siltlike

Siltlike is a descriptive term used in geology and soil science to indicate a material whose grain-size distribution is dominated by silt-sized particles. Silt particles are typically in the range of about 2 to 63 micrometers in diameter, so a siltlike sediment consists mainly of grains within that size range, with smaller fractions of clay and/or very fine sand. The term is often used when a sample is not classified as pure silt, clay, or a loam but clearly resembles silt in texture and behavior.

Formation and occurrence: Siltlike deposits form in quiet-water settings where fine suspended sediments can settle out, such as river floodplains, lake bottoms, deltas, and glacial outwash plains. They accumulate where the supply of coarse sediment is limited and the flow velocity is low enough to permit silt deposition.

Properties: Siltlike materials are finer than sand but coarser than clay, giving them a smooth feel when dry and a cohesive, plastic consistency when wet. They typically have moderate to high porosity and moderate permeability relative to clay, and can retain substantial moisture. They are susceptible to erosion when dry or crusted, especially if vegetation is removed. In geotechnical terms, saturated siltlike soils can exhibit reduced shear strength and, under dynamic loading, may experience settlement or liquefaction depending on density and pore-water pressure.

Notes: Because siltlike is a descriptive designation rather than a formal soil class in all schemes, precise classification often requires particle-size analyses and consistency tests.

See also: silt, clay, loam, sedimentology, soil texture.