Caliche

Mostly used for a reddish brown to white calcareous material of secondary accumulation, commonly found in layers on or near the surface of stony soils of arid and semiarid regions, but also occurring as a subsoil deposit in subhumid climates. It may occur as a thin, friable horizon within the soil, but more commonly it is up to a metre or more in thickness, impermeable and strongly indurated. It is composed largely of a calcareous cement, in addition to such materials as gravel, sand and mud. Roughly equivalent to calcrete.

A name of spanish language origin that means different things in different places. In Chile it is used for the nitrate bed ores (principally but not exclusively nitratine). Andean sulphur miners sometimes use it for white sulphate crusts created by acid fumarolic alteration of volcanic rocks. In the American Southwest this name is also commonly used to refer to crusts of carbonate (calcite) recently deposited on rocks and in seams, and as a term for soils in semi-arid areas that have become indurated by interstitial carbonate deposition.