Rocky Mountain Section - 68th Annual Meeting - 2016

Paper No. 7-2
Presentation Time: 8:00 AM-6:00 PM

USING THE CHEMICAL SIGNATURE OF DUST TO UNDERSTAND SOIL DEVELOPMENT AND CARBON STORAGE IN SOILS


TERHAAR, Danielle M., Geosciences, Boise State University, 1910 University Drive, Boise, ID 83725, danielleterhaar@u.boisestate.edu

Part of the reason Idaho is famous for potatoes is dust: long-term addition of dust creates rich, fertile soils. While fine air-borne silt provides nutrients and water-holding capacity important for crops, dust is also an important but understudied aspect of soil development. On a global scale, soils provide an important storage location for carbon, and provide a sink for atmospheric carbon dioxide. Plants, microbes, and microorganisms are responsible for organic carbon formation, but inorganic carbon requires the presence of mobile Ca+ ions to mix with water H2O and CO2 from the atmosphere to produce calcium carbonate CaCO3. Natural traps provide a unique opportunity to analyze the geochemistry of pure dust in the absence of pedogenesis, or soil-formation. We collected dust from natural basins in rhyolite, basalt and granite outcrops, and compared major element oxides and trace element geochemistry using Inductively Coupled Plasma Mass Spectrometery (ICPMS). This study (1) explores the chemical composition of pure dust as a primary soil forming material, (2) compares dust heterogeneity among different lithologies and throughout the watershed, and (3) constrains the origin of dust.