Friday, September 12, 2014

North America Continent Brief Geographical Overview

It lies wholly within the Northern Hemisphere.

It greatest extent, north to south 7400km and east to west 5700km.

It was discovered by Columbus in 1492.

It is bounded by the Arctic, Atlantic and the Pacific Oceans in the north, east and west respectively, while in south, it connected with South America through the Isthmus of Panama. 
Culturally, it is divided into the Anglo America (Canada and U.S.A.) and Latin America (South of U.S.A.) including Mexico and Central American Countries.

The North American Continent can be divided into a number of major structural areas.

1. The Western Cordillera

2. The Canadian Shield

3. The Great Plains 

4. Central Lowlands

5. The Appalachians

6. Gulf Atlantic Coastal Plain.

The Western Cordillera - About 80 million years ago the Pacific and North American Plates collided, uplifting the western cordillera. This consists of the Aleutian, Coast, Cascade and Sierra Nevada Mountains and the inland Rocky Mountains. These runs parallel from the Arctic to Mexico. 

The Canadian Shield - Spanning northern Canada and Greenland, this geographically stable plain form the heart of continent, containing rocks over two billion year old. A long history of weathering and repeated glaciations has scoured the region, leaving flat plains, gentle hummocks, numerous small basin, the lakes and the bay and the islands of the Arctic. It is rich source of various metallic minerals. So it is also known as “Treasure House of Canada.”

The Great Plains and Central Lowlands - Deposits left by retreating glaciers and rivers have made this vast flat area very fertile. In the north this result of glaciations with deposits upto 1-7km. thick, covering the basement rocks. To the south and west, the massive Missouri/Mississippi River system has for centuries deposits silt across the plains, creating broad, flat flood plains and deltas.

The Appalachians - The Appalachian Mountains, uplifted about 400 million years ago, are some of the oldest in the world. They have been lowered and rounded by erosion and now slope gently towards the Atlantic across a broad coastal plain. It is a great source of coal.

‘Tornado alley” in the Mississippi Valley suffers frequent tornadoes. 

Much of the southwest is semi desert, receiving less than 12 inches of rainfall a year.

The ‘Grand Canyon’ in the Colorado Plateau was created by the downwards erosion of the Colorado River.

Much of North America is almost empty, especially frozen for north. Population density are highest in the highlands of Mexico and central America, the Coastal plain stretching from the Gulf of Mexico along the Atlantic coast, the Great Lakes area, and the Pacific coast.

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