Finding rates of incorporation of windblown dust into soils



As winds blow dust around, a significant amount settles back into terrestrial soils, providing minerals to the soils and affecting soil chemistry and erosion rates. However, the rate at which dust is incorporated into regolith, the loose soil and rock on surfaces, is difficult to measure, especially on eroding terrain. Ferrier et al. have developed a simple method of estimating the long-term (millennial-scale) rate of dust incorporation into actively eroding regolith by measuring regolith production rates and the concentrations of two immobile elements (e.g., zirconium and titanium) in dust, soil, and bedrock. The researchers applied their method at 17 field sites in the South Fork of the Salmon River in central Idaho and inferred dust incorporation rates of 3–13 tons per square kilometer per year, which is comparable to results from other studies. They suggest that their technique can be used to estimate long-term rates of dust incorporation into soils, which can then be compared to modern measurements of dust deposition to study the effects of recent changes such as climate change and human activity. (Journal of Geophysical Research-Earth Surface, doi:10.1029/2011JF001991, 2011)