Concretion

Rock City, near Minneapolis

Description

In geology, concretion is an anomalous mass of mineral matter found in Sandstone, Clay, or other Sedimentary rock. Concretions are form by the deposition of Silica, Calcite, Gypsum, or other chemical compound. They are often found in concentric layers surrounding an original nucleus.

Sandstone concretion

Concretions
Credit: J. Delgado Rodrigues

Synonyms and Related Terms

agglomerate; concrétion (Fr.);concrecion (Esp.); concreção (Port.); Konkretion (Deut.); concretie (Ned.)

Additional Images

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  'Devil's Bake Oven' at Mushroom Rock State Park

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  'Pulpit Rock' at Mushroom Rock State Park

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  Dakota Sandstone concretion

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  Dakota Formation sandstone concretions

Resources and Citations

• ICOMOS-ISCS: Illustrated glossary on stone deterioration patterns

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971

• Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998