concretion

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concretion

concretion mass or nodule of mineral matter, usually oval or nearly spherical in shape, and occurring in sedimentary rock. It is formed by the accumulation of mineral matter in the pore spaces of the sediment, usually around a fossil or fossil fragment acting as a nucleus. Most concretions are very dense and compact, and are usually composed of calcite, silica, or iron oxide. The material making up the concretion is believed to come from the surrounding rock, being redeposited around the nucleus. Concretions range in diameter from a fraction of an inch to many feet, although most are but a few inches in diameter. Perhaps the best known are the flint nodules found in chalk deposits such as those at Dover, England. Concretions having radiating cracks filled with mineral matter are called turtle stones, or septaria.

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concretion

A Dictionary of Ecology | 2004 | | Â© A Dictionary of Ecology 2004, originally published by Oxford University Press 2004. (Hide copyright information) Copyright

concretion A localized concentration of material (e.g. calcium carbonate or iron oxide) in the form of a nodule of varying size, shape, or colour.

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MICHAEL ALLABY. "concretion." A Dictionary of Ecology. 2004. Encyclopedia.com. 17 Dec. 2009 <http://www.encyclopedia.com>.

MICHAEL ALLABY. "concretion." A Dictionary of Ecology. 2004. Encyclopedia.com. (December 17, 2009). http://www.encyclopedia.com/doc/1O14-concretion.html

MICHAEL ALLABY. "concretion." A Dictionary of Ecology. 2004. Retrieved December 17, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-concretion.html

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concretion

A Dictionary of Plant Sciences | 1998 | | Â© A Dictionary of Plant Sciences 1998, originally published by Oxford University Press 1998. (Hide copyright information) Copyright

concretion A localized concentration of material (e.g. calcium carbonate or iron oxide) in the form of a nodule of varying size, shape, or colour.

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MICHAEL ALLABY. "concretion." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. 17 Dec. 2009 <http://www.encyclopedia.com>.

MICHAEL ALLABY. "concretion." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. (December 17, 2009). http://www.encyclopedia.com/doc/1O7-concretion.html

MICHAEL ALLABY. "concretion." A Dictionary of Plant Sciences. 1998. Retrieved December 17, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O7-concretion.html

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	Carbonate Concretions Part 2.(Brief Article)(Statistical Data Included) Magazine article from: Rocks & Minerals; 9/1/1999
	Carbonate Concretions Part 1. Magazine article from: Rocks & Minerals; 7/1/1999
	Ohio mineral locality index: part 2: concretions and miscellaneous occurrences. Magazine article from: Rocks & Minerals; 9/1/2002

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