Eolian

Summary

An Eolian environment (also spelled Aeolian) is a depositional environment in which the driving force of sediment movement, erosion, and deposition is wind. Since these eolian processes are  driven by the movement of wind, they are heavily dependent on the interactions and changes of both atmospheric and surface conditions (Zhu et al., 2014).  Due to the lower viscosity of air compared to water, fluid flow in eolian environments is turbulent, not laminar. There are 3 primary modes of particle transport in Eolian processes; creep, saltation, and suspension. The creep process involves particles with sizes greater than 500um. It is simply the rolling movement of the sediment across the floor of the sedimentary bed. Saltation describes particles being temporarily picked up by wind and "jumping" short distances, it involves particles between 20-500um. Both creep and saltation processes only move particles between a couple meters to a couple hundred meters. Suspension describes the process of particles being lifted up and suspended by winds. Suspension will only involve particles that are less than 20um in size (Wang et al., 2015). Depending on wind conditions, these suspended particles can be transported across vast distances. A varying combination of these processes will make a number of different sedimentary structures. Dunes and antidunes are key structures in an eoilan environments, as well as ripples and planar bedding (Boggs, 2014). 

While there are different types of Eolian systems, they most typically consist of arid desert environments. Deserts are environments in which the potential evaporation rates greatly outweigh potential rainfall, commonly receiving only ~25cm per year. While deserts are typically thought of as being hot environments, they include cold arid environments as well. Deserts can be found on every major continent, including Antarctica (Okin et al., 2005). While deserts can consist of many different subenvironments, there are 2 main types that make up most modern deserts, dune fields and ergs. Ergs, also called "Sand Seas", are large sections of desert (125km2) covered with windblown sands. Dune fields are smaller sections of desert populated by sandy dunes. Together, these 2 subenvironments make up ~20% of all desert environments, with the remaining portions made up of desert flats, rocky outcrops, and eroding mountains (Boggs, 2014).