Columbia Plateau

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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 MonumentCraters of the Moon National Monument,
53,440 acres (21,636 hectares), S central Idaho; est. 1924. This region, composed of several closely grouped volcanoes, is suggestive of a telescopic view of the moon. Volcanic activity dating back c.
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) 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.

Columbia Plateau


a lava plateau in the North American Cordillera. Located in the northwestern USA, between the Cascades to the west and the Rockies to the east. Area, approximately 500,000 sq km; elevation, 700–1,000 m.

The foundation is composed of Paleozoic and Mesozoic crystalline and sedimentary rock, covered on the surface with Miocene and Pliocene basalt; the plateau’s surface is flat or undulating and covered with loess; in the north it is morainic and dissected by the canyons of the Columbia, Snake, and other rivers with depths to 900 m (on the Columbia River) and 1,500 m (on the Snake River). There are also dry canyons, formed in Anthropogenic times (the largest is the Grand Coulee). The rivers have many waterfalls and rapids, and hydroelectric power plants have been constructed. Most of the plateau is covered with turf and grass steppes, now tilled. Wheat is the main crop.

References in periodicals archive ?
"In common with other Indian Nations of America they extract their beard," noted William Clark in his journals as he and the Corps of Discovery encountered the Columbia Plateau Natives.
The northeastern portion of Oregon where genetic samples were collected included 3 ecoregions: the Blue Mountains, Columbia Plateau, and Snake River Plain (USEPA 2003; Fig.
The area includes the best, most diverse montane grasslands remaining in the Columbia Plateau, as well as other notable mountain habitats.
During the 20th century, the four elders of the Snake River-Palouse lived free and open lives on the Columbia Plateau traveling on their seasonal round of root grounds, fishing areas, and hunting landscapes.
Gollany works at the ARS Columbia Plateau Conservation Research Center in Pendleton, Oregon, while Young works at the ARS Land Management and Water Conservation Research Unit in Pullman, Washington.
Our half of the state is mainly the Columbia Plateau, slightly depressed basalt formation--a large igneous province, officially--marked with valleys formed by prehistoric lake beds.
Songs of power and prayer in the Columbia Plateau; the Jesuit, the medicine man, and the Indian hymn singer.
Other geographic elements of the Pacific Northwest include the Columbia Plateau, a high area of land that stretches east to the Rocky Mountains in Idaho and Montana.
The Wenatchi and Other Tribes of the Columbia Plateau Prior to
Spread across the states of Washington, Oregon and Idaho, the Columbia Plateau was formed by the Grande Ronde lava flows, which produced enough molten basalt to sink the Earth's crust.
The value-added marketing business they formed, Columbia Plateau Producers LLC, today has 32 member-farmers and sells high-quality flour under the Shepherd's Grain brand to bakeries from Seattle to Northern California.

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