Loess

:This article is about the geologic material, for the statistical technique see Loess curve.

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Among the classifications of soil types, loess (pronounced l?s, from the German L??, and ultimately from Swiss German l?sch, loose) is a fine, silty, windblown (eolian) type of unconsolidated deposit, or, sometimes the term refers to the soil derived from it. It is derived from glacial deposits, where glacial activity has ground rocks very fine (rock flour). After drying, these deposits are highly susceptible to wind erosion, and downwind deposits may become very deep, even hundreds of feet, as in areas of China and the midwestern United States.

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Hungary has several areas that are covered by loess. At locations such as Duna?jv?ros and Balatonakarattya, loess walls are exposed as "reefs" (see illustration).

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The central part of Belgium is also covered by thick loess stacks. An interesting loess site where late Middle and Late Pleistocene Neanderthal artefacts were found within the soils between the loess layers is Veldwezelt-Hezerwater.

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Loess grains are angular, with little polishing or rounding, composed of crystals of quartz, feldspar, mica and other minerals. Because the grains are angular, loess will often stand in banks for many years without slumping. This soil has the characteristic called vertical cleavage, which makes it easily excavated to form cave dwellings; this is still a popular method of making human habitations in some parts of China. But it is also highly erodible by water or wind, and soils underlain by loess tend to be excessively drained (droughty). As the grains weather, they release minerals which means that soils derived from loess are usually very rich.

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German: German may mean:...

Swiss German: Swiss German (Schweizerdeutsch, Schwyzerd?tsch, Schwiizerd?tsch, Schwyzert?tsch, Schwizertitsch) is any of the Alemannic dialects spoken in Switzerland. Occasionally, the Alemannic dialects spoken in other countries are called Swiss German as well, especially the dialects of Liechtenstein which are ...