Search results
Results from the WOW.Com Content Network
The resulting Grand Canyon Supergroup of sedimentary units is composed of nine varied geologic formations that were laid down from 1.2 billion and 740 million years ago in this sea. [11] Good exposures of the supergroup can be seen in eastern Grand Canyon in the Inner Gorge and from Desert View, Lipan Point and Moran point. [12] [note 1]
The Grand Canyon [a] is a steep-sided canyon carved by the Colorado River in Arizona, United States.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).
The Mesoproterozoic formations in the Grand Canyon are overlain by the 850 million year old, Neoproterozoic Chuar Group and Sixtymile Formation sedimentary rocks. The Great Unconformity is a famous gap in the stratigraphic record of the Grand Canyon of 900 million years between Proterozoic granitic rocks and Cambrian marine sediments. For the ...
Current archaeological evidence suggests that humans inhabited the Grand Canyon area as far back as 4,000 years ago [1] and at least were passers-through for 6,500 years before that. [2] Radiocarbon dating of artifacts found in limestone caves in the inner canyon indicate ages of 3,000 to 4,000 years. [ 1 ]
Theodore Roosevelt created the Grand Canyon Game Preserve by proclamation on November 28, 1906, [9] and the Grand Canyon National Monument on January 11, 1908. [10] Further Senate bills to establish the site as a national park were introduced and defeated in 1910 and 1911, before the Grand Canyon National Park Act ( Pub. L. 65–277 ) was ...
Geologic stratigraphic column of strata exposed in and near the Grand Canyon. The term Great Unconformity is frequently applied to the unconformity observed by John Wesley Powell in the Grand Canyon in 1869. [1] It is an exceptional example of relatively young sedimentary rock strata overlying much older sedimentary or crystalline strata.
The Colorado Plateau which includes the Grand Canyon is the result of broad tectonic uplift followed by river erosion. [ 4 ] When mountains rise slowly, either due to orogenic uplift or other processes (e.g., rebound after glaciation ), an unusual feature known as a water gap may occur.
Mathis, A, and C Bowman (2007) The Grand Age of Rocks: The Numeric Ages for Rocks Exposed within Grand Canyon, Grand Canyon National Park, Arizona, National Park Service, Grand Canyon National Park, Arizona. Noble, FL (1914) Geologic Map and Section of the Shinumo Quadrangle, Arizona.