Session:  Mineralogy, geochemistry, and physical properties of atmospheric mineral dust: Influences on the atmosphere, the cryosphere, ecosystems, and humans (Topical Session 170)

Short Description: This session emphasizes the mineralogy, geochemistry, and physical properties of contemporary dust to understand the influences of atmospheric particulate matter on climate, weather, snow- and ice-melt, human health, landscape fertility, and ocean fertilization.   

Sponsors: Mineralogical Society of America, the Geochemical Society, GSA Divisions of Quaternary Geology and Geomorphology, Mineralogy, Geochemistry, Petrology, and Volcanology, and Geology and Health. 

Invited Speakers:

Dr. Andrew Ghio, MD, Clinical Research Branch, Environmental Public Health Division, US Environmental Protection Agency

Dr. Thomas Painter, Water and Carbon Cycles Group, Jet Propulsion Lab, Adjunct Professor of Geography UCLA

Dr. Andrew Roberts, Director of the Research School of Earth Sciences at the Australian National University

Convenors:

Richard Reynolds, United States Geological Survey

Suzzette Mormon, United States Geological Survey

Joshua Feinberg, Institute for Rock Magnetism, University of Minnesota

Rationale for session: 

Atmospheric particulate matter from dust storms is a major component of the Earth System with influences on climate, weather, melting of snow and ice, terrestrial ecosystem fertility, ocean fertilization, as well as on air quality and human health and safety.  Improved knowledge about the mineralogy, geochemistry, and physical properties of dust is urgently needed to understand better how contemporary dust affects many aspects of Earth environments and people.     

As one example, ferric oxide minerals are a common component in global atmospheric dust, and these minerals have radiative properties involving the absorption of solar radiation that (1) influence atmospheric circulation and climate by warming the atmosphere and (2) affect melting rates of snow and ice.  Specific iron oxide mineralogy and particle size are thought to be important factors for radiative effects but these factors are not well understood and are not fully incorporated into climate and snow-melt models.  Moreover, solubility of iron oxide minerals in dust is an important factor in phytoplankton fertilization, but more studies with natural dusts, representing the scope of global dust variability, are still desirable.  Dust mineralogy, furthermore, may affect functions of human organs, such as the lung, via reduction-oxidation reactions.  Dust composition plays important roles in ecosystem dynamics for several reasons, one of which is soil-nutrient uptake by plants.   

Despite the widespread importance of atmospheric dust, knowledge is lacking (a) about the connections among the mineralogy, geochemistry, and certain physical properties (e.g., particle-size distributions, solubility with respect to mineral type and size, reduction-oxidation potential, albedo) of dust and (b) about the linkages among these properties and climate, weather, snow- and ice-melt, human health, landscape fertility, and the oceanic biological pump.  This session will bring together researchers to build bridges among diverse disciplines in geology, geophysics (e.g., magnetic methods and reflection spectroscopy for iron-mineral studies), geochemistry, climate modeling, ecology, cryospheric studies, and human health and thereby to advance understanding of dust in Earth Systems. 

Dust storm Birdsville Australia, Jan. 2006, Karen Brooks