Chinle Formation

There is no designated type locality for this formation. It was named for Chinle Valley in Apache County, Arizona by Herbert E. Gregory in 1917 without officially designating it as the formation's name until two years later and without a specified type locality.[2]

United States Geological Survey economic geologist Raymond C. Robeck in 1956 revised the unnamed members of Gregory by identifying and naming the Temple Mountain member as the basal-most unit in the area of the San Rafael Swell of Utah. In 1957 John H. Stewart revised the Shinarump Conglomerate of G. K. Gilbert, 1875, and Edwin E. Howell, 1875, and Gregory, 1917, and renamed it the Shinarump member of the Chinle formation. An overview of the geology of the area was created by USGS geologist Forrest G. 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.[3]

The Chinle was raised to group status by Lucas in 1993,[4] 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). The Dockum was named in 1890, before the Chinle. Lucas also advocated abandoning the name Dolores Formation as a parochial synonym for the Chinle Group.

Overviews of the Chinle were created by Dubiel and others (1992) and Hintze and Axen (1995).[5]

The formation members and their thicknesses are highly variable across the Chinle. The stratigraphically lowest formation is the Temple Mountain Member. However, in most areas, the basal member is the Shinarump Member.[6] The Shinarump is a braided-river system channel-deposit facies.[3] The Monitor Butte Member overlies the Shinarump in most areas. The Monitor Butte is an overbank (distal floodplain) facies with lacustrine deposits. This is overlain in western areas by the channel-deposit facies Moss Back Member. More commonly, the Monitor Butte grades into the Petrified Forest Member. The Petrified Forest is predominately overbank deposits with thin lenses of channel-deposit facies and lacustrine deposits.

The Petrified Forest Member can be divided into the Lower Petrified Forest Member and Upper Petrified Forest Member in Arizona and New Mexico, separated by the Sonsela Sandstone. The Sonsela Sandstone is a braided-stream channel facies. The Petrified Forest grades into the Owl Rock Member. The Owl Rock is a marginal lacustrine to lacustrine facies possibly representing a large lake system. Finally, either the Rock Point or Church Rock Members overlie the Owl Rock. Some researchers feel the two Members may be synonymous. The two Members are complex heterolithic units, representing variously braided-river facies, lacustrine, and overbank deposits.

The Chinle Formation is aged from early Late Triassic. Age correlation is based on Lucas's Land Vertebrate Faunachrons. The faunachrons are based on first and last appearances of phytosaurs. Simplified stratigraphy based on Litwin.[7]

Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys.

Group rank (alphabetical – rank and formations not recognized by the USGS)[1]

• 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):[1]

• 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)

The Permian through Jurassic stratigraphy of the Colorado Plateau area of southeastern Utah that makes up much of the famous prominent rock formations in protected areas such as Capitol Reef National Park and Canyonlands National Park.
From top to bottom: (youngest to oldest)
5 – Rounded tan domes of the Navajo Sandstone,
4 – layered red Kayenta Formation,
3 – cliff-forming, vertically-jointed, red Wingate Sandstone,
2 – slope-forming, purplish Chinle Formation, layered, lighter-red Moenkopi Formation, and
1 – white, layered Cutler Formation sandstone.
Picture from Glen Canyon National Recreation Area, Utah

Geologic Province:[1]

• Black Mesa Basin*
• Great Basin province*
• Green 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:

• Arches National Park
• Canyonlands National Park – see geology of the Canyonlands area
• Capitol Reef National Park – see geology of the Capitol Reef area
• Colorado National Monument
• Dinosaur National Monument
• Flaming Gorge National Recreation Area
• Glen Canyon National Recreation Area
• Gold Butte National Monument
• Grand Canyon National Park – see geology of the Grand Canyon
• Grand Staircase-Escalante National Monument
• Lake Mead National Recreation Area
• Natural Bridges National Monument
• Petrified Forest National Park
• Red Fleet State Park
• Wupatki National Monument
• Zion National Park – see geology of the Zion and Kolob canyons area
• Red Rock Canyon National Conservation Area

Other:

• Ghost Ranch[8]

Wikimedia Commons has media related to Chinle Formation.

• List of dinosaur-bearing rock formations
• Paleobiota of the Chinle Formation

• Lehman, T.M. (1994). "The saga of the Dockum Group and the case of the Texas/New Mexico boundary fault". New Mexico Bureau of Mines & Mineral Resources Bulletin, v. 150, pp. 37–51.
• Lucas, S.G. (1998). "Global Triassic tetrapod biostratigraphy and biochronology". Palaeogeography, Palaeoclimatology, and Palaeoecology, v. 143, pp. 347–384.

• Spatial distribution of Chinle in Macrostrat
• Chinleana- "Chinle Confusion"