The Carlile Shale is a
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...
age
Upper/Late Cretaceous series
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, especial ...
geologic
formation
Formation may refer to:
Linguistics
* Back-formation, the process of creating a new lexeme by removing or affixes
* Word formation, the creation of a new word by adding affixes
Mathematics and science
* Cave formation or speleothem, a secondar ...
in the central-western United States, including in the
Great Plains
The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, an ...
region of
Colorado
Colorado (, other variants) is a state in the 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 western edge of t ...
,
Kansas
Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...
,
Nebraska
Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the southwe ...
,
New Mexico
)
, population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano)
, seat = Santa Fe
, LargestCity = Albuquerque
, LargestMetro = Tiguex
, OfficialLang = None
, Languages = English, Spanish ( New Mexican), Navajo, Ker ...
,
North Dakota
North Dakota () is a U.S. state in the Upper Midwest, named after the Native Americans in the United States, indigenous Dakota people, Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north a ...
,
South Dakota
South Dakota (; Sioux language, Sioux: , ) is a U.S. state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota people, Lakota and Dakota peo ...
, and
Wyoming
Wyoming () is a U.S. state, state in the Mountain states, 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 south ...
.
Description
The formation is composed of marine deposits of the generally retreating phase (hemi-cycle) of the
Greenhorn cycle of 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 sea, ...
, which followed the advancing phase of the same cycle that formed the underlying
Graneros Shale
The Graneros Shale is a geologic formation in the United States identified in the Great Plains as well as New Mexico that dates to the Cenomanian Age of the Cretaceous Period. It is defined as the finely sandy argillaceous or clayey ''near-shore/ ...
and
Greenhorn Formation
The Greenhorn Limestone or Greenhorn Formation is a geologic formation in the Great Plains Region of the United States, dating to the Cenomanian and Turonian ages of the Late Cretaceous period. The formation gives its name to the Greenhorn cycle ...
. As such, the lithology progresses from open ocean chalky shale (with thin limestones) to increasing carbonaceous shale to near-shore sandstone. The contact between the Carlile Shale and the overlying
Niobrara Formation
The Niobrara Formation , also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late Cretaceous. It is compose ...
is marked by an
unconformity
An unconformity is a buried erosional or non-depositional 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 o ...
in much of the outcrop area, but where an unconformity is not discernible, the boundary is typically placed at the first resistant, fine-grained limestone bed at the base of the Niobrara Formation.
Fossil content
Upper Turonian series
plesiosaur
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia.
Plesiosaurs first appeared ...
remains are among the
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s that have been recovered from the strata of its Blue Hill Shale Member in Kansas.
[Jstor.org: "Probable plesiosaur remains from the Blue Hill Shale (Carlile Formation)" in Kansas"](_blank)
Kansas Academy of Science, 2009. The Carlile in eastern South Dakota contains shark teeth, fossil wood and leaves, and ammonites.
Reptiles
Crocodyliforms
Plesiosaurs
Squamates
Fish
Cartilaginous fish
History of investigation
The Carlile Shale was first named by
Grove Karl Gilbert
Grove Karl Gilbert (May 6, 1843 – May 1, 1918), known by the abbreviated name G. K. Gilbert in academic literature, was an American geologist.
Biography
Gilbert was born in Rochester, New York and graduated from the University of Rochester. D ...
for exposures at Carlile Spring, located about west of
Pueblo, Colorado
Pueblo () is a List of municipalities in Colorado#Home rule municipality, home rule municipality that is the county seat and the List of municipalities in Colorado, most populous municipality of Pueblo County, Colorado, Pueblo County, Colorado ...
. He described it as a medium gray shale, capped with limestone or sandstone, and assigned it to the Benton Group. By 1931,
William Walden Rubey
William Walden Rubey (December 19, 1898 – April 12, 1974) was an American geologist.
He was born in Moberly, Missouri. He attended the University of Missouri, and in 1920 he graduated with an A.B. degree. During the same year he married Susan El ...
and his coinvestigators had mapped it into
Kansas
Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...
and the
Black Hills
The Black Hills ( lkt, Ȟe Sápa; chy, Moʼȯhta-voʼhonáaeva; hid, awaxaawi shiibisha) is an isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, United States. Black Elk P ...
. Rubey also first assigned it to the Colorado Group. C.H. Dane assigned it to the
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, ...
in
New Mexico
)
, population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano)
, seat = Santa Fe
, LargestCity = Albuquerque
, LargestMetro = Tiguex
, OfficialLang = None
, Languages = English, Spanish ( New Mexican), Navajo, Ker ...
in 1948.
Gallery
See also
* Volcanic mineralization of the Greenhorn cycle:
**
Bentonite
Bentonite () is an absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-mon ...
, sedimentary volcanic ash (named for the original Graneros/Greenhorn/Carlile classification), generally showing some weathered iron stain in the Colorado Group
**
Pyrite
The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic Luster (mineralogy), lust ...
, precipitation of volcanic sulfuric acid with oceanic iron as FeS
2
**
Limonite
Limonite () is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·H2O, although this is not entirely accurate as the ratio of oxide to hydroxid ...
, pyrite in limestone weathered to HFeO
2 (
rust stain or
yellow ochre
Ochre ( ; , ), or ocher in American English, is a natural clay earth pigment, a mixture of ferric oxide and varying amounts of clay and sand. It ranges in colour from yellow to deep orange or brown. It is also the name of the colours produced ...
)
**
Selenite
Selenite may refer to:
Substances containing selenium
*A selenium-containing anion or ionic compound with the SeO32− anion:
**Selenite (ion), anion is a selenium oxoanion with the chemical formula SeO32−
***Selenous acid, the conjugate acid, w ...
, CaSO4 associated with Bentonite seams and ochre
*
Plesiosaur stratigraphic distribution
References
Shale formations of the United States
Turonian Stage
Cretaceous Colorado
Cretaceous Kansas
Cretaceous Nebraska
Cretaceous formations of New Mexico
Cretaceous geology of North Dakota
Cretaceous geology of South Dakota
Cretaceous geology of Wyoming
Upper Cretaceous Series of North America
Geologic formations of Colorado
Geologic formations of Kansas
Geologic formations of Nebraska
Geologic formations of North Dakota
Geologic formations of South Dakota
Geologic formations of Wyoming
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