The Influence of Eolian Dust on the Genesis of Alpine Soils in the Front Range, Colorado

Abstract

The chemical and mineralogical properties of the soils in an alpine watershed, Front Range, CO, were studied to assess the sensitivity of the soil environment to acid deposition. Field and laboratory analyses indicated that properties of surface horizons were heavily influenced by eolian dust accumulation whereas the subsurface horizons were mainly derived from local bedrock. Surface and subsurface horizons differed in texture, bulk density, pH, CEC, exchangeable cations, and clay and silt mineralogy. A discriminant analysis based on these parameters proved useful for confirming lithologic differences between the surface (alpine loess) and subsurface horizons (bedrock residua). The alpine environment in the Front Range, which is naturally acidic and therefore very susceptible to acid deposition, has been affected by wind‐blown calcite that has raised the pH of surface horizons. Such natural liming presumably increases the ability of the alpine soils to buffer acid deposition.