caliche
caliche
A term applied broadly in the Southwestern United States (esp. Arizona) to a reddish-brown to buff or 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 is composed largely of crusts of soluble calcium salts in addition to such materials as gravel, sand, silt, and clay. It is called hardpan, calcareous duricrust, or calcrete in some localities, and kankar in parts of India.; tepetate. ---Etymol: American Spanish, from a Spanish word for almost any porous material (such as gravel) cemented by calcium carbonate.
Gravel, rock, soil, or alluvium cemented with soluble salts of sodium in the nitrate deposits of the Atacama Desert of northern Chile and Peru; it contains sodium nitrate (14% to 25%), potassium nitrate (2% to 3%), sodium iodate (up to 1%) sodium chloride, sodium sulfate, and sodium borate, mixed with brecciated clayey and sandy material in beds up to 2 m thick.
A term used in various geographic areas for a thin layer of clayey soil capping a gold vein (Peru); whitish clay in the selvage of veins (Chile); feldspar, white clay, or a compact transition limestone (Mexico); a mineral vein recently discovered, or a bank composed of clay, sand, and gravel in placer mining (Colombia). The term has been extended by some authors to quartzite and kaolinite.
Time in Riyadh 
at any time
