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boulder

The Columbia Encyclopedia, 6th ed. | 2011 | Copyright

boulder large rock fragment formed by detachment from its parent consolidated rock by weathering and erosion. In engineering and geology, especially in the United States, the term is applied to loose rocks having specific sizes according to various systems of classification, i.e. the Wentworth scale (for C. K. Wentworth, American geologist), where a boulder has one linear dimension of at least 10.1 in. (25.4 cm). Boulders transported by glacial ice are usually referred to as glacial erratics; glacial boulder fields, or felsenmeer, containing large blocks of angular rock broken from intense frost action are evidence that the region has experienced glacial action in the past. See drift ; moraine .

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boulder

The Oxford Pocket Dictionary of Current English | 2009 | Copyright

boul·der / ˈbōldər/ (also bowl·der) • n. a large rock, typically one that has been worn smooth by erosion. DERIVATIVES: boul·der·y adj.

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boulder

A Dictionary of Earth Sciences | 1999 | | Copyright

boulder See PARTICLE SIZE.

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AILSA ALLABY and MICHAEL ALLABY. "boulder." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>.

AILSA ALLABY and MICHAEL ALLABY. "boulder." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O13-boulder.html

AILSA ALLABY and MICHAEL ALLABY. "boulder." A Dictionary of Earth Sciences. 1999. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-boulder.html

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