oolite

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Related to oolitic: Oolitic limestone

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.

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

oolite

[′ō·ə‚līt]
(petrology)
A sedimentary rock, usually a limestone, composed principally of cemented ooliths. Also known as eggstone; roestone.

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.

oolite

any sedimentary rock, esp limestone, consisting of tiny spherical concentric grains within a fine matrix
References in periodicals archive ?
Analyses of microscopic structures and penetrative finite strain direction in the oolitic limestone of the Ambar Formation accommodated shortening parallel to the trend of the Swabi Synclinorium and Shewa Anticlinorium.
Name 1 Carbuncle 2 K feldspar 3 Albite 4 Tektite 5 Magnetite 6 Demantoid 7 Oolitic hematite 8 Pink pyroxene 9 Idocrase 10 Black hematite 11 Biotite 12 Hornblende 13 Calcite 14 Labradorite 15 Magnesite 16 Rhodonite 17 Reniform hematite 18 Banded siliceous rocks 19 Diopside 20 Selenite 21 Alabaster 22 Anhydrite 23 Moonstone 24 Barite 25 Hypersthene Table 2: Emission lines for classification based on major elements from geological samples.
The corresponding SEM images (Figure 4) confirmed that the hematite ore consisted mainly of scaly, acicular, cryptocrystalline, and metasomatic textures, with a sand consolidation structure (rarely, with an oolitic structure).
From the oldest to youngest the strata include (Poldsaar & Ainsaar 2014): (i) glauconitic sandstones and limestones of the Toila Formation (Billingen and Volkhov regional stages), (ii) interbedded sandy limestones of the Pakri Formation (Kunda Regional Stage), (iii) a distinct iron oolitic limestone bed of the Kandle Formation (Aseri Regional Stage) and (iv) relatively thick-bedded and hard bioclastic limestones of the Vao Formation (Lasnamagi and Uhaku regional stages).
* The discovery of a large formation of oolitic limestone in Indiana leads to huge industry growth there.
Extensive banks of oolitic sand, seagrass meadows, mangroves, and tidal creeks provide nursery areas and feeding grounds for sharks, conch, sea cucumbers, spiny lobsters, and marine turtles.
The shallow oolitic limestone platform that makes up the Caicos Banks is an ideal habitat for these organisms.
These sediments show lateral and vertical transition to shallow marine sandstone, conglomerate, shale, marl and oolitic limestones [2].
29,500 BCE At the heart of the collection of the Naturhistorisches Museum in Vienna is one of the most famous Paleolithic representations of the body--a four-inch-tall oolitic limestone carving that is controversially referred to as Venus.
Helmut Pristacz (University of Vienna, Austria, and University of Tokyo, Japan) and coauthors studied synthetic turquoise from the Natural History Museum in Vienna, Austria, and found that it had an oolitic microstructure composed of a fibrous amorphous phase (related to the high-pressure berlinite structure) together with natural turquoise (presumably used as a starting material) and synthetic turquoise.
The centipedes were observed under various natural cover objects (e.g., fallen logs and oolitic limestone boulders) and discarded materials (e.g., plywood and carpet), many of which housed multiple (from 3 to 6) specimens.