Sources
Help build the largest human-edited directory on the web.
Submit a site - Become an editor
Wikipedia. Licensed under the GNU Free Documentation License.
Are you an expert in this subject? Join the discussion and share your knowledge at Wikipedia.org.
Columbia River Plateau
From Wikipedia, the free encyclopedia
The Columbia River Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade and Rocky Mountains, cut through by the Columbia River. In common usage, the term 'Columbia Basin' refers to more or less the same area as the Columbia Plateau.[1]
Contents |
During late Miocene and early Pliocene times, one of the largest flood basalts ever to appear on the earth's surface engulfed about 63,000 square miles (160,000 km²) of the Pacific Northwest, forming a large igneous province (the Columbia River Basalt Group).[2] Over a period of perhaps 10 to 15 million years lava flow after lava flow poured out, eventually accumulating to a thickness of more than 6,000 feet (1.8 km).[2] As the molten rock came to the surface, the earth's crust gradually sank into the space left by the rising lava.[2]
The subsidence of the crust produced a large, slightly depressed lava plain now known as the Columbia Basin or Plateau.[2] The ancient Columbia River was forced into its present course by the northwesterly advancing lava. The lava, as it flowed over the area, first filled the stream valleys, forming dams that in turn caused impoundments or lakes.[2] Entities that have been found in these lake beds are fossil leaf impressions, petrified wood, fossil insects, and bones of vertebrate animals.[2]
The Washington cities in the Columbia Plateau include:
Oregon cities in the Columbia Plateau include:
Major tourist attractions include lava flows that were created by the eruptions of the Pliocene and Miocene eras, the Blue Mountains, and the Columbia River.
- USGS Page on Columbia Plateau
- Geology of Lake Roosevelt National Recreation Area (source of much of this page)
- Guide to digital documents and photographs about the Columbia River area.
- Columbia River Basin Ethnic History Archive
|
|
|
|---|---|
| Glacial Lake Missoula · Missoula Floods · Channeled scablands · Grand Coulee · Dry Falls · Drumheller Channels · Columbia River Plateau · Wallula Gap · Touchet Formation · Lake Lewis · Columbia River Gorge · Columbia River Basalt Group · Palouse Falls · Sims Corner Eskers and Kames · Moses Coulee · Withrow Moraine · Crab Creek · Corfu Slide |
 |
