Uinkaret volcanic field
|Uinkaret volcanic field|
|Elevation||1,555 m (5,102 ft) |
|Location||Mohave County, Arizona, US|
|Topo map||USGS Mount Logan|
|Age of rock||1.2 million years |
|Mountain type||volcanic field|
|Last eruption||1100 ± 75 years|
Lava flows from the Uinkaret volcanic field that have cascaded down into the Grand Canyon, damming the Colorado River, have been used to date the canyon's carving.  One of these cascades is today's Lava Falls. Lava Falls Rapid, below Lava Falls on the Colorado River, is "at all water levels, the most severe rapid in Grand Canyon." 
The Colorado River was dammed by lava flows multiple times from 725,000 to 100,000 years ago.  While some believe that these lava dams were stable, lasting up to 20,000 years and forming large reservoirs,  others think they failed quickly and catastrophically as massive floods.  Lava flows traveled downriver 76 miles (121 km) from river mile 178 to 254.[ citation needed]
One lava flow, from Little Springs, south of Pliocene Mount Trumbull, has a cosmogenic helium age of 1300 +/- 500 years BP. Pottery shards dated to between A.D. 1050 and 1200 were found within the lava flow, produced around the same time as the Sunset Crater eruption in the San Francisco volcanic field on the South Rim. 
|Mount Emma ||-||-||-||-|
|Little Springs ||-||-||-||1050-1200 AD|
|Prospect Cone ||-||-||-||-|
|Mount Trumbull ||-||-||-||-|
|Vulcan's Forge ||-||-||-||-|
|Vulcan's Throne  ||-||-||-||73,000 years ago|
- "Uinkaret Field". Global Volcanism Program. Smithsonian Institution.
- Wood, Charles A.; Jűrgen Kienle (1993). Volcanoes of North America. Cambridge University Press. pp. 277–278. ISBN 0-521-43811-X.
- "Grand Canyon National Park - Geologic Formations (U.S. National Park Service)". U.S. National Park Service. 2007-03-29. Retrieved 2007-05-24.
- New Debris Flow at Lava Falls, at Grand Canyon River Guides. Accessed 5/26/09.
- Karlstrom, K., Crow, R., Peters, L., McIntosh, W., Raucci, J., Crossey, L., and Umhoefer, P., 2007, 40Ar/39Ar and field studies of Quaternary basalts in Grand Canyon and model for carving Grand Canyon: Quantifying the interaction of river incision and normal faulting across the western edge of the Colorado Plateau: GSA Bulletin, v. 119, no. 11/12, p. 1283-1312.
- Hamblin, W.K., 1994, Late Cenozoic lava dams in the western Grand Canyon: Geological Society of America Memoir 183, 139 p.
- Fenton, C.R., Poreda, R.J., Nash, B.P., Webb, R.H., and Cerling, T.E., 2004, Geochemical discrimination of five Pleistocene lava-dam outburst-flood deposits, western Grand Canyon, Arizona: The Journal of Geology, v. 112, p. 91–110, doi: 10.1086/379694.
- "Uinkaret Field: Synonyms and Subfeatures". Global Volcanism Program. Smithsonian Institution. Retrieved 2007-05-23.
- Uinkaret Volcanic Field, Western Grand Canyon, Arizona at Volcano World
- Full-size version of image in infobox, NASA ASTER satellite image.
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