Grand Canyon

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The grand canyon is a steep-sided  carved by the Colorado River in the state of Arizona in the United States. It is contained within and managed by Grand Canyon National Park, the Kaibab National Forest, Grand Canyon-Parashant National Monument, the Hualapai Tribal Nation, the Havasupai people and the Navajo Nation. President Theodore Roosevelt was a major proponent of preservation of the Grand Canyon area, and visited it on numerous occasions to hunt and enjoy the scenery.

The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a mile (6,093 feet or 1,857 meters).[1] Nearly two billion years of Earth's geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted.[2] While the specific geologic processes and timing that formed the Grand Canyon are the subject of debate by geologists,[3] recent evidence suggests that the Colorado River established its course through the canyon at least 17 million years ago.[4][5] Since that time, the Colorado River continued to erode and form the canyon to its present-day configuration.[6]

For thousands of years, the area has been continuously inhabited by Native Americans who built settlements within the canyon and its many caves. The Pueblo people considered the Grand Canyon ("Ongtupqa" in the Hopi language) a holy site, and made pilgrimages to it.[7] The first European known to have viewed the Grand Canyon was García López de Cárdenas from Spain

  1. ^ Kiver, E.P.; Harris, D.V. (1999). Geology of US Parklands. Wiley. p. 902. 
  2. ^ Geologic Formations of the Grand Canyon National Park Service Retrieved 2009-11-17
  3. ^ Ranney, Wayne (2005). Carving Grand Canyon: Evidence, Theories, and Mystery. Grand Canyon Association. ISBN 978-0-938216-82-7. 
  4. ^ "Grand Canyon Still Grand but Older". New York Times. 2008-03-07. 
  5. ^ Polyak, Victor; Hill, Carol; Asmerom, Yemane (2008-03-07). "Age and Evolution of the Grand Canyon Revealed by U-Pb Dating of Water Table-Type Speleothems". Science 319 (5868): 1377–1380. doi:10.1126/science.1151248. PMID 18323451. 
  6. ^ Butler, Bill. "Evolution of the Colorado River and its Tributaries including the Origin and Formation of the Grand Canyon Geologic History of the Grand Canyon". Retrieved 2010-10-22. 
  7. ^ Mitchell, Douglas R.; Lippert, Dorothy; Brunson-Hadley, Judy L. (2004-02-15). Ancient Burial Practices in the American Southwest (reprint, illustrated ed.). Albuquerque, NM: UNM Press. p. 11. ISBN 0-8263-3461-X.