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Orbital- and Millennial-Scale Variability in Northwest African Dust Emissions Over the Past 67,000 years
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  • Christopher W. Kinsley,
  • Louisa Irene Bradtmiller,
  • David McGee,
  • Michael Galgay,
  • Jan-Berend Willem Stuut,
  • Rik Tjallingii,
  • Gisela Winckler,
  • Peter B. deMenocal
Christopher W. Kinsley
Massachusetts Institute of Technology

Corresponding Author:[email protected]

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Louisa Irene Bradtmiller
Macalester College
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David McGee
MIT
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Michael Galgay
Macalester College
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Jan-Berend Willem Stuut
NIOZ - Royal Netherlands Institute for Sea Research, and Utrecht University
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Rik Tjallingii
GFZ German Research Centre for Geosciences
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Gisela Winckler
Columbia University
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Peter B. deMenocal
Lamont-Doherty Earth Observatory
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Abstract

Reconstructions of aeolian dust flux to West African margin sediments can be used to explore changing atmospheric circulation and hydroclimate over North Africa on millennial to orbital timescales. Here, we extend West African margin dust flux records back to 35 ka in a transect of core sites from 19°N to 27°N, and back to 67 ka at Ocean Drilling Program (ODP) Hole 658C, in order to explore the interplay of orbital and high-latitude forcings on North African climate and make quantitative estimates of dust flux during the core of the Last Glacial Maximum (LGM). The ODP 658C record shows a “Green Sahara” interval from 60 to 50 ka during a time of high Northern Hemisphere summer insolation, with dust fluxes similar to levels during the early Holocene African Humid Period, and an abrupt peak in flux during Heinrich event 5a (H5a). Dust fluxes increase from 60 to 35 ka while the high-latitude Northern Hemisphere cools, with peaks in dust flux associated with North Atlantic cool events. From 35 ka through the LGM dust deposition decreases in all cores, and little response is observed to low-latitude insolation changes. Dust fluxes at sites north of 20°N were near late Holocene levels during the LGM time slice, suggesting a more muted LGM response than observed in mid-latitude dust sources. Records along the northwest African margin suggest important differences in wind responses during different stadials, with maximum dust flux anomalies centered south of 20°N during H1 and north of 20°N during the Younger Dryas.
Jan 2022Published in Paleoceanography and Paleoclimatology volume 37 issue 1. 10.1029/2020PA004137