The Pierre Shale is a
geologic formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...
or series in the
Upper 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'', the ...
which occurs east of the
Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
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 ...
, from
Pembina Valley
The Pembina Valley (french: Vallée-de-la-Pembina) is an informal geographic region of the Canadian province of Manitoba. It is named for its major geographical feature, the Pembina Valley, which runs through the southwestern part of the region.
...
in
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
to
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 ...
.
The Pierre Shale was described by
Meek
Meekness is an attribute of human nature and behavior that has been defined as an amalgam of righteousness, inner humility, and patience.
Meekness has been contrasted with humility alone insomuch as humility simply refers to an attitude towards o ...
and
Hayden Hayden may refer to:
Places Inhabited places in the United States
*Hayden, Alabama
*Hayden, Arizona
*Hayden's Ferry, former name of Tempe, Arizona
*Hayden, California, former name of Hayden Hill, California
*Hayden, Colorado
*Hayden, Idaho
*Hayden ...
in 1862 in the Proceedings of the Academy of Sciences (Philadelphia). They described it as a dark-gray
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 ...
, fossiliferous, with veins and seams of
gypsum
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. ...
, and
concretions
A concretion is a hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular ...
of
iron oxide
Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. All are black magnetic solids. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of whic ...
. The Pierre Shale is about 700 feet (210m) thick at the type locality. It overlies the
Niobrara division and underlies the Fox Hills beds.
It was named for an occurrence near
Fort Pierre on the
Missouri River in
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 ...
.
The Pierre Shale is of marine origin and was 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 sea, ...
. It is correlative with other marine shales that occur farther west, such as the
Bearpaw Shale
The Bearpaw Formation, also called the Bearpaw Shale, is a geologic formation of Late Cretaceous (Campanian) age. It outcrops in the U.S. state of Montana, as well as the Canadian provinces of Alberta and Saskatchewan, and was named for the Bear ...
,
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 the
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 t ...
.
It correlates with the
Lea Park Formation
The Lea Park Formation is a stratigraphical unit of Late Cretaceous age in the Western Canadian Sedimentary Basin, Canada.
It takes the name from the settlement of Lea Park, Alberta, located north-west of Lloydminster on the banks of the North ...
in
central Alberta
Central Alberta is a region located in the Canadian province of Alberta.
Central Alberta is the most densely populated rural area in the province. Agriculture and energy are important to the area's economy.
Geography
Central Alberta is bordere ...
.
The Pierre is overlain by marginal marine deposits of the
Fox Hills Formation
The Fox Hills Formation is a Cretaceous geologic Formation (geology), formation in the northwestern Great Plains of North America. It is present from Alberta on the north to Colorado in the south.
Fossil remains of dinosaurs, including tyrannos ...
.
Most of the formation was deposited in the
Campanian
The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campanian s ...
Age
Age or AGE may refer to:
Time and its effects
* Age, the amount of time someone or something has been alive or has existed
** East Asian age reckoning, an Asian system of marking age starting at 1
* Ageing or aging, the process of becoming older ...
of the
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'', the ...
. However, the discovery of fossils of ''
Baculites baculus'' Meek and Hayden in the uppermost beds of the Pierre Shale in the
Raton, New Mexico
Raton ( ) is a city and the county seat of Colfax County, New Mexico, Colfax County in northeastern New Mexico. The city is located just south of Raton Pass. The city is also located about 6.5 miles south of the New Mexico–Colorado border and 85 ...
area show that deposition continued here into the early
Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...
.
Mineral resources
The Pierre Shale is the host formation for commercial
petroleum
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crud ...
deposits in the Florence and Canon City fields in
Fremont County, Colorado
Fremont County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 48,939. The county seat is Cañon City. The county is named for 19th-century explorer and presidential candidate John C. Frémont.
Fre ...
, and the
Boulder Oil Field in
Boulder County, Colorado
Boulder County is a county located in the U.S. state of Colorado of the United States. As of the 2020 census, the population was 330,758. The most populous municipality in the county and the county seat is Boulder.
Boulder County comprises th ...
. More recently, natural gas has been extracted in the
Raton Basin
Raton or Ratón (Spanish for "mouse") may refer to:
Places:
* Raton Basin, a geologic structural basin in southern Colorado and northern New Mexico
* Raton, New Mexico, the county seat of Colfax County, New Mexico
** Raton Downtown Historic Dis ...
in southern
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 ...
. The shale formation is usually too impermeable for hydrocarbon extraction, but produces in areas where it is naturally fractured or
fractured by artificial means.
Paleofauna
Reptiles
Dinosaurs
Mosasaurs
Plesiosaurs
Turtles
Fish
Bony fish
Cartilaginous fish
Marine vertebrates
* ''
Gillicus
''Gillicus'' was a relatively small, 2-metre long ichthyodectiform fish that lived in the Western Interior Seaway, in what is now central North America, during the Late Cretaceous.
Description
Like its larger relative, ''Ichthyodectes ctenodon ...
''
* ''
Pseudocorax
''Pseudocorax'' is an extinct genus of mackerel sharks that lived during the Late Cretaceous. It contains six valid species that have been found in Europe, the Middle East, North Africa, and North America. It was formerly assigned to the family ...
''
* ''
Carcharias
''Carcharias'' is a genus of sand tiger sharks belonging to the family Odontaspididae. Once bearing many prehistoric species, all have gone extinct with the exception of the critically endangered sand tiger shark.
Description
''Carcharias'' ar ...
''
Invertebrates
Annelids
Arthropods
Bivalves
Brachiopods
Cephalopods
Echinoderms
Gastropods
Scaphopods
References
{{Authority control
Upper Cretaceous Series of North America
Cretaceous Alberta
Cretaceous Colorado
Cretaceous Kansas
Cretaceous Montana
Cretaceous geology of Nebraska
Cretaceous formations of New Mexico
Cretaceous geology of South Dakota
Cretaceous geology of Wyoming
Campanian Stage
Shale formations of the United States
Shale formations
Oil-bearing shales in Canada
Oil-bearing shales in the United States
Great Plains