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an immense gorge cut by the Colorado River into the high plateau in the northwestern corner of Arizona that ranges in width from 4 to 18 miles and is about 280 miles long
The Canyon was formed by the ceaseless cutting of the silt-laden Colorado River, accelerated by storm waters that occasionally fall into the Canyon, and by weathering processes. While the river has been cutting its way downward, the land in the plateau region that surrounds it has been gradually rising. Most geologists agree that the canyon is "only" about six to eight million years old, making it one of the newest geologic features on Earth.
Although the canyon is "new" the beds of rock exposed in it are old, and they tell a story that began hundreds of millions of years ago. Most of the layers of rock in the walls of the canyon are sandstone, limestone, and shale. These rocks are water-made, meaning that for millions of years this region was actually under the sea. At the very bottom of the canyon the rock is granite, which was formed from hot liquid rock like the lava that pours out of volcanoes. This layer was formed long before the days of the dinosaurs, even before the time when trilobites were the earth's leading animals.
The first white man to see the Grand Canyon was Garcia López de Cárdenas, who about 1540 was sent from Zuñi, New Mexico, to find a river far to the west, the existence of which had been learned from the natives. In 1854 Lieutenant A.W. Whipple followed the lower course of the Colorado River as far up as the mouth of Diamond creek. In 1857 Lieutenant J.C. Ives travelled through the gorge of Diamond Creek and eastward to Havasu Canyon, the San Francisco Mountains, the Little Colorado and the country of the Hopi Indians.
Grand Canyon National Park, which includes 250 miles of the most magnificent and deepest part of the Grand Canyon of the Colorado, was created by the United States Congress in 1919. Numerous observation platforms provide wonderful panoramic views of the canyon, and there are dozens of trails that take visitors from the rim to the river.
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This page was last updated on October 13, 2017.