Eolian Environment

Eolian (or aeolian) sediments are wind deposited materials that consist primarily of sand or silt-sized particles. These materials tend to be extremely well sorted and free of coarse fragments. Some rounding and frosting of mineral grains is detectable.

Loess

The term loess (meaning “crumbly” in German) is used to describe silt textured eolian material. Loess can be interpreted as an accumulation of wind-blown dust, usually of glacial origin. Typically it has no horizontal stratification, but occurs in a single massive layer. A large proportion of the material may consist of fresh, sharp-cornered particles of silicate minerals such as feldspars, quartz, and mica that make it light brown or yellow in color. Loess has a small amount of clay, so it is not sticky but rather slippery sediment. A very high angle of repose of this sediment allows it to erode into very steep slopes or cliffs.

The central and northwestern areas of the United States, Ukraine, eastern China, and eastern and central Europe all have significant deposits of loess. Agriculture has thrived in these areas since prehistoric humans took advantage of the rich soil to grow crops.

The central and northwestern areas of the United States, Ukraine, eastern China, and eastern and central Europe all have significant deposits of loess. Agriculture has thrived in these areas since prehistoric humans took advantage of the rich soil to grow crops.

Volcanic Tephra

Volcanic tephra is a term covering all volcanic ejecta. Most common volcanic parent material is volcanic ash, which is the material produced by volcanic eruptions that is carried by wind for very great distances. It consists of sand and silt size particles and it tends to diminish in thickness and particle size downwind from the source.

Eolian Sand

Sand wind-blown debris often accumulates to form rounded hillocks known as dunes. Originally the growth of dune is started by an obstacle, such as a stone, a brush, or an irregularity in the surface of the ground, which breaks the force of the wind. After the resulting heap of sand has grown to appreciable size it acts as its own wind-break and causes further deposition.

Eolian Parent Material

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