Eolian Processes and Sediments

Eolian processes, involving erosion, transportation, and deposition of sand, silt, and clay size sediment by the wind, occur in a variety of environments, including the coastal zone, semi-arid and arid regions (e.g., cold and hot deserts), and agricultural fields in many climates. Eolian processes are responsible for the production of a variety of erosional landforms that range in scale from individual rocks (ventifacts) to larger and more complex landforms—yardangs, inverted relief, and deflation basins. The wind is responsible for the emission and/or mobilization of dust (mineral aerosols of silt and clay size) and the transport of this material to distant marine and terrestrial areas, where it contributes significantly to soil formation and the nutrient status of a variety of ecosystems. Major depositional landforms comprise deposits of loess (silt) and areas of sand dunes (sand seas and dune fields). The morphology and sedimentary characteristics of modern and recent desert environments, together with an understanding of the mechanisms by which these systems accumulate and become preserved, provide the basis for the recognition and interpretation of ancient eolian successions, which form both outcropping examples, and which are known only from the subsurface. The stratigraphic architecture of ancient preserved desert sedimentary systems can be summarized in the form of a depositional or facies model.