Chinle Formation
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The Chinle is a geologic formation that is spread across the U.S. states of Texas, New Mexico, northern Arizona, Nevada, Utah, and western Colorado. This geologic unit is part of the Dockum Group in Colorado, New Mexico and Texas and is sometimes locally considered to be a geologic group in New Mexico and Texas. Part of the Colorado Plateau, the Basin and Range, and the southern section of the Interior Plains, this formation was laid down in the Late Triassic.[1]
Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys.
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[edit] History of investigation
There is no designated type locality for this formation. It was named for Chinle Valley in Apache County, Arizona by Gregory in 1917 (he first used the name two years before but did not indicate a wish to officially name it). Members were first assigned by Robeck in 1956 and Stewart in 1957. An overview was created by Poole and Stewart in 1964. Sikich revised the unit and assigned more members assigned in 1965. The areal extent of the unit was mapped by Wilson and Stewart in 1967. In 1972 the areal limits were modified and an overview created by Stewart and others (they published a revision the same year). Kelley assigned more members and revised the unit in 1972. Lucas and Hayden did the same thing in 1989. The Rock Point Member was assigned by Dubiel in 1989. The Chinle was raised to group status by Lucas in 1993, thus also raising many of the members to formation status. He also included the formations of the Dockum Group of eastern New Mexico and west Texas within the Chinle Group. This modified nomenclature is controversial; many still retain the Chinle as a formation and separate out the Dockum Group (e.g., USGS). Overviews were created by Dubiel and others (1992) and Hintze and Axen (1995).[2]
[edit] Subunits
Group rank (alphabetical - rank and formations not recognized by the USGS):[3]
- San Pedro Arroyo Formation (NM),
- Santa Rosa Formation (NM),
- Shinarump Formation (NM).
- Petrified Forest Formation (AZ, UT, NM)
- Many others - see members below
Formation rank (alphabetical - several members not recognized by the USGS):[4]
- Agua Zarca Sandstone Member (NM),
- Bluewater Creek Member (AZ,CO,NM),
- Church Rock Member (AZ*,CO*,UT*),
- Correo Sandstone Member (NM),
- Cuervo Sandstone Member (NM),
- Duffin Sandstone Member (UT),
- Gartra Member (CO*,UT*),
- Mesa Redondo Member (AZ*,NM*),
- Monitor Butte Member (AZ*,CO*,UT*),
- Moss Back Member (AZ*,CO*,UT*),
- Newspaper Rock Sandstone Bed (AZ),
- Owl Rock Member (AZ*,NM*,UT*),
- Petrified Forest Member (AZ*,CO*,NV*,NM*,UT*),
- Poleo Sandstone Lentil (NM),
- Redonda Member (NM),
- Rock Point Member (AZ*,NM*),
- Salitral Shale Tongue (NM*),
- Shinarump Member (AZ*,NV*,NM*,UT*),
- Silver Reef Sandstone Member (UT),
- Stanaker Member (UT),
- Temple Mountain Member (UT*),
- Trail Hill Sandstone [Member] (UT).
[edit] Places found
Geologic Province:[5]
- Black Mesa Basin*
- Great Basin province*
- Geen River Basin*
- Las Vegas-Raton Basin*
- Orogrande Basin
- Palo Duro Basin*
- Paradox Basin*
- Permian Basin
- Piceance Basin*
- Plateau sedimentary province*
- San Juan Basin*
- Sierra Grande Uplift*
- Uinta Basin*
- Uinta Uplift*
- Wasatch Uplift*
Parklands (incomplete list):
- Canyonlands National Park - see geology of the Canyonlands area
- Capitol Reef National Park - see geology of the Capitol Reef area
- Glen Canyon National Recreation Area - see geology of the Glen Canyon area
- Petrified Forest National Park - see geology of the Petrified Forest area
- Zion National Park - see geology of the Zion and Kolob canyons area
[edit] References
[edit] Works cited
- GEOLEX database entry for Chinle, USGS (viewed 19 March 2006)
- GEOLEX database bibliographic references for Chinle (viewed 19 March 2006)
