Glen Canyon Group
Encyclopedia
The Glen Canyon Group is a geologic group of formations that is spread across the U.S. state
s of Nevada
, Utah
, northern Arizona
, north west New Mexico
and western Colorado
. It is sometimes called the Glen Canyon Sandstone in Colorado and Utah. There are four formations within the group. From oldest to youngest, these are the Wingate Sandstone
, Moenave Formation
, Kayenta Formation
, and Navajo Sandstone
. Part of the Colorado Plateau
and the Basin and Range
, this group of formations was laid down during the Late Triassic
and Early Jurassic
, with the Triassic-Jurassic boundary within the Wingate Sandstone. The top of the Glen Canyon Group is thought to date to the Toarcian
stage of the Early Jurassic.
Asterisks (*) below indicate usage by the U.S. Geological Survey.
for this group. It was named by Gregory and Moore in 1931 for exposures in walls that form the Glen Canyon
of the Colorado River in Coconino County, Arizona
and San Juan County, Utah
. An overview of the group was given three years before by Gilluly and Reeside. Baker revised the work and named the Kayenta Formation
in 1936. The work was revised again 1955 by Averitt and others. They assigned the Shurtz Sandstone Tongue (new) and Lamb Point Tongue (new) to the Navajo Sandstone
, and Cedar City Tongue (new) and Tenney Canyon Tongue (new) to the Kayenta Formation. In 1957 Harshbarger and others created an overview and revision that assigned the Moenave Formation
and divided the Wingate Sandstone
into newly the named Rock Point and Lukachukai members. The group's age was modified by Lewis and others in 1961 and the upper contact was revised by Phoenix in 1963. Poole and Stewart attempted to reduce the group's rank to a formation they called the Glen Canyon Sandstone in 1964 (change not recognized by the USGS). Areal extent limits were revised by Wilson and Stewart in 1967 and again by Green in 1974. Peterson and Pipiringos revised the upper contact and created an overview in 1979. In 1989 the age of the group was modified by Padian and separately by Dubiel (who also revised the lower contact). Condon modified the areal extent limits in 1992.
s, known from both skeletal remains and tracks. Dinosaur finds in the Wingate and Moenave formations are presently almost entirely tracks. The Kayenta Formation has a diverse skeletal fauna including the theropods "Syntarsus" kayentakatae
and Dilophosaurus
, the prosauropod Massospondylus
, an unnamed heterodontosaurid
, and the armored dinosaurs Scelidosaurus
and Scutellosaurus
. The Navajo Sandstone has body fossils of the theropod Segisaurus
and an Ammosaurus
-like prosauropod, and tracks.
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 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...
, 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...
, north west 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...
. It is sometimes called the Glen Canyon Sandstone in Colorado and Utah. There are four formations within the group. From oldest to youngest, these are the Wingate Sandstone
Wingate Sandstone
Wingate Sandstone is a geologic formation in the Glen Canyon Group that is spread across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah. This rock formation is particularly prominent in southeastern Utah, where it forms...
, Moenave Formation
Moenave Formation
The Moenave Formation is a Mesozoic geologic formation. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.-See also:* List of dinosaur-bearing rock formations...
, Kayenta Formation
Kayenta Formation
The Kayenta Formation is a geologic layer in the Glen Canyon Group that is spread across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah. This rock formation is particularly prominent in southeastern Utah, where it is seen in the...
, and Navajo Sandstone
Navajo Sandstone
Navajo Sandstone is a geologic formation in the Glen Canyon Group that is spread across the U.S. states of northern Arizona, northwest Colorado, and Utah; as part of the Colorado Plateau province of the United States...
. 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,...
and 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...
, this group of formations was laid down during 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...
and Early Jurassic
Early Jurassic
The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...
, with the Triassic-Jurassic boundary within the Wingate Sandstone. The top of the Glen Canyon Group is thought to date to the Toarcian
Toarcian
The Toarcian is, in the ICS' geologic timescale, an age or stage in the Early or Lower Jurassic. It spans the time between 183.0 Ma and 175.6 Ma...
stage of the Early Jurassic.
Asterisks (*) below indicate usage by the U.S. Geological Survey.
Subunits
Group rank (alphabetical):- Kayenta FormationKayenta FormationThe Kayenta Formation is a geologic layer in the Glen Canyon Group that is spread across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah. This rock formation is particularly prominent in southeastern Utah, where it is seen in the...
(AZ,CO*,UT*), - Moenave FormationMoenave FormationThe Moenave Formation is a Mesozoic geologic formation. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.-See also:* List of dinosaur-bearing rock formations...
(AZ*,NV*,UT*), - Navajo SandstoneNavajo SandstoneNavajo Sandstone is a geologic formation in the Glen Canyon Group that is spread across the U.S. states of northern Arizona, northwest Colorado, and Utah; as part of the Colorado Plateau province of the United States...
(AZ*,CO*,NM*,UT*), - Wingate SandstoneWingate SandstoneWingate Sandstone is a geologic formation in the Glen Canyon Group that is spread across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah. This rock formation is particularly prominent in southeastern Utah, where it forms...
(AZ*,CO*,NM*,UT*)
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 group. It was named by Gregory and Moore in 1931 for exposures in walls that form the Glen Canyon
Glen Canyon
Glen Canyon is a canyon that is located in southeastern and south central Utah and northwestern Arizona within the Vermilion Cliffs area. It was carved by the Colorado River....
of the Colorado River in Coconino County, Arizona
Coconino County, Arizona
-2010:Whereas according to the 2010 U.S. Census Bureau:*61.7% White*1.2% Black*27.3% Native American*1.4% Asian*0.1% Native Hawaiian or Pacific Islander*3.1% Two or more races*5.2% Other races*13.5% Hispanic or Latino -2000:...
and San Juan County, Utah
San Juan County, Utah
As of the current census of 2010, there were 14,746 people and 4,505 households. The racial and ethnic composition of the population was 50.4% Native American, 45.8% white, 0.3% Asian, 0.2% African American and 2.3% reporting two or more races...
. An overview of the group was given three years before by Gilluly and Reeside. Baker revised the work and named the Kayenta Formation
Kayenta Formation
The Kayenta Formation is a geologic layer in the Glen Canyon Group that is spread across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah. This rock formation is particularly prominent in southeastern Utah, where it is seen in the...
in 1936. The work was revised again 1955 by Averitt and others. They assigned the Shurtz Sandstone Tongue (new) and Lamb Point Tongue (new) to the Navajo Sandstone
Navajo Sandstone
Navajo Sandstone is a geologic formation in the Glen Canyon Group that is spread across the U.S. states of northern Arizona, northwest Colorado, and Utah; as part of the Colorado Plateau province of the United States...
, and Cedar City Tongue (new) and Tenney Canyon Tongue (new) to the Kayenta Formation. In 1957 Harshbarger and others created an overview and revision that assigned the Moenave Formation
Moenave Formation
The Moenave Formation is a Mesozoic geologic formation. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.-See also:* List of dinosaur-bearing rock formations...
and divided the Wingate Sandstone
Wingate Sandstone
Wingate Sandstone is a geologic formation in the Glen Canyon Group that is spread across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah. This rock formation is particularly prominent in southeastern Utah, where it forms...
into newly the named Rock Point and Lukachukai members. The group's age was modified by Lewis and others in 1961 and the upper contact was revised by Phoenix in 1963. Poole and Stewart attempted to reduce the group's rank to a formation they called the Glen Canyon Sandstone in 1964 (change not recognized by the USGS). Areal extent limits were revised by Wilson and Stewart in 1967 and again by Green in 1974. Peterson and Pipiringos revised the upper contact and created an overview in 1979. In 1989 the age of the group was modified by Padian and separately by Dubiel (who also revised the lower contact). Condon modified the areal extent limits in 1992.
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* - Green River 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...
* - 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....
* - Uinta Uplift*
Paleontology
Prehistoric animals from the various formations of the Glen Canyon Group include several types of dinosaurDinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s, known from both skeletal remains and tracks. Dinosaur finds in the Wingate and Moenave formations are presently almost entirely tracks. The Kayenta Formation has a diverse skeletal fauna including the theropods "Syntarsus" kayentakatae
Megapnosaurus
Megapnosaurus was a dinosaur of the theropod family Coelophysidae, formerly called Syntarsus , living during the Early Jurassic. It was renamed by American entomologist Dr. Michael Ivie , Polish Australian Dr...
and Dilophosaurus
Dilophosaurus
Dilophosaurus was a theropod dinosaur from the Sinemurian stage of the Early Jurassic Period, about 193 million years ago. The first specimens were described in 1954, but it was not until over a decade later that the genus received its current name...
, the prosauropod Massospondylus
Massospondylus
Massospondylus and ) is a genus of prosauropod dinosaur from the early Jurassic Period . It was described by Sir Richard Owen in 1854 from remains found in South Africa, and is thus one of the first dinosaurs to have been named...
, an unnamed heterodontosaurid
Heterodontosauridae
Heterodontosauridae is a family of early ornithischian dinosaurs that were likely among the most basal members of the group...
, and the armored dinosaurs Scelidosaurus
Scelidosaurus
Scelidosaurus is a genus of quadrupedal, lightly plated, herbivorous dinosaur about long. It lived during the Early Jurassic Period, during the Hettangian to Sinemurian stages around 199.6 to 194 million years ago. Its fossils have been found in both England and in Arizona, in the United...
and Scutellosaurus
Scutellosaurus
Scutellosaurus is a genus of herbivorous dinosaur that lived in North America around 200 to 196 million years ago, in the Early Jurassic times....
. The Navajo Sandstone has body fossils of the theropod Segisaurus
Segisaurus
Segisaurus is a genus of small coelophysoid theropod dinosaur, that measured approximately 1 metre in length. The only known specimen was discovered in 1933 in early Jurassic strata in Tsegi Canyon, Arizona, for which it was named. Segisaurus is the only dinosaur to have ever been excavated from...
and an Ammosaurus
Ammosaurus
Ammosaurus is a genus of sauropodomorph dinosaur from the Early and Middle Jurassic Period of North America. At 4 meters in length, it was small compared to some other members of its suborder, which included the largest animals ever to walk the Earth...
-like prosauropod, and tracks.
See also
Works cited
- GEOLEX database entry for Glen Canyon, USGS (viewed 19 March 2006)
- GEOLEX database Bibliographic References for Glen Canyon, USGS (viewed 19 March 2006)