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The Columbia River Basalt Group (including the Steen and Picture Gorge basalts) extends over portions of four states. The Columbia River Basalt Group (CRBG) is the youngest, smallest and one of the best-preserved continental flood basalt provinces on Earth, covering over 210,000 km 2 (81,000 sq mi) mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada. [1]
A flood basalt (or plateau basalt [1]) is the result of a giant volcanic eruption or series of eruptions that covers large stretches of land or the ocean floor with basalt lava. Many flood basalts have been attributed to the onset of a hotspot reaching the surface of the Earth via a mantle plume . [ 2 ]
The resource was first mined in 1898, 11 years after the State Geologist, John Branner, identified it in a sample from Pulaski County, Arkansas. In addition to the deposit in Pulaski County, south and east of Little Rock, there is a second deposit in Saline County, Arkansas close to Benton.
This article is a list of rivers in the U.S. state of Arkansas. ... two Saline Rivers in Arkansas. Flow of rivers differs substantially between years and seasons ...
Basalt is distinguished from andesite by SiO 2 < 52%. Basalt is field B in the TAS classification. Vesicular basalt at Sunset Crater, Arizona. US quarter (24mm) for scale. Columnar basalt flows in Yellowstone National Park, US. Basalt is composed mostly of oxides of silicon, iron, magnesium, potassium, aluminum, titanium, and calcium.
Location of Arkansas in the United States. Arkansas is located in the southeastern United States, in the West South Central Census Bureau division. Arkansas covers an area of 53,179 square miles (137,733 km²) and ranks as the 29th largest state by size. [7]
Columbia River Basalt Group [g] Chilcotin Plateau Basalts [e] Increased Antarctic deep waters Yellowstone hotspot Nördlinger Ries (14.5-14.3) Burdigalian: 20.44 Aquitanian: 23.03 * Shield volcanoes of Ethiopia [h] Antarctic ice sheet complete Paleogene: Oligocene: Chattian: 28.1 Ethiopian and Yemen traps (31–30) [h] Fish Canyon Tuff (27.51 ...
Level III subdivides the continent into 182 ecoregions; of these, seven lay partly within Arkansas's borders. Level IV is a further subdivision of Level III ecoregions. There are 32 Level IV ecoregions in Arkansas, [2] many of which continue into adjacent areas in the neighboring states of Oklahoma, Mississippi, Missouri, Louisiana, Tennessee ...