Geography of North America

Source: Wikipedia, the free encyclopedia.

Global view centered on North America

North America is the third largest continent, and is also a portion of the third largest supercontinent if North and South America are combined into the Americas and Africa, Europe, and Asia are considered to be part of one supercontinent called Afro-Eurasia. With an estimated population of 580 million and an area of 24,709,000 km2 (9,540,000 mi2), the northernmost of the two continents of the Western Hemisphere[1] is bounded by the Pacific Ocean on the west; the Atlantic Ocean on the east; the Caribbean Sea on the south; and the Arctic Ocean on the north.

The northern half of North America is sparsely populated and covered mostly by Canada, except for the northeastern portion, which is occupied by Greenland, and the northwestern portion, which is occupied by Alaska, the largest state of the United States. The central and southern portions of the continent are occupied by the contiguous United States, Mexico, and numerous smaller states in Central America and in the Caribbean.

The continent is delimited on the southeast by most geographers at the Darién watershed along the Colombia-Panama border, placing all of Panama within North America.[2][3][4] Alternatively, a less common view would end North America at the man-made Panama Canal. Islands generally associated with North America include Greenland, the world's largest island, and archipelagos and islands in the Caribbean. The terminology of the Americas is complex, but "Anglo-America" can describe Canada and the U.S., while "Latin America" comprises Mexico and the countries of Central America and the Caribbean, as well as the entire continent of South America.

Natural features of North America include the northern portion of the

St. Lawrence draining into the Atlantic. The Colorado, Colombia, and Yukon Rivers drain west to the Pacific Ocean
.

Nuevo Leon and Tamaulipas
.

The Blue Marble, NASA; east more rain than west.

Paleogeography

The paleogeological origins of the basement rocks underlying North America.
Age of the bedrock underlying North America, from red (oldest) to blue, green, yellow (newest).

Seventy percent of North America is underlain by the

Pangea, and Laurasia
supercontinents.

Roughly 3 million years ago (

human migration from Asia to the Americas between 40,000 and 15,000 years ago.[11]

North America can also be divided into four great regions:[citation needed]

  • Canadian Arctic
    ;
  • the geologically young, mountainous west: including the Rocky Mountains, the Great Basin, California and Alaska;
  • the raised but relatively flat plateau of the Canadian Shield in the northeast;
  • the varied eastern region: including the Appalachian Mountains, the coastal plain of the
    Atlantic Seaboard, and the Florida peninsula.[12]

Mexico and its long plateaus and cordilleras fall largely in the western region, although the eastern coastal plain does extend south along the Gulf.

  North American Plate (center top)
  Caribbean Plate (center)

Physiography

North America may be divided into at least five major

physiographic regions:[citation needed
]

Canadian Shield
This is a geologically stable area of rock dating between 2.5 and 4
Gya that occupies most of the northeastern quadrant, including Greenland
.
Appalachian Mountains
The Appalachians are an old and eroded system that formed about 1.3
Gya[13] and extends from the Island of Newfoundland to Alabama
.
Atlantic Coastal Plain
The plain is a belt of lowlands widening to the south that extends from south New England to Mexico.
Interior Lowlands
The lowlands extend down the middle of the continent from the
Mackenzie Valley to the Atlantic Coastal Plain, and include the Great Plains on the west and the agriculturally productive Interior Plains
on the east.
North American Cordillera
The cordillera is a complex belt of mountains and associated plateaus and basins some of which were formed as recently as 100–65 Ma, during the Cretaceous. The cordillera extend from Alaska into Mexico and includes two orogenic belts — the Pacific Margin on the west and the Rocky Mountains on the east — separated by a system of intermontane plateaus and basins.[10]

The Coastal Plain and the main belts of the North American Cordillera continue in the south in Mexico (where the Mexican Plateau, bordered by the Sierra Madre Oriental and the Sierra Madre Occidental, is considered a continuation of the intermontane system) to connect the Transverse Volcanic Range, a zone of high and active volcanic peaks south of Mexico City.

The vast majority of North America is located on the North American Plate, centered on the Laurentia craton. Parts of California and western Mexico form the partial edge of the Pacific Plate; the two plates meet along the San Andreas Fault. The southern portion of the Caribbean and parts of Central America compose the much smaller Caribbean Plate.

The western mountains have split in the middle, into the main range of the Rockies and the Coast Ranges in California,

Mount McKinley/Denali
in Alaska.

Three countries (Canada, the United States, and Mexico) make up most of North America's land mass; they share the continent with 34 other island countries in the Caribbean and south of Mexico.

Geographic center of North America

The geographic center of North America is near Center, North Dakota,[14] according to Peter Rogerson, geography professor at the University at Buffalo, who published a new method of calculating geographical centers.[15]

Earlier placements in 1931 involved geographers balancing a cardboard cutout of a region on a needlelike point to find its center to establish a spot "6 miles west of Balta, Pierce County, North Dakota",[14] at 48⁰ 10′north, 100⁰ 10′west.[16] In 1932, a field stone cairn recognizing this was erected in nearby Rugby, North Dakota at the intersections of U.S. Route 2 and ND State Highway 3.[17][18][19]

Surface and climate

Landforms and land cover of North America
The Great Plains

The

savannas of the Mississippi are analogous to, respectively, the Patagonian Steppes and the pampas of the Piranha, Paraguay, and Rio de la Plata. Thus the Appalachians and the mountain chains of Brazil are regarded as creating similar interruptions to the plains community.[20]

North America extends to within 10° of latitude of both the equator and the North Pole. It embraces every climatic zone, from tropical rain forest and savanna on the lowlands of Central America to areas of permanent ice cap in central Greenland.[20] Subarctic and tundra climates prevail in north Canada and north Alaska, and desert and semiarid conditions are found in interior regions cut off by high mountains from rain-bearing westerly winds.[12] However, most of the continent has temperate climates very favorable to settlement and agriculture. Prairies, or vast grasslands cover a huge amount in mountain ranges.[12]

North America's greatest snowfalls

Greatest Snowfalls
Places Date Inches Centimeters
24 hours Silver Lake, Colorado April 14–15, 1921 76 195.6
1 month Tamarack, California January 1911 390 991
One storm Mt. Shasta Ski Bowl, Calif. February 13–19, 1959 189 480
One season Mount Baker, WA 1998–1999 1, 140 2, 895.6

[21]

Hydrography and deserts

See also: hydrography, evapotranspiration, surface runoff, and percolation

The average

petaliters of water.[22]

River systems

North American Watersheds (Atlantic, Arctic, Great Basin, & Pacific)
Saint Lawrence River on the New York–Ontario border
The Upper Rio Grande by Creede, Colorado
The Columbia River from Canada to the Pacific

Listed below by watershed are some of the more notable rivers in North America. Rivers flow entirely within the United States, unless otherwise noted.[23]

North America map of Köppen climate classification.

Climate and vegetation

There are various plant life distributions in North America. Plant life in the Arctic includes grasses, mosses, and Arctic willows. Coniferous trees, including

sugar pines. Sugar pines are generally confined to the northwestern area of the United States
. The central region of the country has
indigo plant, and beans
.

Deserts

The Sierra Nevada and Cascade mountain ranges run along the entire

air has lost much of its moisture and becomes hot and dry when it reaches the areas east of the coastal mountain ranges.[12] These arid conditions are, in some instances, exacerbated in regions of extremely low altitude (some near or below sea level) by higher air pressure, resulting in drier conditions and adiabatic
heating effects, some of these pocket deserts exist in valleys well north of the Canada–US border in interior British Columbia. What precipitation does fall generally does not last long, lost primarily to evaporation, as well as rapid runoff and efficient water uptake and storage by native vegetation.

Major habitat types of the United States and Canada Ecoregions map of Canada, United States and Mexico

Zoology

North America is home to many native mammal species. Several species of

humming bird, rattlesnake, alligator
, and Cayman of the banks of the streams, and swarms of mosquitoes on the wide plains.

Mining and petroleum

Natural gas drilling rig in Wyoming

The mining and petroleum industries are important in Canada, the United States and Mexico. These natural resources make the region one of the richest on the earth.[1][24]

Rocky Mountains

The Rocky Mountain region is known for vast resources and rich mineral deposits including copper, lead, gold, silver, tungsten or Wolfram, uranium, zinc and Coal, petroleum and natural gas are mineral fuels found.[1][24] Old mine tailings are present in the Rocky Mountain landscape.

Agriculture and forestry

Agriculture and forestry are two major industries. Agriculture includes arid land and irrigated farming and livestock grazing.[1] Livestock are often moved between high-elevation summer pastures and low-elevation and winter pastures.

See also

Notes

  1. ^ a b c d "Geographic Guide - Images of North America". Retrieved October 11, 2006.
  2. ^ "Americas" Standard Country and Area Codes Classifications (M49), United Nations Statistics Division
  3. ^ "North America" Archived October 21, 2006, at the Wayback Machine Atlas of Canada
  4. ^ North America Atlas National Geographic
  5. ^ "United Plates of America". Smithsonian Museum of Natural History. Retrieved on 2009-01-31.
  6. ^ Thompson, Andrea (2008-09-25). "Oldest rocks on Earth found". NBC News. Retrieved 2009-02-01.
  7. doi:10.1126/science.1161925
    .
  8. ^ Brahic, Catherine (2008-09-26). "Discovery of world's oldest rocks challenged". New Scientist. Retrieved 2009-02-01.
  9. ^ "Rodinia" Archived 2009-02-18 at the Wayback Machine (2005). Palæos. Retrieved on 2009-02-01.
  10. ^ a b Jones, Steve. "North America's Geology and Geography". USA Today. Retrieved August 19, 2006.
  11. ^ "Historical & Cultural Significance" (1995). Bering Land Bridge Natural Preserve.
  12. ^ a b c d "Encyclozine - North America". Retrieved October 11, 2006.
  13. ^ Thomas, William A.; Hatcher, Jr., Robert D. (2021). "Southern-Central Appalachians-Ouachitas Orogen". Encyclopedia of Geology. 4 – via Elsevier Science Direct. The foundations of the Appalachian-Ouachita orogen were laid when the assembly of supercontinent Rodinia was completed. The collisional events were accompanied by high-grade metamorphism and magmatism during the Grenville orogeny in the time span of 1300–950 Ma.
  14. ^ a b Yin, Steph (January 25, 2017). "North America's Geographical Center May Be in a North Dakota Town Called Center". The New York Times. Retrieved December 30, 2018.
  15. doi:10.1080/00330124.2015.1062707
    .
  16. ^ "Elevations and Distances in the United States". 1995. Archived from the original (Online Edition) on July 22, 2012. Retrieved February 5, 2009. No marked or monumented point has been established by any government agency as the geographic center of the 50 States, the conterminous United States, or the North American continent.
  17. ^ Daley, Jason (January 30, 2017). "New Calculations Reposition the Geographical Center of North America". Smithsonian. Retrieved August 9, 2021.
  18. ^ Bhagat, David (May 30, 2021). "The debate over the Geographical Center of North America". CBS News. Retrieved August 9, 2021.
  19. ^ "About Us". Rugby Chamber of Commerce. Retrieved August 9, 2021.
  20. ^ a b "North America climate". Retrieved August 19, 2006.
  21. ^ "Private Tutor". Infoplease.com. April 11, 2004. Retrieved June 30, 2010.
  22. ^ North America water resources.
  23. USGS
    GNIS database.
  24. ^ a b "Fact Monster - North America: Resources and Economy". Retrieved October 11, 2006.

References

  • "Deserts of America". The Golden Treasury of Knowledge. book 13. Vol. 4. Fratelli Fabbri. 1961. pp. 1008–1091. 61-10594.
  • "Geography of North America". Universal World Reference Encyclopedia. book 1. Vol. 11. V.S. Thatcher. 1964. pp. 231–233. 64-12955.

Bibliography

Map and aerial photos

External links

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