Dust proxies

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Dust proxies

• David McGee
• Elizabeth Pierce
• April 23, 2008

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Why study dust?

• Learn about sources
• Learn about transport
• Learn about impacts
• Radiative forcing (direct and indirect)
• Ocean chemistry (iron fertilization)
• Atmospheric chemistry

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Ice core dust studies

• Particle counting
• Soluble tracers (nssCa2)
• Insoluble tracers (Al, Fe)
• Estimating dust concentrations in air
• Greenland Concentrations may be more accurate
• Antarctica Fluxes may be more accurate

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Terrestrial dust studies

• Can indicate wind direction, wind intensity,
  source areas

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Ocean sediment dust studiesLeaching approach

• Use leaching procedures to remove
• Carbonate
• Opal
• Oxides/hydroxides
• Remaining material Operationally defined eolian
  dust

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Potential contaminants

• Volcanic ash
• Hemipelagic sediments
• IRD

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Results from dust-dominated areasNW African
coast
Adkins et al., 2006
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Results from dust-dominated areasNW African
coast
Adkins et al., 2006
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Results from dust-dominated areasNW Pacific
Rea, 1994 from Hovan et al., 1989
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Results from low-dust areasEquatorial Pacific

• Eastern EqPac (4N)

Central EqPac (0)
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Problems in low-dust areas

• gt50 of operationally defined eolian dust in
  EqPac cores is mafic volcanic material
  (La/Sc/Th analysis Olivarez, 1993)
• Problem applies as well to elements high in
  multiple detrital sources (e.g., Ti, Fe)

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Ocean dust fluxes from ODED approach