null,one standard deviation,gram per square centimeter per kiloyear,null,paleoceanography,null,null,N,dust flux) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,C,Core) earth science/paleoclimate/paleoceanography (230Th,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment) earth science/paleoclimate/paleoceanography (depth,null,null,meter,null,paleoceanography,null,null,N,depth of water column) earth science/paleoclimate/paleoceanography (230Th,sediment,one standard deviation,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment) earth science/paleoclimate/paleoceanography (238U,sediment,one standard deviation,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment) earth science/paleoclimate/paleoceanography (zircon,sediment,null,microgram per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment) earth science/paleoclimate/paleoceanography (depth at sample start,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (thorium,sediment,null,microgram per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment) earth science/paleoclimate/paleoceanography (notes,null,null,null,null,paleoceanography,null,null,C,core ID) earth science/paleoclimate/paleoceanography (230Th,sediment,null,gram per square centimeter per kiloyear,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,230Th normalized sediment flux; assumes detrital U/Th activity ratio of 0.6 ± 0.1) earth science/paleoclimate/paleoceanography (232Th,sediment,null,microgram per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (238U,sediment,null,disintegration per minute per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment) earth science/paleoclimate/paleoceanography (depth at sample end,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (scandium,sediment,null,microgram per gram,null,paleoceanography,null,inductively-coupled plasma mass spectrometry,N,detrital sediment) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (OCE205-2 100GGC and 103GGC>LATITUDE 26.065>LONGITUDE -78.041) (VM20-234>LATITUDE 5.33>LONGITUDE -33.03) Saharan mineral dust exported over the tropical North Atlantic is thought to have significant impacts on regional climate and ecosystems, but limited data exists documenting past changes in long-range dust transport. This data gap limits investigations of the role of Saharan dust in past climate change, in particular during the early Holocene, when climate models consistently underestimate the intensification of the West African monsoon documented by paleorecords. Here we present reconstructions of African dust deposition in sediments from the Bahamas and the tropical North Atlantic spanning the last 23,000 years. Both sites show early Holocene dust fluxes 40-50% lower than recent values and maximum dust fluxes during the deglaciation, demonstrating strong agreement with records from the northwest African margin. These quantitative estimates of trans-Atlantic dust transport offer important constraints on past changes in dust-related radiative and biogeochemical impacts. Using idealized climate model experiments to investigate the response to reductions in Saharan dust's radiative forcing over the tropical North Atlantic, we find that small (0.15 °C) dust-related increases in regional sea surface temperatures are sufficient to cause significant northward shifts in the Atlantic Intertropical Convergence Zone, increased precipitation in the western Sahel and Sahara, and reductions in easterly and northeasterly winds over dust source regions. Our results suggest that the amplifying feedback of dust on sea surface temperatures and regional climate may be significant, and that accurate simulation of dust's radiative effects is likely essential to improving model representations of past and future precipitation variations in North Africa. STUDY NOTES: Provided Keywords: Saharan dust; Bahamas; North Atlantic; Th-normalization; Last Glacial Maximum; African Humid Period; Holocene NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Williams, R.H. Investigator : McGee, D. Investigator : Kinsley, C.W. Investigator : Ridley, D.A. Investigator : Hu, S. Investigator : Fedorov, A.V. Investigator : Tal, I. Investigator : Murray, R.W. Investigator : deMenocal, P.B. 2016-11-16 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/20775 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-100-103ggc-geochem.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-vm20-234.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-100-103ggc-iso.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-100-103ggc-geochem.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-vm20-234.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-100-103ggc-iso.txt English https://www.ncdc.noaa.gov/paleo/study/20775 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-100-103ggc-geochem.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-vm20-234.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/williams2016/williams2016-100-103ggc-iso.txt Williams, R.H., D. McGee, D.A. Ridley, C.W. Kinsley, S. Hu, A. Fedorov, I. Tal, R. Murray, and P.B. deMenocal2016Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacksScience Advances210.1126/sciadv.1600445 START YEAR: 22248 cal yr BP * END YEAR: 288 cal yr BP -78.05617 5.33 -33.03 26.0703