|1.||Also called: calcrete a bed of sand or clay in arid regions cemented by calcium carbonate, sodium chloride, and other soluble minerals|
|2.||Also called: duricrust a surface layer of soil encrusted with calcium carbonate, occurring in arid regions|
|[C20: from American Spanish, from Latin calx lime]|
calcium-richcalcium-rich duricrust, a hardened layer in or on a soil. It is formed on calcareous materials as a result of climatic fluctuations in arid and semiarid regions. Calcite is dissolved in groundwater and, under drying conditions, is precipitated as the water evaporates at the surface. Rainwater saturated with carbon dioxide acts as an acid and also dissolves calcite and then redeposits it as a precipitate on the surfaces of the soil particles; as the interstitial soil spaces are filled, an impermeable crust is formed.
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