Redwall Limestone
Stratigraphic range: Early and early Late Mississippian[1][2]
Redwall Limestone cliff, and upper platform of cliff extension (resting on very short Muav Limestone cliff), from Tower of Set, central Grand Canyon, adjacent Granite Gorge.
The bottom of Redwall cliffs typically rest on sections of Temple Butte Formation-(locally), or attached sections of Muav Limestone cliffs (regionally exposed in Grand Canyon, elsewhere in Arizona, not always with surface exposure).
TypeGeological formation
UnderliesSurprise Canyon Formation (Surprise Canyon Formation locally fills paleovalleys, caves, and collapse structures cut into the underlying Redwall Limestone.)
OverliesMuav Limestone and Temple Butte Formation
Thickness800 feet (240 m), at maximum
Lithology
Primaryfossiliferous limestone
Otherdolomite and chert
Location
RegionNorthern Arizona, southeast California, New Mexico, and southern Utah, Nevada
CountryUnited States of America
Type section
Named forthe red appearance of its escarpment on either side of the Grand Canyon[3]
Named byGilbert (1875)[3]

The Redwall Limestone is a resistant cliff-forming unit of Mississippian age that forms prominent, red-stained cliffs in the Grand Canyon, ranging in height from 500 feet (150 m) to 800 feet (240 m).

Lithology

Redwall Limestone consists predominantly of light-olive-gray to light-gray, fine- to coarse-grained, thin- to thick-bedded, often cherty, limestone. Its lower part consists of brownish-gray, interbedded finely crystalline dolomite and fine- to coarse-grained limestone with layers of white chert lenses and yellowish-gray and brownish-gray, cliff-forming, thick-bedded, fine-grained dolomite. It is divided into Horseshoe Mesa Member, Mooney Falls Member, Thunder Springs Member, and Whitmore Wash Member.[1][4] Its origins date to the Mississippian age.

Contacts

The upper and lower contacts of the Redwall Limestone are both unconformities. Locally, the Redwall Limestone directly overlies the unconformity that forms its lower contact consisting of a basal conglomerate. This basal conglomerate is typically composed of gravel that is locally derived from either the underlying Temple Butte Formation or Muav Limestone. The Temple Butte Formation consists of a thin layer of Devonian strata that fills paleovalleys cut into the underlying Cambrian Muav Limestone. Outside of the paleovalleys, the Redwall Limestone overlies the Muav Limestone.[1]

The upper contact of the Redwall Limestone consists of a deeply eroded disconformity characterized by deeply incised paleovalleys and deep paleokarst depressions that are often filled by sediments of the Surprise Canyon Formation.[1][5]

See also

References

  1. 1 2 3 4 Beus, SS (2003) "Redwall Limestone and Surprise Canyon Formation." in: Beus, S.S., Morales, M., eds., pp. 115–134, Grand Canyon Geology, 2nd. Oxford University Press, New York.
  2. ↑ Anonymous (2006) Stratigraphy of the Parks of the Colorado Plateau. U.S. Geological Survey, Reston, Virginia.
  3. 1 2 Gilbert, GK (1875) Chapter 6 Report upon the geology of portions of Nevada, Utah, California, and Arizona. in GM Wheeler, ed., pp. 17–187, Report on the geographical and geological explorations and surveys west of the One hundredth meridian. Publication of the Wheeler Survey, U.S. Geological and Geographical Survey, Washington, DC.
  4. ↑ Chronic, H (1983) Roadside Geology of Arizona. The Mountaineers Books, Seattle, Washington. (softcover, ISBN 978-0-87842-147-3)
  5. ↑ Kenny, R (2010) Continental paleoclimate estimates from the late Mississippian Redwall karst event: northern and north-central Arizona (USA). Carbonates Evaporites. 25(4):297–302

Further reading

  • Blakey, Ron and Wayne Ranney, Ancient Landscapes of the Colorado Plateau, Grand Canyon Association (publisher), 2008, 176 pages, ISBN 978-1934656037
  • Chronic, Halka. Roadside Geology of Arizona, Mountain Press Publishing Co., 1983, 23rd printing, pp. 229–232, ISBN 978-0-87842-147-3
  • Lucchitta, Ivo, Hiking Arizona's Geology, 2001, Mountaineers's Books, ISBN 0-89886-730-4
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