The
Permian Hermit Formation, also known as the Hermit Shale, is a nonresistant unit that is composed of
slope-forming reddish brown
siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...
,
mudstone
Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...
, and very fine-grained
sandstone. Within the
Grand Canyon
The Grand Canyon (, yuf-x-yav, Wi:kaʼi:la, , Southern Paiute language: Paxa’uipi, ) is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is long, up to wide and attains a depth of over a m ...
region, the upper part of the Hermit Formation contains red and white, massive, calcareous sandstone and siltstone beds that exhibit low-angle
cross-bedding. Beds of dark red crumbly siltstone fill shallow
paleochannels that are quite common in this formation. The siltstone beds often contain poorly preserved plant fossils. The Hermit Formation varies in thickness from about in the eastern part of the Grand Canyon region to about in the region of
Toroweap and
Shivwits Plateaus. In the
Sedona, Arizona
Sedona is a city that straddles the county line between Coconino and Yavapai counties in the northern Verde Valley region of the U.S. state of Arizona. As of the 2010 census, its population was 10,031. It is within the Coconino National Fo ...
area, it averages in thickness. The upper contact of the Hermit Formation is typically sharp and lacks
gradation of any kind. The lower contact is a
disconformity characterized by a significant amount of
erosional
relief, including paleovalleys as much as deep.
See also
*
Geology of the Grand Canyon area
References
Popular Publications
* Blakey, Ron and Wayne Ranney, ''Ancient Landscapes of the Colorado Plateau,'' Grand Canyon Association (publisher), 2008, 176 pages,
* Chronic, Halka. ''Roadside Geology of Arizona,'' Mountain Press Publishing Co., 1983, 23rd printing, pp. 229–232,
* Lucchitta, Ivo, ''Hiking Arizona's Geology,'' 2001, Mountaineers's Books,
External links
* 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.
* Shur, C., and D. Shur (2008
{{Chronostratigraphy of Nevada
Sandstone formations of the United States
Natural history of the Grand Canyon
Geologic formations of Arizona
Geologic formations of Nevada
Geologic formations of Utah
Permian Arizona
Permian geology of Nevada
Permian geology of Utah
Cisuralian Series of North America