Chinle Formation
Encyclopedia
The Chinle is a geologic formation
that is spread across the U.S. state
s of northern Arizona
, Nevada
, Utah
, western New Mexico
, and western Colorado
. The Chinle is controversially considered to be synonymous to the Dockum Group
in eastern Colorado, eastern New Mexico, southwestern Kansas
, the Oklahoma
panhandle, and western Texas
. The Chinle is sometimes colloquially used as a geologic formation
within the Dockum in New Mexico and occasionally in 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
.
A probable separate depositional basin within the Chinle is found in northwestern Colorado and northeastern Utah. In the southern portion of the Chinle, it reaches a maximum thickness of a little over 520 m. Typically, the Chinle rests unconformably
on the Moenkopi Formation
.
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). It should be pointed out that the Dockum was named in 1890, before the Chinle. If Lucus is correct, his "Chinle Group" should be named the Dockum Group due to stratigraphic nomenclature rules. Overviews of the Chinle were created by Dubiel and others (1992) and Hintze and Axen (1995).
. 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.
s. Simplified stratigraphy
based on Litwin.
Group rank (alphabetical - rank and formations not recognized by the USGS)
Formation rank (alphabetical - several members not recognized by the USGS):
Parklands (incomplete list):
Geologic formation
A formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...
that is spread across the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
s of northern Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
, Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
, western New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, and western Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
. The Chinle is controversially considered to be synonymous to the Dockum Group
Dockum Group
The Dockum is a Late Triassic geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Colorado, and Oklahoma panhandle. The Dockum reaches a maximum thickness of slightly over 650 m but is usually much...
in eastern Colorado, eastern New Mexico, southwestern Kansas
Kansas
Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...
, the Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
panhandle, and western Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
. The Chinle is sometimes colloquially used as a geologic formation
Geologic formation
A formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...
within the Dockum in New Mexico and occasionally in Texas. Part of the Colorado Plateau
Colorado Plateau
The Colorado Plateau, also called the Colorado Plateau Province, is a physiographic region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. The province covers an area of 337,000 km2 within western Colorado, northwestern New Mexico,...
, the Basin and Range
Basin and Range
The Basin and Range Province is a vast physiographic region defined by a unique topographic expression. Basin and Range topography is characterized by abrupt changes in elevation, alternating between narrow faulted mountain chains and flat arid valleys or basins...
, and the southern section of the Interior Plains
Interior Plains
The Interior Plains is a vast physiographic region that spreads across the Laurentian craton of central North America.-Geography:The Interior Plains are an extensive physiographic division encompassing 8 distinct physiographic provinces, the Interior Low Plateaus, Great Plains, Central Lowland,...
, this formation was laid down in the Late Triassic
Late Triassic
The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...
.
A probable separate depositional basin within the Chinle is found in northwestern Colorado and northeastern Utah. In the southern portion of the Chinle, it reaches a maximum thickness of a little over 520 m. Typically, the Chinle rests unconformably
Unconformity
An unconformity is a buried erosion surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger, but the term is used to describe...
on the Moenkopi Formation
Moenkopi Formation
The Moenkopi is a geological formation that is spread across the U.S. states of New Mexico, northern Arizona, Nevada, southeastern California, eastern Utah and western Colorado. This unit is considered to be a group in Arizona. Part of the Colorado Plateau and Basin and Range, this formation was...
.
History of investigation
There is no designated type localityType locality (geology)
Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....
for this formation. It was named for Chinle
Chinle, Arizona
Chinle is a census-designated place in Apache County, Arizona, United States. The population was 5,366 at the 2000 census.-Geography:Chinle is located at ....
Valley in Apache County, Arizona
Apache County, Arizona
-2010:Whereas according to the 2010 U.S. Census Bureau:*23.3% White*0.2% Black*72.9% Native American*0.3% Asian*0.0% Native Hawaiian or Pacific Islander*2.0% Two or more races*1.3% Other races*5.8% Hispanic or Latino -2000:...
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
Dockum Group
The Dockum is a Late Triassic geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Colorado, and Oklahoma panhandle. The Dockum reaches a maximum thickness of slightly over 650 m but is usually much...
of eastern New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
and west Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
within the "Chinle Group" . This modified nomenclature is controversial; many still retain the Chinle as a formation and separate out the Dockum Group
Dockum Group
The Dockum is a Late Triassic geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Colorado, and Oklahoma panhandle. The Dockum reaches a maximum thickness of slightly over 650 m but is usually much...
(e.g., USGS). It should be pointed out that the Dockum was named in 1890, before the Chinle. If Lucus is correct, his "Chinle Group" should be named the Dockum Group due to stratigraphic nomenclature rules. Overviews of the Chinle were created by Dubiel and others (1992) and Hintze and Axen (1995).
Stratigraphy
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. The Shinarump is a braided-river system channel-deposit faciesFacies
In geology, facies are a body of rock with specified characteristics. Ideally, a facies is a distinctive rock unit that forms under certain conditions of sedimentation, reflecting a particular process or environment....
. The Monitor Butte Member overlies the Shinarump in most areas. The Monitor Butte is an overbank (distal floodplain
Floodplain
A floodplain, or flood plain, is a flat or nearly flat land adjacent a stream or river that stretches from the banks of its channel to the base of the enclosing valley walls and experiences flooding during periods of high discharge...
) facies with lacustrine
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
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.
Ages of Chinle Members
Age correlation based on Lucas' Land Vertebrate Faunachrons. The faunachrons are based on first and last appearances of phytosaurPhytosaur
Phytosaurs are an extinct group of large semi-aquatic Late Triassic archosaurs. Phytosaurs belong to the family Phytosauridae and the order Phytosauria. They were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodiles in size, appearance, and lifestyle, an example...
s. Simplified stratigraphy
Stratigraphy
Stratigraphy, a branch of geology, studies rock layers and layering . It is primarily used in the study of sedimentary and layered volcanic rocks....
based on Litwin.
| Sub-stage | Faunachron | Chinle Member(s) |
|---|---|---|
| Late Norian Norian The Norian is a division of the Triassic geological period. It has the rank of an age or stage . The Norian lasted from 216.5 ± 2.0 to 203.6 ± 1.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.-Stratigraphic definitions:The Norian was named after the Noric Alps in... -Rhaetian Rhaetian The Rhaetian is in geochronology the latest age of the Triassic period or in chronostratigraphy the uppermost stage of the Triassic system. It lasted from 203.6 ± 1.5 to 199.6 ± 0.6 million years ago... |
Apachean | Rock Point/Church Rock |
| Early to Middle Norian | Revueltian | Owl Rock Upper Petrified Forest |
| upper Late Carnian Carnian The Carnian is the lowermost stage of the Upper Triassic series . It lasted from about 228.7 till 216.5 million years ago . The Carnian is preceded by the Ladinian and is followed by the Norian... |
Adamanian | Sonsela Sandstone Lower Petrified Forest Moss Back Monitor Butte |
| lower Late Carnian | Otischalkian | Shinarump Temple Mountain |
Subunits
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)
- 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):
- 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).
Places found
Geologic Province:- Black Mesa Basin*
- Great BasinGreat BasinThe Great Basin is the largest area of contiguous endorheic watersheds in North America and is noted for its arid conditions and Basin and Range topography that varies from the North American low point at Badwater Basin to the highest point of the contiguous United States, less than away at the...
province* - Geen River Basin*
- Ghost RanchGhost RanchGhost Ranch is a retreat and education center located close to the village of Abiquiu in Rio Arriba County in north central New Mexico. The conference center and lodgings at Ghost Ranch are run by the Presbyterian Church but open to the general public.-History:Ghost Ranch is part of Piedra...
* - Las Vegas-Raton Basin*
- Orogrande Basin
- Palo Duro Basin*
- Paradox BasinParadox BasinThe Paradox Basin is an asymmetric foreland basin located mostly in southeast Utah and southwest Colorado, but extending into northeast Arizona and northwest New Mexico. The basin is a large elongate northwest to southeast oriented depression formed during the late Paleozoic Era...
* - Permian Basin
- Piceance BasinPiceance BasinThe Piceance Basin is a geologic structural basin in northwestern Colorado, in the United States. It includes geologic formations from Cambrian to Holocene in age, but the thickest section is made up of rocks from the Cretaceous Period...
* - Plateau sedimentary province*
- San Juan BasinSan Juan BasinThe San Juan Basin is a geologic structural basin in the Four Corners region of the Southwestern United States; its main portion covers around , encompassing much of northwestern New Mexico, southwest Colorado, and parts of Arizona and Utah....
* - Sierra Grande Uplift*
- Uinta Basin*
- Uinta Uplift*
- Wasatch Uplift*
Parklands (incomplete list):
- Canyonlands National ParkCanyonlands National ParkCanyonlands National Park is a U.S. National Park located in southeastern Utah near the town of Moab and preserves a colorful landscape eroded into countless canyons, mesas and buttes by the Colorado River, the Green River, and their respective tributaries. The park is divided into four districts:...
- see geology of the Canyonlands areaGeology of the Canyonlands areaThe exposed geology of the Canyonlands area is complex and diverse; 12 formations are exposed in Canyonlands National Park that range in age from Pennsylvanian to Cretaceous. The oldest and perhaps most interesting was created from evaporites deposited from evaporating seawater... - Capitol Reef National ParkCapitol Reef National ParkCapitol Reef National Park is a United States National Park, in south-central Utah. It is 100 miles long but fairly narrow. The park, established in 1971, preserves 378 mi² and is open all year, although May through September are the most popular months.Called "Wayne Wonderland" in the 1920s...
- see geology of the Capitol Reef areaGeology of the Capitol Reef areaThe exposed geology of the Capitol Reef area presents a record of mostly Mesozoic-aged sedimentation in an area of North America in and around Capitol Reef National Park. Nearly 10,000 feet of sedimentary strata are found in the Capitol Reef area, representing nearly 200 million years of... - Glen Canyon National Recreation AreaGlen Canyon National Recreation AreaGlen Canyon National Recreation Area is a recreation and conservation unit of the National Park Service that encompasses the area around Lake Powell and lower Cataract Canyon in Utah and Arizona, covering 1,254,429 acres of mostly desert...
- see geology of the Glen Canyon area - Petrified Forest National ParkPetrified Forest National ParkPetrified Forest National Park is a United States national park in Navajo and Apache counties in northeastern Arizona. The park's headquarters are about east of Holbrook along Interstate 40 , which parallels a railroad line, the Puerco River, and historic U.S. Route 66, all crossing the park...
- see geology of the Petrified Forest area - Zion National ParkZion National ParkZion National Park is located in the Southwestern United States, near Springdale, Utah. A prominent feature of the park is Zion Canyon, which is 15 miles long and up to half a mile deep, cut through the reddish and tan-colored Navajo Sandstone by the North Fork of the Virgin River...
- see geology of the Zion and Kolob canyons areaGeology of the Zion and Kolob canyons areaThe geology of the Zion and Kolob canyons area includes nine known exposed formations, all visible in Zion National Park in the U.S. state of Utah. Together, these formations represent about 150 million years of mostly Mesozoic-aged sedimentation in that part of North America...