Search results
Results from the WOW.Com Content Network
Grand Canyon, Arizona, at the confluence of the Colorado River and Little Colorado River.. A canyon (from Spanish: cañón; archaic British English spelling: cañon), [1] gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. [2]
The oldest beds of this formation belong to the Dinosaur Canyon Member, a reddish, slope-forming rock layer with thin beds of siltstone that are interbedded with mudstone and fine sandstone. [11] The Dinosaur Canyon, with a local thickness of 140 to 375 feet (43 to 114 m), was probably laid down in slow-moving streams, ponds and large lakes. [7]
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]
Grand Canyon [a] is a steep-sided canyon carved by the Colorado River in Arizona, United States. 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 ...
The hills have long since eroded away over time, while the stronger basalt rocks remained, which eventually cracked and formed canyons and escarpments. As time progressed, more eruptions occurred and thicker lava cooled to form the now-extinct volcanic cones to the west of the monument; these cones can be seen from the top of the mesa.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Except where underlain by the Sixtymile Formation, the Tapeats Sandstone is the Cambrian geologic formation that is the basal geologic unit of the Tonto Group.Typically, it is also the basal geologic formation of the Phanerozoic strata exposed in the Grand Canyon, Arizona, and parts of northern Arizona, central Arizona, southeast California, southern Nevada, and southeast Utah.