Cutans are the modification of the soil texture

Soil texture

Soil texture is a qualitative classification tool used in both the field and laboratory to determine classes for agricultural soils based on their physical texture. The classes are distinguished in the field by the 'textural feel' which can be further clarified by separating the relative...

, or soil structure

Soil structure

Soil structure is determined by how individual soil granules clump or bind together and aggregate, and therefore, the arrangement of soil pores between them...

, at natural surfaces (particle, pore, or ped) in soil materials due to illuviation

Illuvium

Illuvium is material displaced across a soil profile, from one layer to another one, by the action of rainwater. The removal of material from a soil layer is called eluviation. The transport of the material may be either mechanical or chemical. The process of deposition of illuvium is termed...

. Cutans are oriented deposits which can be composed of any of the component substances of the soil material. Cutans are common features in soil and represent focuses of chemical and biological reactions. Cutans may include clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 skins or coatings of silica, sesquioxide

Sesquioxide

A sesquioxide is an oxide containing three atoms of oxygen with two atoms of another element. For example, aluminium oxide is a sesquioxide.Many sesquioxides contain the metal in the +3 oxidation state and the oxide ion, e.g., Al2O3, La2O3...

, manganese

Manganese

Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...

, ferromanganese

Ferromanganese

Ferromanganese, a ferroalloy with high content of manganese, is made by heating a mixture of the oxides MnO2 and Fe2O3, with carbon, usually as coal and coke, in either a blast furnace or an electric arc furnace-type system, called a submerged arc furnace. The oxides undergo carbothermal reduction...

, soil organic matter

Soil organic matter

Organic matter is matter that has come from a once-living organism; is capable of decay, or the product of decay; or is composed of organic compounds...

 or carbonate

Carbonate

In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....

. Clay skins are also called argillans, and soil horizons with sufficient clay illuviation are termed argillic horizons.

Significance

Cutans provide physical evidence, observable in the field, as to the degree and nature of pedogenesis

Pedogenesis

Pedogenesis is the science and study of the processes that lead to the formation of soil ' and first explored by the Russian geologist Vasily Dokuchaev , the so called grandfather of soil science, who determined that soil formed over time as a consequence of...

. The ability to assess cutans is a core skill in soil morphology

Soil morphology

Soil morphology is the field observable attributes of the soil within the various soil horizons and the description of the kind and arrangement of the horizons. C.F...

 and paleopedology

Paleopedology

Paleopedology is the discipline that studies soils of past geological eras, from quite recent to the earliest periods of the Earth's history...

.