oolite (ōˈəlīt, ōˈō–), rock composed of small concretions, usually of calcium carbonate, containing a nucleus and clearly defined concentric shells. In the British Isles oolitic limestone is characteristic of the middle and upper Jurassic, which was formerly termed the Oolite on this account.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
(according to some sources, oolith), a spheroidal or ellipsoidal formation consisting of oxides and silicates of iron and manganese and of calcite, dolomite, aragonite, rhodochro-site, leptochlorite, and other minerals. Oolites range in size from several microns to 15–25 mm. Oolites larger than 2–5 mm are called pisolites. In the center of an oolite there is usually—but not always—a grain of sand or a fragment of the calcareous shell of some organism, around which thin layers of the precipitating substance accrete; as a result the structure of oolites is usually concentric-botryoidal. Oolites with radial and complex structures (combinations of concentric-botryoidal and radial structures) are also found. Oolites form in seawater and warm springs as a result of colloid-chemical and biochemical processes. Ferruginous oolites are a variety of iron ore.
REFERENCEShvetsov, M. S. Petrografiia osadochnykh porod, 3rd ed. Moscow, 1958.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
A sedimentary rock, usually a limestone, composed principally of cemented ooliths. Also known as eggstone; roestone.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
A granular limestone, each grain of which is more or less spherical and made up of concentric coats of carbonate of lime formed around a nucleus.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
any sedimentary rock, esp limestone, consisting of tiny spherical concentric grains within a fine matrix
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005