# Saharan dust fluxes over the last 22 ka in the Bahamas and central tropical Atlantic #----------------------------------------------------------------------- # World Data Center for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # NOTE: Please cite original publication, online resource and date accessed when using this data. # If there is no publication information, please cite Investigator, title, online resource and date accessed. # # Description/Documentation lines begin with # # Data lines have no # # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/20775 # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/by_contributor/williams2016/williams2016-100-103ggc-geochem.txt # # Archive: Paleoceanography # # Parameter_Keywords: radiogenic isotope, geochemistry #--------------------------------------- # Contribution_Date # Date: 2016-11-17 #--------------------------------------- # Title # Study_Name: Saharan dust fluxes over the last 22 ka in the Bahamas and central tropical Atlantic #--------------------------------------- # Investigators # Investigators: Williams, Ross H.; McGee, David; Kinsley, Christopher W.; Ridley, David A.; Hu, Shineng; Fedorov, Alexey; Tal, Irit; Murray, Richard W.; deMenocal, Peter B. #--------------------------------------- # Description and Notes # Description: Dust fluxes spanning the last 22 ka determined by Th-normalization in cores in the Bahamas and central tropical Atlantic # Provided Keywords: Saharan dust; Bahamas; North Atlantic; Th-normalization; Last Glacial Maximum; African Humid Period; Holocene #--------------------------------------- # Publication # Authors: R.H. Williams, D. McGee, D.A. Ridley, C.W. Kinsley, S. Hu, A. Fedorov, I. Tal, R. Murray, and P.B. deMenocal # Published_Date_or_Year: 2016 # Published_Title: Glacial to Holocene changes in trans-Atlantic Saharan dust transport and dust-climate feedbacks # Journal_Name: Science Advances # Volume: 2 # Edition: # Issue: # Pages: # Report Number: # DOI: 10.1126/sciadv.1600445 # Online_Resource: # Full_Citation: # Abstract: 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. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: NSF # Grant: OCE-1030784, OCE-09277247 #--------------------------------------- # Funding_Agency # Funding_Agency_Name: NASA # Grant: NN14AP38G #--------------------------------------- # Site Information # Site_Name: OCE205-2 100GGC and 103GGC # Location: Bahamas # Country: # Northernmost_Latitude: 26.0703 # Southernmost_Latitude: 26.0612 # Easternmost_Longitude: -78.0277 # Westernmost_Longitude: -78.05617 # Elevation: #--------------------------------------- # Data_Collection # Collection_Name: OCE205-2 100GGC-103GGC Geochem Williams2016 # First_Year: # Last_Year: # Time_Unit: # Core_Length: # Notes: Ages for cores OCE205-2 100GGC and 103GGC previously published by Came et al. (2003; 2008) #--------------------------------------- # Chronology_Information # Chronology: # Ages for cores OCE205-2 100GGC and 103GGC previously published by Came et al. (2003; 2008) # #--------------------------------------- # Variables # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) ## core core ID,,,unitless,,,,,C ## depth_top_cm Depth top,,,cm,,,,,N ## depth_bottom_cm Depth bottom,,,cm,,,,,N ## Zr Zircon,detrital,,µg/g,,Paleoceanography,,instrument: inductively coupled plasma mass spectrometer,N ## Sc Scandium,detrital,,µg/g,,Paleoceanography,,instrument: inductively coupled plasma mass spectrometer,N ## Th Thorium,detrital,,µg/g,,Paleoceanography,,instrument: inductively coupled plasma mass spectrometer,N #------------------------ # Data # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Value: core depth_top_cm depth_bottom_cm Zr Sc Th OCE205-2 100GGC 14.5 15.5 4.78 0.36 0.41 OCE205-2 100GGC 14.5 15.5 5.16 0.4 0.42 OCE205-2 100GGC 34.5 35.5 5.3 0.47 0.44 OCE205-2 100GGC 54.5 55.5 4.93 0.38 0.38 OCE205-2 100GGC 54.5 55.5 4.91 0.37 0.39 OCE205-2 100GGC 73.5 74.5 4.91 0.37 0.4 OCE205-2 100GGC 94.5 95.5 5.24 0.54 0.48 OCE205-2 100GGC 113.5 114.5 9.86 1.48 1.28 OCE205-2 103GGC 97 98 6.54 0.8 0.71 OCE205-2 103GGC 101 102 6.89 0.83 0.74 OCE205-2 103GGC 105 106 7.64 1.00 0.86 OCE205-2 103GGC 110 111 7.07 0.91 0.83 OCE205-2 103GGC 114 115 8.37 1.28 1.18 OCE205-2 103GGC 118 119 9.32 1.36 1.22 OCE205-2 103GGC 122 123 14.06 2.16 1.95 OCE205-2 103GGC 126 127 15.06 2.37 2.1 OCE205-2 103GGC 129 130 14.41 2.21 2.08 OCE205-2 103GGC 134 135 13.3 2.08 1.95 OCE205-2 103GGC 139 140 16.64 1.87 1.67