Duricrusta

Duricrusta is a term used in geology and soil science to describe a hardened crust that forms at or near the surface of soils and regolith through cementation of mineral constituents. It is often considered part of the broader concept of a duricrust, which encompasses any hard, cemented layer created within the soil profile by mineral precipitation and sediment binding.

Formation occurs when dissolved minerals in groundwater precipitate and bind soil particles together. Cementing agents commonly include calcium carbonate, iron oxides or hydroxides, silica, and clays. Processes such as evaporation, seasonal wetting and drying, and chemical weathering drive mineral concentrations that lead to precipitation and hardening. Biological activity can also influence cementation by concentrating certain ions or promoting mineral precipitation on root surfaces and soil aggregates.

Duricrusts are typically categorized by their dominant cementing mineral. Calcrete or caliche is carbonate-rich and forms in arid to semi-arid regions. Ferricrete is iron-oxide-rich and common in tropical or subtropical settings with intense weathering. Silcrete is cemented by silica and can occur in various climates. Other forms include hardpans and various mixed or intermediate duricrusts, where multiple cementing minerals contribute to the hardness.

Distribution and environment vary, but duricrusts are most common in climates with limited rainfall but substantial groundwater movement, such as arid, semi-arid, and some tropical regions. They influence soil permeability, root penetration, water storage, and land-use potential, and they can pose challenges for construction, agriculture, and groundwater management.

See also: calcrete, ferricrete, silcrete, hardpan, duricrust.