Snake River Plain
43°00′N 113°30′W / 43.000°N 113.500°W
The Snake River Plain is a geologic feature located primarily within the U.S. state of Idaho. It stretches about 400 miles (640 km) westward from northwest of the state of Wyoming to the Idaho-Oregon border. The plain is a wide, flat bow-shaped depression and covers about a quarter of Idaho. Three major volcanic buttes dot the plain east of Arco, the largest being Big Southern Butte.
Most of Idaho's major cities are in the Snake River Plain, as is much of its agricultural land.
Geology
The
The eastern Snake River Plain traces the path of the North American Plate over the Yellowstone hotspot, now centered in Yellowstone National Park. The eastern plain is a topographic depression that cuts across Basin and Range mountain structures, more or less parallel to North American Plate motion. It is underlain almost entirely by basalt erupted from large shield volcanoes. Beneath the basalts are rhyolite lavas and ignimbrites that erupted as the lithosphere passed over the hotspot.
The central Snake River plain is similar to the eastern plain but differs by having thick sections of interbedded lacustrine (lake) and fluvial (stream) sediments, including the Hagerman fossil beds.
Effects on climate
The Snake River Plain has a significant effect on the climate of
Although the topography of the Plain has largely gone unchanged for several million years, this region's climate has not been so constant. Current climatic conditions began to characterize the region in the early Pleistocene (approximately 2.5 million years ago). However, the arid climate of today was born from the gradual dissipation of a climate defined by greater moisture and narrower ranges of annual temperatures.[3][4]
See also
References
- ^ Bryson, R. A. and Hare, F.K. 1974 Climates of North America, Survey of Climatology, Vol. 11 Elsevier, New York p 422
- ^ Mock, C. J., 1996 Climatic controls and spatial variations of precipitation in the western United States, Journal of Climate, 9:1111-1125
- hdl:2027.42/31761.
- .
External links
- The Snake River Plain Archived 2012-07-17 at the Wayback Machine
- Snake River Plain at Digital Atlas of Idaho