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A Quaternary clay deposit in Estonia, laid down about 400,000 years ago. Clay is a type of fine-grained natural soil material containing clay minerals [ 1 ] (hydrous aluminium phyllosilicates, e.g. kaolinite, Al 2 Si 2 O 5 (OH) 4). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities ...
Clay cannot be resolved by optical microscopes as its particles are 0.002 mm (7.9 × 10 −5 in) or less in diameter and a thickness of only 10 angstroms (10 −10 m). [16] [17] In medium-textured soils, clay is often washed downward through the soil profile (a process called eluviation) and accumulates in the subsoil (a process called ...
Soil deposits are affected by the mechanism of transport and deposition to their location. Soils that are not transported are called residual soils—they exist at the same location as the rock from which they were generated. Decomposed granite is a common example of a residual soil. The common mechanisms of transport are the actions of gravity ...
Claypan is a dense, compact, slowly permeable layer in the subsoil. [1] It has a much higher clay content than the overlying material, from which it is separated by a sharply defined boundary. The dense structure restricts root growth and water infiltration. Therefore, a perched water table might form on top of the claypan. [2]
Ultisol, commonly known as red clay soil, is one of twelve soil orders in the United States Department of Agriculture soil taxonomy. The word "Ultisol" is derived from "ultimate", because Ultisols were seen as the ultimate product of continuous weathering of minerals in a humid, temperate climate without new soil formation via glaciation .
Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from soil by restricting the former term specifically to displaced soil.
Soil types by clay, silt and sand composition as used by the United States Department of Agriculture. Loam (in geology and soil science) is soil composed mostly of sand (particle size > 63 micrometres (0.0025 in)), silt (particle size > 2 micrometres (7.9 × 10 −5 in)), and a smaller amount of clay (particle size < 2 micrometres (7.9 × 10 −5 in)).
Expansive clay is a clay soil that is prone to large volume changes (swelling and shrinking) that are directly related to changes in water content. [1] Soils with a high content of expansive minerals can form deep cracks in drier seasons or years; such soils are called vertisols. Soils with smectite clay minerals, including montmorillonite and ...