Coquina

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coquina

[kō′kē·nə]
(invertebrate zoology)
A small marine clam of the genus Donax.
(petrology)
A coarse-grained, porous, easily crumbled variety of limestone composed principally of mollusk shell and coral fragments cemented together as rock.

Coquina

 

limestone consisting primarily of the shells of marine animals or fragments of shells. Coquina usually forms in the littoral or sublittoral zones. Depending on the shells of which it is composed, coquina is subdivided into brachiopod, gastropod, ostracod, and other types. It corresponds to gravelpebble sediments in granulometric composition. Coquina has a very high porosity of 22–60 percent. Its specific gravity is 1,100-2,240 kg/m3, and its heat conductivity coefficient is 0.29-0.99 watt/(m-°K), or 0.25-0.85 kcal/(hr-m-°C). Its breaking point upon compression is 0.4-28 MN/m2 (4-280 kg/cm2).

Coquina is easily sawed, trimmed, and worked in various other ways. It is used extensively in construction as a wall and facing material; chipped rock and sand from coquina are used as a filler for light concrete. In addition, coquina is used in the production of lime and other binding materials. It is extracted in quarries.

Coquina is widespread in the Neogene beds of the southern USSR: in the Moldavian SSR, in the Crimean (the Mamai, Kutur-Kaia, Bagerovo, and Karalar deposits) and Odessa oblasts of the Ukrainian SSR, in the Azerbaijan SSR (the Apsheron Peninsula), and in the Turkmen SSR. Abroad, coquina is found in Poland and Rumania.

coquina

A soft limestone formed primarily of broken shells and coral; cut into blocks and used in construction.
References in periodicals archive ?
The population ecology and reproductive biology of coquina clams (Donax variabilis) on a Florida beach.
The coquina clam ranges along the Atlantic coast of the United States from Virginia to Florida and as far west in the Gulf of Mexico as Texas (Morrison 1971).
A comparison of two Florida populations of the coquina clam, Donax variabilis Say, 1822 (Bivalvia: Donacidae) 1.
Coquina clams, Donax denticulatus, called almejas (Spanish) or ahis (Miskito) locally, are numerous in the surf zone along Caribbean beaches of Honduras.
2310[degrees]), north of the Matanzas Inlet, in the same vicinity and water depths where indigenous people could have harvested coquina clams thousands of years ago (see Fig.
Seasonal collection of coquina clams (Donax variabilis Say, 1822) during the Archaic and St.
ABSTRACT The variable coquina clam, Donax variabilis, is one of the most common inhabitants of exposed sandy beach intertidal and shallow subtidal zones in the southeastern United States.
The variable coquina clam, Donax variabilis Say, 1822, is one of the most common, recognizable bivalve mollusks from sandy beach habitats of the southeastern United States.