Grand Canyon (redirected from Grand canynon)

Grand Canyon, great gorge of the Colorado River, one of the natural wonders of the world; c.1 mi (1.6 km) deep, from 4 to 18 mi (6.4–29 km) wide, and 217 mi (349 km) long, NW Ariz. The canyon shows in its rocks the repeated geological sequence of uplift, erosion (due to the river's constant wearing force), submergence, and deposition of materials. The multicolored rocks, the steep and embayed rims, and the isolated towers, mesas, "temples," and other eroded rock forms catch the contrast of sun and shadow and glow with changing hues of great beauty. Plant life on the canyon walls varies from subtropical at the base to subarctic near the rims. Hundreds of ancient pueblos dot the lower canyon walls and the rim. The Havasupai people still occupy a part of the canyon, and the Hualapai reservation encompasses much of the south rim. (The Hualapai now operate a visitors center, including a skywalk projecting over the canyon rim.) The first European to see the canyon was the Spanish explorer García López de Cárdenas in 1540. In 1869 the U.S. explorer John Wesley Powell became the first person to lead a party through the canyon bottom in a boat.

The Grand Canyon was set aside by the U.S. government in 1908 as a national monument. In 1919 an expanded area was designated

Grand Canyon National Park (1,217,403 acres/492,876 hectares). The park was enlarged in 1975 to include other areas, such as Marble Canyon and parts of Glen Canyon and Lake Mead. Along the forested northern rim and the more accessible southern rim are numerous lookouts, and trails wind to the canyon floor. Raft and boat excursions along the canyon's river bottom are popular. In 2000 the lands north of the western portion of the canyon, an area almost the size of the park, were designated

Grand Canyon–Parashant National Monument (1,014,000 acres/410,670 hectares). See National Parks and Monuments (table).

Bibliography

See S. Whitney, A Field Guide to the Grand Canyon (1987); J. W. Krutch, Grand Canyon (1989); S. J. Pyne, How the Canyon Became Grand (1998).

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Grand Canyon

Extensive canyon system cut by the Colorado River, northwestern Arizona, U.S. Noted for its rock formations and coloration, it is about 0.1–18 mi (0.2–29 km) wide and extends from northern Arizona to Grand Wash Cliffs, near the Nevada border, a distance of about 277 mi (446 km). The deepest section, 56 mi (90 km) long, is within Grand Canyon National Park, which covers the river's length from Lake Powell to Lake Mead. The surrounding plateau is 6,000–9,000 ft (1,800–2,750 m) above sea level, and the canyon is in places more than 1 mi (1.6 km) deep. The national park, now containing 1,904 sq mi (4,931 sq km), was created in 1919. The former Grand Canyon National Monument, established in 1932, was added, with other lands, in 1975. In 1979 the Grand Canyon was designated a UNESCO World Heritage site.

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Grand Canyon

a gorge of the Colorado River in N Arizona, extending from its junction with the Little Colorado River to Lake Mead; cut by vertical river erosion through the multicoloured strata of a high plateau; partly contained in the Grand Canyon National Park, covering 2610 sq. km (1008 sq. miles). Length: 451 km (280 miles). Width: 6 km (4 miles) to 29 km (18 miles). Greatest depth: over 1.5 km (1 mile)

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Grand Canyon 

Grand Canyon of the Colorado River, a canyon in the state of Arizona (USA), in the middle course of the Colorado River, on the Colorado Plateau. It is one of the deepest canyons in the world. It extends 320 km downstream from the basin of the Little Colorado. The canyon is up to 1,800 m deep; its width at the level of the plateau surface (elevation 2,100–2,400 m) is 8–25 km, but less than 1km where the river waters cut through (at individual spots it is up to 120 m). The steep and often strongly dissected slopes abound with shoulders in the shape of bastions, columns, and pyramids. The Colorado River cuts through horizontal layers of rock from Archean crystalline to upper Paleozoic sedimentary rocks—limestone, sandstone, and shale, and others—with variegated coloring. The canyon was formed in the Cenozoic period as a result of erosion by the Colorado River, strengthened by the gradual rising of the plateau. The Colorado River falls an average of 1.5 m per km in the Grand Canyon and flows with a velocity of up to 25 km per hr. The Grand Canyon is picturesque and attracts a large number of tourists; it is a national park.