oolite


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oolite

(ō`əlīt, ō`ō–), 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 It might be outdated or ideologically biased.

Oolite

 

(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.

REFERENCE

Shvetsov, M. S. Petrografiia osadochnykh porod, 3rd ed. Moscow, 1958.

V. A. GROSSGEIM

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

oolite

[′ō·ə‚līt]
(petrology)
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.

oolite

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.

oolite

any sedimentary rock, esp limestone, consisting of tiny spherical concentric grains within a fine matrix
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
It has a deeper Minagish Oolite Fm producing heavy oil, and a Lower Jurassic Marrat Fm with large reserves of light oil.
United States Department of State and Government of Pakistan project report, 43, 92.Donahue, J., 1969.Genesis of oolite and pisolite grains.
The Agbaja Formation and the iron mineralisation is laterally and aerially extensive across the Agbaja Plateau and consists of an upper unit comprising beds of ferruginous sandstone and reworked oolite/pisolite material (referred to as the Laterite unit) that overlies a sequence of massive ferruginous oolite and pisolite in a ferruginous matrix.
"The upper Jurassic Smackover formation is part of a zone up there called Reynolds oolite. Historically, there's been a lot of production at the upper Smackover."
Each cycle began with deposition of carbonate pelletal mud, micrite, followed upward by fossiliferous calcarenties and an upward shoaling oolite bar.
This oolite material can be used in vinyl, polyester, and urethanes, minimizing mold wear.
Geologically, it is in the wrong county, the proof being the golden acres of Inferior Oolite - or honey Cotswold stone - but there is nothing inferior about Broadway or its prized position at the foot of the Cotswold hills.
He did not like this vision, and yet, a child of his time, found it compelling, somehow guaranteed to be significant, as a geological survey of oolite would not be.
Figure 3 illustrates this phenomenon and the controlling factors for the well-studied Cenozoic limestones and dolostones from Florida and the Jurassic Smackover oolite reservoirs in the southern United States.