The Spatial Distribution of Aeolian Dust and Terrigenous Fluxes in the Tropical Atlantic Ocean Since the Last Glacial Maximum

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Abstract
The flux of terrestrial material from the continents to the oceans links the lithosphere, hydrosphere, and biosphere through physical and biogeochemical processes, with important implications for Earth's climate. Quantitative estimates of terrigenous fluxes from sources such as rivers, aeolian dust, and resuspended shelf sediments are required to understand how the processes delivering terrigenous material respond to and are influenced by climate. We compile thorium‐230 normalized232Th flux records in the tropical Atlantic to provide an improved understanding of aeolian fluxes since the Last Glacial Maximum (LGM). By identifying and isolating sites dominated by aeolian terrigenous inputs, we show that there was a persistent meridional gradient in dust fluxes in the eastern equatorial Atlantic at the LGM, arguing against a large southward shift of the intertropical convergence zone during LGM boreal winter. The ratio of LGM to late‐Holocene232Th fluxes highlights a meridional difference in the magnitude of variations in dust deposition, with sites 700 km away, characterized by232Th fluxes approximately twice as large as aeolian‐dominated sites in the east.
Funding Information
  • Natural Environment Research Council (NE/L002434/1)
  • National Science Foundation

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