boulder (redirected from Boulder (geology))

Boulder, city, United States

Boulder, city (1990 pop. 83,312), seat of Boulder co., N central Colo.; inc. 1871. A Rocky Mountain resort and a suburb of Denver, it is the seat of the Univ. of Colorado (1876). Industries include aerospace and biological research and the manufacture of machinery; electric, electronic, and computer equipment; and medical supplies. Boulder is home to the National Center for Atmospheric Research and other government and private research operations and is known as a mountain sports and "New Age" mecca.

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boulder, in geology

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

City (pop., 2000: 94,673), north-central Colorado, U.S. Located at the base of the Rocky Mountains northwest of Denver, it was settled by miners in 1858 and grew with the arrival of two railroads in 1873. An extensive government-industrial-educational complex has developed since the 1950s. It is the site of the University of Colorado.

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boulder

1. a smooth rounded mass of rock that has a diameter greater than 25cm and that has been shaped by erosion and transported by ice or water from its original position

2. Geology a rock fragment with a diameter greater than 256 mm and thus bigger than a cobble