LOESS

Loess, transported and deposited by wind, is the soil material finer than sands and covering land areas. A loess can cover land surface from a few meters to several hundred meters. Loess is characterized by a neutral pH, and well-balanced clay and organic matter.
Loess soils are a type of aeolian soils. Loess soils are unconsolidated, unstratified, calcareous and rich in plant nutrients. They are productive and have unusual properties, in that they (a) are open and porous, (b) have vertical cuts making them fairly stable, and (c) can prevent problems like the formation of sinkholes, cavities and subsurface channel cutting, when used for earthen dams.
Its main components are quartz, feldspar, calcite and clay mineral. There are large areas covered by loess soils in the USA, China, Germany and Argentina.