12 Facts About Chalk


Chalk is common throughout Western Europe, where deposits underlie parts of France, and steep cliffs are often seen where they meet the sea in places such as the Dover cliffs on the Kent coast of the English Channel.

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Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity.

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Chalk is a fine-textured, earthy type of limestone distinguished by its light color, softness, and high porosity.

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Chalk is highly porous, with typical values of porosity ranging from 35 to 47 per cent.

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Chalk was formed in the Cretaceous, between 99 and 65 million years ago.

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Chalk is the only form of limestone that commonly shows signs of compaction.

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Chalk is so common in Cretaceous marine beds that the Cretaceous Period was named for these deposits.

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Chalk Group is a European stratigraphic unit deposited during the late Cretaceous Period.

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Chalk deposits are found in Cretaceous beds on other continents, such as the Austin Chalk, Selma Group, and Niobrara Formations of the North American interior.

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Chalk is mined from chalk deposits both above ground and underground.

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Chalk mining boomed during the Industrial Revolution, due to the need for chalk products such as quicklime and bricks.

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Chalk is a source of quicklime by thermal decomposition, or slaked lime following quenching of quicklime with water.

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