| Share
 

Columbia Plateau

Columbia Plateau, physiographic region of North America, c.100,000 sq mi (259,000 sq km), NW United States, between the Rocky Mts. and the Cascade Range in Washington, Oregon, and Idaho. Most of the plateau is underlaid by deposits, more than 10,000 ft (3,048 m) thick in places, of lava (mainly basalt) interbedded with sedimentary rock; older rocks outcrop in the Blue and Wallowa mts. Young lavas, scattered cinder cones, volcanic ash, and barren landscapes (including Craters of the Moon National Monument) are features of the Snake River plain in the south. Older, decayed lavas, much modified by accumulations of loess, occur in the north in the Columbia basin section; coulees (dry river canyons) and scablands (extensively eroded basalt surfaces), both carved by glacial meltwaters, are features of the region. The Columbia Plateau is an important agricultural and grazing area and is a major source of hydroelectric power.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on Columbia Plateau from Infoplease:

  • Blue Mountains, United States - Blue Mountains Blue Mountains, uplifted, eroded part of the Columbia Plateau, c.6,500 ft (1,980 m) ...
  • Great Basin - Great Basin Great Basin, semiarid, N section of the Basin and Range province, the intermontane ...
  • plateau - plateau plateau, elevated, level or nearly level portion of the earth's surface, larger in ...
  • Columbia, river, Canada and the United States - Columbia Columbia, river, c.1,210 mi (1,950 km) long, rising in Columbia Lake, SE British Columbia, ...
  • loess - loess loess , unstratified soil deposit of varying thickness, usually yellowish and composed of ...

See more Encyclopedia articles on: U.S. Physical Geography


Premium Partner Content
HighBeam Research
Documents Images and Maps Reference
(from Newspapers, Magazines, Journals, Newswires, Transcripts and Books)

Research our extensive archive of more than 80 million articles from 6,500 publications.

Additional search results provided by HighBeam Research, LLC. © Copyright 2005. All rights reserved.

24 X 7

Private Tutor

Click Here for Details
24 x 7 Tutor Availability
Unlimited Online Tutoring
1-on-1 Tutoring