
The Mesaverde Group is a
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...
stratigraphic
group
A group is a number of persons or things that are located, gathered, or classed together.
Groups of people
* Cultural group, a group whose members share the same cultural identity
* Ethnic group, a group whose members share the same ethnic ide ...
found in areas of
Colorado
Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...
,
New Mexico
)
, population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano)
, seat = Santa Fe, New Mexico, Santa Fe
, LargestCity = Albuquerque, New Mexico, Albuquerque
, LargestMetro = Albuquerque metropolitan area, Tiguex
, Offi ...
,
Utah
Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...
, and
Wyoming
Wyoming () is a state in the Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the sou ...
, in the
Western United States
The Western United States (also called the American West, the Far West, and the West) is the region comprising the westernmost states of the United States. As American settlement in the U.S. expanded westward, the meaning of the term ''the Wes ...
.
History
The Mesaverde Formation was first described by
W.H.Holmes in 1877 during the
Hayden Survey
Ferdinand Vandeveer Hayden (September 7, 1829 – December 22, 1887) was an American geologist noted for his pioneering surveying expeditions of the Rocky Mountains in the late 19th century. He was also a physician who served with the Union ...
. Holmes described the formation in the northern
San Juan Basin
The San Juan Basin is a geologic structural basin located near the Four Corners region of the Southwestern United States. The basin covers 7,500 square miles and resides in northwestern New Mexico, southwestern Colorado, and parts of Utah ...
as consisting of three units, which were a "Lower Escarpment" consisting of 40 m of ledge- and cliff-forming massive
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates ...
; a "Middle Coal Group" consisting of up to 300 m of thick slope-forming sandstone,
shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especia ...
,
marl, and
lignite; and an "Upper Escarpment" consisting of 60 m of ledge- and cliff-forming sandstone. A.J. Collier redesignated these units in 1919 as the
Point Lookout Sandstone
The Point Lookout Sandstone is a Cretaceous bedrock formation occurring in New Mexico and Colorado.
Description
The formation consists of two informal members. The lower is a sequence of thinly bedded sandstone and shale, while the upper is a m ...
, the
Menefee Formation
The Menefee Formation is a lower Campanian geologic formation found in Colorado and New Mexico, United States.
Description
The Menefee Formation consists of fluvial sandstone, shale, and coal. Based on ammonite biostratigraphy, the age of ...
, and the
Cliff House Sandstone
The Cliff House Sandstone is a late Campanian stratigraphic unit comprising sandstones in the western United States.
Description
The Cliff House Sandstone consists of fine grained white to orange calcareous sandstone. It intertongues with the ...
, and raised the Mesaverde Formation to group rank.
The group was later traced to the greater
Green River Basin
Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 nm. In subtractive color systems, used in painting and color printing, it is created by a combin ...
, the
Uintah and
Piceance Basin
The 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. The basi ...
s, the
Bighorn Basin
The Bighorn Basin is a plateau region and intermontane basin, approximately 100 miles (160 km) wide, in north-central Wyoming in the United States. It is bounded by the Absaroka Range on the west, the Pryor Mountains on the north, the Bigh ...
, the
Front Range
The Front Range is a mountain range of the Southern Rocky Mountains of North America located in the central portion of the U.S. State of Colorado, and southeastern portion of the U.S. State of Wyoming. It is the first mountain range encountere ...
, the
Zuni Basin
The Zuni (Zuñi) River is a tributary of the Little Colorado River in the southwestern United States. It has its origin in Cibola County, New Mexico, in the Zuñi Mountains at the Continental Divide. The river flows off the western slopes of the ...
, the
Wasatch Plateau
The Wasatch Plateau is a plateau located southeast of the southernmost part of the Wasatch Range in central Utah. It is a part of the Colorado Plateau.
Geography
The plateau has an elevation of and includes an area of . Its highest point in th ...
,
Wind River Basin
The Wind River Basin or Shoshone Basin is a semi-arid intermontane foreland basin in central Wyoming, United States. It is bounded by Laramide uplifts on all sides. On the west is the Wind River Range and on the North are the Absaroka Range and ...
, Washakie Basin, and the
Powder River Basin
The Powder River Basin is a geologic structural basin in southeast Montana and northeast Wyoming, about east to west and north to south, known for its extensive coal reserves. The former hunting grounds of the Oglala Lakota, the area is very ...
. It is spectacularly exposed along the
Book Cliffs
The Book Cliffs are a series of desert mountains and cliffs in western Colorado and eastern Utah in the western United States. They are so named because the cliffs of Cretaceous sandstone that cap many of the south-facing buttes appear similar ...
of eastern Utah and western Colorado. With the recognition of the vast extent of the group, the group has been divided into formations by region, with the original Point Lookout Sandstone, Menefee Formation, and Cliff House Sandstone being restricted largely to the San Juan Basin and the
Madrid, New Mexico
Madrid (/ˈmædrɪd/, Spanish: aˈðɾið is a census-designated place (CDP) in Santa Fe County, New Mexico, United States. It is part of the Santa Fe, New Mexico Metropolitan Statistical Area. The population was 149 at the 2000 census and 204 i ...
area.
Geology
The group is a single
regression
Regression or regressions may refer to:
Science
* Marine regression, coastal advance due to falling sea level, the opposite of marine transgression
* Regression (medicine), a characteristic of diseases to express lighter symptoms or less extent ( ...
-
transgression
Transgression may refer to:
Legal, religious and social
*Sin, a violation of God's Ten Commandments or other elements of God's moral law
*Crime, legal transgression, usually created by a violation of social or economic boundary
**In civil law ju ...
sequence in its type location in the
San Juan Basin
The San Juan Basin is a geologic structural basin located near the Four Corners region of the Southwestern United States. The basin covers 7,500 square miles and resides in northwestern New Mexico, southwestern Colorado, and parts of Utah ...
, dividing the older marine
Mancos Shale
The Mancos Shale or Mancos Group is a Late Cretaceous (Upper Cretaceous) geologic formation of the Western United States.
The Mancos Shale was first described by Cross and Purington in 1899 and was named for exposures near the town of Mancos ...
and younger
Lewis Shale
The Lewis Shale is a geologic formation in the Western United States. It preserves fossils dating back to the Campanian to Maastrichtian stages of the late Cretaceous period.
Description
The Lewis Shale is an olive-gray marine shale with some ...
deposited in the
Western Interior Seaway
The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, and the Western Interior Sea) was a large inland sea that split the continent of North America into two landmasses. The ancient se ...
. The
Point Lookout Sandstone
The Point Lookout Sandstone is a Cretaceous bedrock formation occurring in New Mexico and Colorado.
Description
The formation consists of two informal members. The lower is a sequence of thinly bedded sandstone and shale, while the upper is a m ...
represents the regression, the
Menefee Formation
The Menefee Formation is a lower Campanian geologic formation found in Colorado and New Mexico, United States.
Description
The Menefee Formation consists of fluvial sandstone, shale, and coal. Based on ammonite biostratigraphy, the age of ...
the subsequent fluvial delta deposits, and the
Cliff House Sandstone
The Cliff House Sandstone is a late Campanian stratigraphic unit comprising sandstones in the western United States.
Description
The Cliff House Sandstone consists of fine grained white to orange calcareous sandstone. It intertongues with the ...
the return of the sea. In other locations, such as along the Book Cliffs, the picture is more complicated, with multiple regression-transgression sequences from tectonic activity along the
Sevier
Sevier ( ) is an unincorporated community in southwestern Sevier County, Utah, United States. It lies in the valley of the Sevier River along U.S. Route 89 southwest of the city of Richfield, the county seat of Sevier County. Its elevation is ...
mountain front. In the Cody area, the group is a simple regression sequence and remains at formation rank. Here the group is described as interbedded light gray sandstone and gray shale in the upper part; massive, light-buff, ledge-forming sandstone containing thin lenticular coal beds in the lower part.
Formations
northern Piceance Basin:
*
Williams Fork Formation
The Williams Fork Formation is a Campanian ( Edmontonian) geologic formation of the Mesaverde Group in Colorado. Dinosaur remains are among the fossils that have been recovered from the formation, most notably '' Pentaceratops sternbergii'',. Othe ...
*
Iles Formation
The Iles Formation is a Mesozoic geologic Formation (geology), formation. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.Weishampel et al., 2004, pp.517- ...
southwestern Piceance Basin:
* Hunter Canyon Formation
* Mount Garfield Formation
Powder River Basin:
* Teapot Sandstone
* Parkman Sandstone
Northern San Juan Basin:
* Point Lookout Sandstone
* Menefee Formation
* Cliff House Sandstone
Southern San Juan Basin and southern New Mexico:
* Point Lookout Sandstone
*
Crevasse Canyon Formation
The Crevasse Canyon Formation is a coal-bearing Cretaceous geologic formation in New Mexico and Arizona.
Description
The formation is divided into three members, in ascending stratigraphic order: ''Dilco Coal Member'', ''Dalton Sandstone Memb ...
*
Gallup Sandstone
The Gallup Sandstone is a geologic formation in the Gallup-Zuni basin of New Mexico. It preserves fossils dating back to the late Cretaceous period.
Description
The formation consists of uniform, very well sorted, fine-grained pink to buff sands ...
Uintah Basin:
* Tuscher Formation
* Farrer Formation
*
Neslen Formation
The Neslen Formation is a geologic formation in Utah. It preserves fossils dating back to the Cretaceous period. It has been exploited for coal. The Kaiparowits Formation is closely associated.
Only two specimens have been reported from the form ...
* Sego Sandstone
*
Price River Formation
The Price River Formation is a geologic formation in Utah. It preserves fossils dating back to the Cretaceous period. The Price River Formation is approximately thick at its type locality ( Price River Canyon) and consists
of cliff-forming sands ...
*
Castlegate Sandstone
The Castlegate Sandstone is a Mesozoic geologic formation in the United States. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.Weishampel, et al. (2004) ...
*
Blackhawk Formation
The Blackhawk Formation is a geological formation in east-central Utah, USA. It was named for the former town of Blackhawk on the east side of the Wastach Plateau, Carbon County. The formation is composed of mostly light-brown, light-gray and bro ...
* Star Point Sandstone
Washakie Basin:
*
Almond Formation
The Almond Formation is a geological Formation (geology), formation of Late Cretaceous (Late Campanian-Early Maastrichtian) Geochronology, age in Wyoming. It was deposited in marsh, river delta, deltaic, lagoonal, estuary, estuarine, and shallow ...
* Ericson Sandstone
*
Rock Springs Formation
The Rock Springs Formation is a geologic formation in Wyoming. It preserves fossils dating back to the Cretaceous period.
See also
* List of fossiliferous stratigraphic units in Wyoming
* Paleontology in Wyoming
Paleontology in Wyoming include ...
* Blair Formation
Fossils
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
remains are among the fossils that have been recovered from the group, although none have yet been referred to a specific
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...
. ''
Deinosuchus
''Deinosuchus'' () is an extinct genus of alligatoroid crocodilian, related to modern alligators and caimans, that lived 82 to 73 million years ago (Ma), during the late Cretaceous period. The name translates as "terrible crocodile" and ...
'' has also been reported from Mesaverde outcrops in Wyoming.
See also
*
List of dinosaur-bearing rock formations
This list of dinosaur-bearing rock formations is a list of geologic formations in which dinosaur fossils have been documented.
Containing body fossils
* List of stratigraphic units with dinosaur body fossils
** List of stratigraphic units with f ...
**
List of stratigraphic units with indeterminate dinosaur fossils
This list of stratigraphic units with indeterminate dinosaur fossils includes stratigraphic units of formation rank or higher that have produced dinosaur body fossils, although none of these remains have been referred to a specific genus in the sci ...
Footnotes
References
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* {{cite book , editor-last1=Weishampel , editor-first1=David B. , editor-last2=Dodson , editor-first2=Peter , editor-last3=Osmólska , editor-first3=Halszka , year=2004 , title=The Dinosauria , edition=2nd , location=Berkeley , publisher=University of California Press , isbn=0-520-24209-2
Cretaceous formations of New Mexico
Cretaceous geology of Utah
Cretaceous geology of Wyoming
Geologic groups of New Mexico
Upper Cretaceous Series of North America