Late Quaternary eolian dust in surficial deposits of a Colorado Plateau grassland: Controls on distribution and ecologic effects

摘要: Abstract In a semi-arid, upland setting on the Colorado Plateau that is underlain by nutrient-poor Paleozoic eolian sandstone, alternating episodes of dune activity and soil formation during late Pleistocene Holocene have produced dominantly sandy deposits support grass shrub communities. These also contain dust, especially in paleosols. Eolian dust these indicated several mineralogic chemical disparities with local bedrock, but it most readily shown abundance titaniferous magnetite absent bedrock. Magnetite some potential plant nutrients (especially, P, K, Na, Mn, Zn) covary positively depth (3–4 m) dune-crest dune-swale settings. correlates strongly abundances other elements (e.g., Ti, Li, As, Th, La, Sc) are geochemically stable environments. Soil-property variations can be ascribed to three primary factors: (1) shifts geomorphic setting; (2) accumulation relatively high amounts atmospheric mineral inputs periods land-surface stability; (3) flux composition likely related changes dust-source regions. Shifts revealed large texture expressed magnetic properties. Variable both relations among magnetic, chemical, textural The largest found sediment spans early time. Increased central this period may been desiccation shrinkage lakes from about 12 8 ka western North America exposed vast surfaces capable emitting dust. Soil properties result variable redistribution surficial Quaternary important modern ecosystem dynamics because plants today utilize deposited as long ago 12–15 ky fine-grained (silt) sediment, including influence soil-moisture capacity.