Coteau du Missouri
Encyclopedia
Plateau
In geology and earth science, a plateau , also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau...
that stretches along the eastern side of the valley of the Missouri River
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...
in central North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
and north-central South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
in the United States. This physiographic region of Saskatchewan and Alberta is classified as the uplands Missouri Coteau which is a part of the Great Plains Province or Alberta Plateau Region which extends across the south east corner of the province of Saskatchewan
Saskatchewan
Saskatchewan is a prairie province in Canada, which has an area of . Saskatchewan is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, and on the south by the U.S. states of Montana and North Dakota....
as well as the south west corner of the province of Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
. Historically, in Canada the area was known as the Palliser's Triangle
Palliser's Triangle
Palliser's Triangle, or the Palliser Triangle, is a largely semi-arid steppe region in the Prairie Provinces of Western Canada that was determined to be unsuitable for agriculture because of its unfavourable climate. The soil in this area is dark brown or black in color and is very nutrient-rich....
regarded as an extension of the Great American Desert and unsuitable for agriculture and thus designated by Canadian geographer
Geographer
A geographer is a scholar whose area of study is geography, the study of Earth's natural environment and human society.Although geographers are historically known as people who make maps, map making is actually the field of study of cartography, a subset of geography...
and explorer John Palliser
John Palliser
John Palliser was an Irish-born geographer and explorer. Born in Dublin, Ireland, he was the son of Colonel Wray Palliser and a brother of Major Sir William Palliser , all descendants of Dr William Palliser, Archbishop of Cashel .From 1839 to 1863, Palliser served in the Waterford Militia,...
. The terrain of the Missouri Coteau features low hummocky, undulating, rolling hills, potholes, and grasslands.
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Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
the plateau is part of the extended plateau of the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
in the Dakotas, and is separated from the main plateau to the west by the Missouri River Trench
Missouri River Trench
The Missouri River Trench is the geological name applied to the broad valley of the Missouri River as it flows southward through North Dakota and South Dakota in the United States....
. The plateau is underlain by Pierre shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
covered with hardened deposits from repeated glaciations
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
. The plateau also contains deposits of lignite
Lignite
Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad,is a soft brown fuel with characteristics that put it somewhere between coal and peat...
, mirabilite
Mirabilite
Mirabilite, also known as Glauber's salt, is a hydrous sodium sulfate mineral with the chemical formula Na2SO4·10H2O. It is a vitreous, colorless to white monoclinic mineral which forms as an evaporite from sodium sulfate bearing brines. It is found around saline springs and along saline playa lakes...
(sodium sulfate
Sodium sulfate
Sodium sulfate is the sodium salt of sulfuric acid. When anhydrous, it is a white crystalline solid of formula Na2SO4 known as the mineral thenardite; the decahydrate Na2SO4·10H2O has been known as Glauber's salt or, historically, sal mirabilis since the 17th century. Another solid is the...
), and bentonite
Bentonite
Bentonite is an absorbent aluminium phyllosilicate, essentially impure clay consisting mostly of montmorillonite. There are different types of bentonite, each named after the respective dominant element, such as potassium , sodium , calcium , and aluminum . Experts debate a number of nomenclatorial...
. While subjected to continental glaciation, it was north and west of the Driftless Area, an area which escaped glaciation.
The plateau is poorly drained and is interspersed with glacial kettle lakes. It is transversed by several broad sag
Sag (geology)
In geology a sag, or trough, is a depressed, persistent, low area; the opposite of an arch, or ridge, a raised, persistent, high area. The terms sag and arch were used historically to describe very large features, for example, characterizing North America as two arches with a sag between them.Also,...
s marking the ancient stream valleys of the eastern continuations of the Grand
Grand River (South Dakota)
The Grand River is a tributary of the Missouri River in North Dakota and South Dakota in the United States. The length of the combined branch is 110 mi...
, Moreau
Moreau River
The Moreau River is a tributary of the Missouri River, approximately 200 mi long, in South Dakota in the United States.It rises in two forks in northwestern South Dakota, in the Badlands of Harding County. The North Fork rises approximately 10 mi northeast of Crow Buttes...
, Cheyenne
Cheyenne River
The Cheyenne River is a tributary of the Missouri River in the U.S. states of Wyoming and South Dakota. It is approximately 295 mi long and drains an area of...
, Cheyenne River
Cheyenne River
The Cheyenne River is a tributary of the Missouri River in the U.S. states of Wyoming and South Dakota. It is approximately 295 mi long and drains an area of...
, Bad
Bad River (South Dakota)
The Bad River is a tributary of the Missouri River, approximately long, in central South Dakota in the United States.The river is formed at Philip, South Dakota, by the confluence of its North and South forks...
, and White
White River (South Dakota)
The White River is a Missouri River tributary that flows through the U.S. states of Nebraska and South Dakota. The name stems from the water's white-gray color, a function of eroded sand, clay, and volcanic ash carried by the river...
rivers.
To the east of the plateau, the lowland valley of the James River
James River (Dakotas)
The James River is a tributary of the Missouri River, approximately 710 mi long, draning an area of in the U.S. states of North Dakota and South Dakota...
was formed by the lobe of the most recent ice age
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...
, separating the plateau from the Coteau des Prairies
Coteau des Prairies
The Coteau des Prairies is a plateau approximately 200 miles in length and 100 miles in width , rising from the prairie flatlands in eastern South Dakota, southwestern Minnesota, and northwestern Iowa in the United States...
to the east.
Agriculturally
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
the plateau is a grain and livestock region.
See also
- Coteau des PrairiesCoteau des PrairiesThe Coteau des Prairies is a plateau approximately 200 miles in length and 100 miles in width , rising from the prairie flatlands in eastern South Dakota, southwestern Minnesota, and northwestern Iowa in the United States...
- Geography of SaskatchewanGeography of SaskatchewanThe geography of Saskatchewan , is unique among the provinces and territories of Canada in some respects. It is one of only two landlocked regions and it is the only region whose borders are not based on natural features like lakes, rivers or drainage divides...
- Cypress Hills Interprovincial ParkCypress Hills Interprovincial ParkCypress Hills Interprovincial Park is an interprovincial park straddling the southern Alberta-Saskatchewan border, located southeast of Medicine Hat...
- Cypress Hills (Canada)
- List of highest points of Canadian provinces and territories