The Interior Plains is a vast

physiographic region Physiographic regions are a means of defining Earth's landforms into independently distinct, mutually exclusive areas, independent of political boundaries. It is based upon the classic three-tiered approach by Nevin M. Fenneman in 1916, that separ ...

that spreads across the Laurentian craton of central

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, extending along the east flank 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 great-circle distance, straight-line distance from the northernmost part of Western Can ...

from the

Gulf Coast The Gulf Coast of the United States, also known as the Gulf South or the South Coast, is the coastline along the Southern United States where they meet the Gulf of Mexico. The coastal states that have a shoreline on the Gulf of Mexico are Tex ...

region to the

Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

Beaufort Sea The Beaufort Sea ( ; ) is a marginal sea of the Arctic Ocean, located north of the Northwest Territories, Yukon, and Alaska, and west of the Canadian Arctic Archipelago. The sea is named after Sir Francis Beaufort, a Hydrography, hydrographer. T ...

. In

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, it encompasses the

Canadian Prairies The Canadian Prairies (usually referred to as simply the Prairies in Canada) is a region in Western Canada. It includes the Canadian portion of the Great Plains and the Prairie provinces, namely Alberta, Saskatchewan, and Manitoba. These provin ...

separating the

Canadian Rockies The Canadian Rockies () or Canadian Rocky Mountains, comprising both the Alberta Rockies and the British Columbian Rockies, is the Canadian segment of the North American Rocky Mountains. It is the easternmost part of the Canadian Cordillera, w ...

from the

Canadian Shield The Canadian Shield ( ), also called the Laurentian Shield or the Laurentian Plateau, is a geologic shield, a large area of exposed Precambrian igneous and high-grade metamorphic rocks. It forms the North American Craton (or Laurentia), th ...

, as well as the Boreal Plains and Taiga Plains east of the Mackenzie and Richardson Mountains; while in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, it includes the

Great Plains The Great Plains is a broad expanse of plain, flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include th ...

of the

West West is one of the four cardinal directions or points of the compass. It is the opposite direction from east and is the direction in which the Sun sets on the Earth. Etymology The word "west" is a Germanic word passed into some Romance langu ...

Midwest The Midwestern United States (also referred to as the Midwest, the Heartland or the American Midwest) is one of the four census regions defined by the United States Census Bureau. It occupies the northern central part of the United States. It ...

and the

tallgrass prairie The tallgrass prairie is an ecosystem native to central North America. Historically, natural and Historical ecology#Anthropogenic fire, anthropogenic fire, as well as grazing by large mammals (primarily bison) provided periodic disturbances to th ...

region to the south of the

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, H ...

extending east to the

Appalachian Plateau The Appalachian Plateau is a series of rugged dissected plateaus located on the western side of the Appalachian Mountains. The Appalachian Mountains are a range that run from Nova Scotia in Canada to Alabama in the United States. The Appalachi ...

region.

Geologic history

A series of tectonic plate collisions in the crust that formed the center of the North American continent laid the groundwork for the modern-day interior plains. Mountain building and erosion around the plains as well as flooding from inland seas provided sediments that make up the rock strata of the interior plains.

Proterozoic Eon (2500 to 539 million years ago)

Between 2.0 and 1.8 billion years ago the Hearne-Rae, Superior, and Wyoming cratons were sutured together to form the North American craton,

Laurentia Laurentia or the North American craton is a large continental craton that forms the Geology of North America, ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of ...

, in an event called the

Trans-Hudson Orogeny The Trans-Hudson orogeny or Trans-Hudsonian orogeny was the major mountain building event (orogeny) that formed the Precambrian Canadian Shield and the North American Craton (also called Laurentia), forging the initial North American conti ...

(THO). This event was like the

Indian Plate The Indian plate (or India plate) is or was a minor tectonic plate straddling the equator in the Eastern Hemisphere. Originally a part of the ancient continent of Gondwana, the Indian plate broke away from the other fragments of Gondwana an ...

colliding with the Eurasian Plate, which formed the

Himalayas The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than list of h ...

. After initial collisions during the THO, tectonic activity at the edges of the four main cratons sparked

mountain building Mountain formation occurs due to a variety of geological processes associated with large-scale movements of the Earth's crust (List of tectonic plates, tectonic plates). Fold (geology), Folding, Fault (geology), faulting, Volcano, volcanic acti ...

. The interior of Laurentia remained relatively flat and became a basin for eroded sediment from mountains at the beginning of the current time period, the

Phanerozoic Eon The Phanerozoic is the current and the latest of the four geologic eons in the Earth's geologic time scale, covering the time period from 538.8 million years ago to the present. It is the eon during which abundant animal and plant life has ...

. The only remaining outcrops from this orogeny in the interior plains are in the Black Hills of South Dakota. The sediments that formed the Black Hills were

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

and different types of

igneous rocks Igneous rock ( ), or magmatic rock, is one of the three main Rock (geology)#Classification, rock types, the others being sedimentary rock, sedimentary and metamorphic rock, metamorphic. Igneous rocks are formed through the cooling and solidifi ...

, which make up the basement of bedrock in central North America. However, much of the Black Hills sediment has been

metamorphosed Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...

and deformed, so it is uncertain what the conditions were like at the time of their formation.

Paleozoic Era (539 to 252 million years ago)

This period has a large importance in Earth's history as it saw the Cambrian explosion and Permian extinction. When global sea level rose and continents became partially submerged, the oceans had an explosion of complex life, which was the first time an event like this occurred on Earth. However, the center of Laurentia remained above sea level and as the continent moved east towards other supercontinents like

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

, the

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions associated with the mountain range, and its surrounding terrain ...

began to form around 400 MYA. This coincided with the formation of

Pangea Pangaea or Pangea ( ) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia (continent), Siberia during the Carboniferous period ...

around 300 MYA, when the Appalachians were at their peak height. The central plains of Laurentia were subjected to deposition of eroded sediment from these mountains. The oldest sediments from this period are

felsic In geology, felsic is a grammatical modifier, modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz.Marshak, Stephen, 2009, ''Essentials of Geology,'' W. W. Norton & Company, 3rd ed. It is contrasted ...

igneous rocks and granite that have since been metamorphosed, while the younger sediments are made up of

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

, and

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

. Sediments deposited in the interior plains from this era are currently buried deep beneath the surface where they are difficult to study.

Mesozoic Era (252 to 66 million years ago)

Around 220 MYA, the supercontinent Pangea broke apart, and the North American continent began to move west and isolate itself. For much of this period the interior plains were covered by inland seas. During the

Jurassic period The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. The Jurassic constitutes the second and m ...

, the Sundance Sea formed along the western coast of the North American continent and extended from northern

to the interior plains, covering parts of

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

, and

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, 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 Dakota people, Dakota Sioux ...

Coquina Coquina () is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically sorted fragments of mollusks, trilobites, brachiopods, or other invertebrates. The term ''coquina'' comes from the S ...

and sandstone layers from marine deposition were deposited on top of rock layers from the Paleozoic Era. During the

Cretaceous period The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 77.1 million years, it is the ninth and longest geologi ...

, another inland sea called the

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, or the Western Interior Sea) was a large inland sea (geology), inland sea that existed roughly over the present-day Great Plains of ...

was formed. This body of water extended from present-day

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

to the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

and covered almost all the interior plains west of the current boundary of the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

. Limestone-shale couplets, as well as

carbonate A carbonate is a salt of carbonic acid, (), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate group ...

layers, are commonly found in sedimentary deposits from this inland sea. Towards the end of this period, the inland seas began to drain due to uplift from the formation of the

Cenozoic Era (66 million years ago to Present Day)

The

Laramide Orogeny The Laramide orogeny was a time period of mountain building in western North America, which started in the Late Cretaceous, 80 to 70 million years ago, and ended 55 to 35 million years ago. The exact duration and ages of beginning and end of the o ...

event was when the western

Cordillera A cordillera is a chain or network of mountain ranges, such as those in the west coast of the Americas. The term is borrowed from Spanish, where the word comes from , a diminutive of ('rope'). The term is most commonly used in physical geogra ...

was formed due to the flat-slab subduction of the Farallon Plate under the North American Plate. This created the frontal range of the Rockies from

through

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

. The outcrops seen at the surface of the Rockies are made up of sandstone, granite, and limestone; as well as metamorphic rocks uplifted from the

Proterozoic The Proterozoic ( ) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, and is the longest eon of Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozo ...

Period. The interior plains have remained relatively flat during this period and recent sedimentation is from erosion of the newly formed Rocky Mountains as well as continued erosion from Appalachia. In general, Rocky Mountain sediment is deposited on the plains west of the Mississippi River, and Appalachian sediment is deposited to the east of the Mississippi River.

Glacial history

2.6 million years ago at the start of the

Pleistocene Epoch The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

, the Laurentide Ice Sheet began to spread southwards to cover North America down to the northern Great Plains on the western side of the Interior Plains and down into most of Minnesota and Wisconsin. The Laurentide Ice Sheet had a large influence on the morphology of the Interior Plains during the end of the Pleistocene. During the retreat, the Laurentide scoured numerous pockets of sediment. Upon the plate's melting, those pockets were filled, resulting in the kettle lakes. The Great Lakes and both

Great Slave Lake Great Slave Lake is the second-largest lake in the Northwest Territories, Canada (after Great Bear Lake), List of lakes by depth, the deepest lake in North America at , and the List of lakes by area, tenth-largest lake in the world by area. It ...

and Great Bear Lake of Canada were formed by the Laurentide. During the retreat, the Laurentide gouged and filled the glacial paleolake McConnell in northern Canada. As the region uplifted and rebounded isostatically from the mass of the ice sheet, paleolake McConnell was split into Great Slave Lake and Great Bear Lake. Great Slave Lake's basin formed under the 4-kilometer thick Keewatin Dome that today is the deepest lake in North America. A vast amount of smaller lakes were formed as well and serve an integral part of ethos in the surrounding regions. For example, Minnesota is often referred to as “the Land of 10,000 Lakes” due to the number and widespread recreational use of the state's lakes. Much of the loess distributed within the Interior Plains has its origin in glaciers. In glaciated conditions, sand and silt-laden meltwater originating from alpine glaciers in the Rocky Mountains generated alluvial deposits at their base. This alluvium was then distributed throughout the Interior Plains by strong winds.

Sediment transport

Sediment transport within the Interior Plains occurs primarily by aeolian and

fluvial processes In geography and geology, fluvial sediment processes or fluvial sediment transport are associated with rivers and streams and the Deposition (geology), deposits and landforms created by sediments. It can result in the formation of ripple marks, r ...

. Due to climate change, the average temperature of the Interior Plains is increasing and the region is becoming more arid. Because of the increase in rainstorm intensity, rain-driven erosion will grow as a factor of soil erosion in the Interior Plains.

Fluvial processes

Civil engineering projects have altered the fluvial geomorphology of the Interior Plains. Normal sediment transport by river and channel systems is interrupted by river-blocking structures such as dams and flow regulators. Before 1900, the estimated annual sediment transport by the Mississippi River to the Gulf of Mexico was 400 million tons. However, in the early 20th century, engineering projects including dams were created on the Missouri River, meander cutoffs, river training, bank revetments, and soil erosion control have reduced the annual transport rate to between 100 and 150 million tons of sediment per year. The artificial structures trap suspended sediment from traveling as it would in an un-engineered river.

Aeolian processes

While average annual temperatures vary significantly between the northern and southern portions of the Interior Plains, the climate is characterized by susceptibility to droughts due to generally low annual precipitation. Due to a warm climate and

evapotranspiration Evapotranspiration (ET) refers to the combined processes which move water from the Earth's surface (open water and ice surfaces, bare soil and vegetation) into the Atmosphere of Earth, atmosphere. It covers both water evaporation (movement of w ...

rates surpassing precipitation rates, the southern Interior Plains are highly susceptible to droughts and

soil erosion Soil erosion is the denudation or wearing away of the Topsoil, upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, Atmosphere of Ea ...

. A significant feature of aeolian erosion in the Interior Plains is the ubiquitous

loess A loess (, ; from ) is a clastic rock, clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. Ten percent of Earth's land area is covered by loesses or similar deposition (geology), deposits. A loess ...

deposits. The deposits were placed by winds during the

Pleistocene epoch The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

. The Nebraska Sand Dunes are an example of the sand and loess during the epoch. These dunes were formed during the Pleistocene by Northwesterly winds depositing alluvial silt and sand. That loess is so prevalent in the Interior Plains is evidence of significant aeolian erosion, as deposits are generally accumulations of wind-blown dust. Loess Hills 0628

Following

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

, wheat farming in the fertile loess soil of the Interior Plains swelled. The expansion of farmland eliminated many prairies containing soil-stabilizing grasses. While droughts in the region were common, during the following drought, aeolian soil erosion was exacerbated by the reduced soil-holding prairie grasses. Dust storms eroded hundreds of millions of tons of topsoil, causing dust storms for months in the historical region known as the

Dust Bowl The Dust Bowl was a period of severe dust storms that greatly damaged the ecology and agriculture of the American and Canadian prairies during the 1930s. The phenomenon was caused by a combination of natural factors (severe drought) and hum ...

. On May 12, 1934, alone, an estimated 200 million tons of wind-eroded topsoil were transported to the Atlantic Ocean. In response to the rapid aeolian erosion, soil preservation methods were implemented. In the years following the Dust Bowl, of shelterbelt were planted by the

Works Progress Administration The Works Progress Administration (WPA; from 1935 to 1939, then known as the Work Projects Administration from 1939 to 1943) was an American New Deal agency that employed millions of jobseekers (mostly men who were not formally educated) to car ...

to reduce wind intensity.

Current land use

Grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...

and

shrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominance (ecology), dominated by shrubs, often also including grasses, herbaceous plant, herbs, and geophytes. Shrubland may either occur naturally o ...

make up the largest portion of the Interior Plains within the United States, at 44.4 percent. The western margin is mainly shortgrass prairie dominated by blue grama and buffalograss. Prairies on the eastern side of the Interior Plains are dominated by tall grass varieties including

big bluestem ''Andropogon gerardi'', commonly known as big bluestem, is a species of tall grass native to much of the Great Plains and grassland regions of central and eastern North America. It is also known as tall bluestem, bluejoint, and turkeyfoot. Taxon ...

and

switchgrass ''Panicum virgatum'', commonly known as switchgrass, is a perennial warm season bunchgrass native to North America, where it occurs naturally from 55th parallel north, 55°N latitude in Canada southwards into the United States and Mexico. Switch ...

. The two regions are separated by mixed-grass prairie, which contains both short and long grass varieties as well as little bluestem and western wheatgrass. Land used for cattle-grazing is included under this classification, which sustains nearly 50 percent of all United States beef cattle. In Canada, provinces located within the Interior Plains produce nearly 60 percent of all beef cattle. Much of the land in the Interior Plains is used for

agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...

. In the year 2000, 43.8 percent of the Great Plains portion of the Interior Plains were used for agriculture. By far,

wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...

comprises the largest portion of the agricultural yield in region; combined, wheat exports from the Interior Plains make up more than half of the world's exports. Other significant crops produced in the region include

barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ...

corn Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout Poaceae, grass that produces cereal grain. It was domesticated by indigenous peoples of Mexico, indigenous peoples in southern Mexico about 9,000 years ago ...

cotton Cotton (), first recorded in ancient India, is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure ...

sorghum ''Sorghum bicolor'', commonly called sorghum () and also known as great millet, broomcorn, guinea corn, durra, imphee, jowar, or milo, is a species in the Poaceae, grass genus ''Sorghum (genus), Sorghum'' cultivated for its grain. The grain i ...

soybeans The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean. Soy is a staple crop, the world's most grown legume, and an important animal feed. Soy is a key source of f ...

, and

canola file:CanolaBlooms.JPG, Close-up of canola blooms file:Canola Flower.jpg, Canola flower Rapeseed oil is one of the oldest known vegetable oils. There are both Edible oil, edible and industrial forms produced from rapeseed, the seed of several ...

, which is particularly important to Canadian exports. Other sources comprise much smaller portions of the land. In decreasing percentage, forests make up 5.8%, wetland makes up 1.6%, developed land makes up 1.5%, barren land makes up .6%, and land used for mining makes up .1%.

Physiography

The Interior Plains physiographic area stretches across Canada and the United States, and the two governments each use a different hierarchical system to classify their portions. In Canada, the Interior Plains makes up one of seven physiographic areas included in the highest level of classification - defined as a "region" in that country. In the United States it is one of eight physiographic areas (of the contiguous 48 states) included in the highest classification, defined as a "division" there.

Interior Plains in Canada

The Interior Plains of Canada are one of seven physiographic areas included in the highest level classification in that country. That country calls this primary classification level "region." For some of the seven regions, a subregion schema is provided. For other physiographic regions (such as the Interior Plains and Appalachian Uplands) subregions are not developed, but the tertiary level (called "division" in Canada) is used in the mapping data. The following list is of the 14 physiographic divisions in the Interior Plains of Canada. Further information can be found at https://atlas.gc.ca/phys/en/index.html * Alberta Plain * Alberta Plateau * Anderson Plain * Colville Hills * Cypress Hills * Fort Nelson Lowland * Great Bear Plain * Great Slave Plain * Horton Plain * Manitoba Plain * Peace River Lowland * Peel Plain * Peel Plateau * Saskatchewan Plain

Interior Plains in the United States

The following is a breakdown of the secondary (provinces), and tertiary (sections) physiographic areas of the Interior Plains portion in the United States:

Central Lowland

* Dissected Till Plains * Eastern Lake * Osage Plains * Till Plains * Western Lake * Wisconsin Driftless

Great Plains

* Black Hills * Central Texas * Colorado Piedmont * Edwards Plateau * High Plains * Missouri Plateau, Glaciated * Missouri Plateau, Unglaciated * Pecos Valley * Plains Border * Raton

Interior Low Plateau

Highland Rim The Highland Rim is a geographic term for the area in Tennessee, North Alabama, and Kentucky which surrounds the Central Basin. The Central Basin is a geological dome which has subsequently fractured and eroded to produce a basin. The Highland R ...

* Lexington Rim *

Nashville Basin The Nashville Basin, also known as the Central Basin, is a term often used to describe the area surrounding Murfreesboro, Tennessee, in which Nashville is located. The Central Basin was caused by an uplifting which produced a dome known as the ...

References

External links

USGS map showing the subdivisions of the Interior Plains Province within the US

Physiographic Regions
'' Canadian Encyclopedia'' (March 2015) {{Regions of the United States Geography of Alberta Geography of Manitoba Geography of Saskatchewan Geography of the United States Geology of Canada Geology of the United States Physiographic regions of Canada Physiographic regions of the United States Plains of Canada Plains of the United States

Geologic history

Proterozoic Eon (2500 to 539 million years ago)

Paleozoic Era (539 to 252 million years ago)

Mesozoic Era (252 to 66 million years ago)

Cenozoic Era (66 million years ago to Present Day)

Glacial history

Sediment transport

Fluvial processes

Aeolian processes

Current land use

Physiography

Interior Plains in Canada

Interior Plains in the United States

Central Lowland

Great Plains

Interior Low Plateau

See also

References

External links