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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 ...
Ultisol. 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 texture focuses on the particles that are less than two millimeters in diameter which include sand, silt, and clay. The USDA soil taxonomy and WRB soil classification systems use 12 textural classes whereas the UK-ADAS system uses 11. [1] These classifications are based on the percentages of sand, silt, and clay in the soil.
The PI is the difference between the liquid limit and the plastic limit (PI = LL-PL). Soils with a high PI tend to be clay, those with a lower PI tend to be silt, and those with a PI of 0 (non-plastic) tend to have little or no silt or clay. Soil descriptions based on PI: [8] (0) – Non-plastic (<7) – Slightly plastic (7-17) – Medium plastic
The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size of a soil. The classification system can be applied to most unconsolidated materials, and is represented by a two-letter symbol. Each letter is described below (with the exception of Pt): If the ...
Liquefaction is more likely to occur in sandy or non-plastic silty soils but may in rare cases occur in gravels and clays (see quick clay). A 'flow failure' may initiate if the strength of the soil is reduced below the stresses required to maintain the equilibrium of a slope or footing of a structure.