Comprehensive Geography and Physical Features of North America
Historical Context and Nomenclature
Earliest Inhabitants: The original inhabitants of North America are believed to have migrated from Asia almost ago.
Christopher Columbus: Reached North America in . Mistaking the continent for Asia, he referred to the indigenous population as "Red Indians"—a term known today as Native Americans or Amerindians.
Amerigo Vespucci: The Americas were named after this Italian explorer, who was likely the first European to explore South America and document detailed written accounts of the continent.
Political Geography: Countries and Capitals
Antigua and Barbuda: St. John's
Bahamas: Nassau
Barbados: Bridgetown
Belize: Belmopan
Canada: Ottawa
Costa Rica: San Jose
Cuba: Havana
Dominica: Roseau
Dominican Republic: Santo Domingo
El Salvador: San Salvador
Grenada: St. George's
Guatemala: Guatemala City
Haiti: Port-au-Prince
Honduras: Tegucigalpa
Jamaica: Kingston
Mexico: Mexico City
Nicaragua: Managua
Panama: Panama City
Saint Kitts and Nevis: Basseterre
Saint Lucia: Castries
Saint Vincent and the Grenadines: Kingstown
Trinidad and Tobago: Port of Spain
United States: Washington, D.C.
Major Physical Regions of North America
North America is divided into four primary physical regions:
The Western Cordillera
The Central Lowlands
The Eastern Highlands
The Canadian Shield
The Western Cordillera
Definition and General Characteristics:
The Western Cordillera consists of a series of young fold mountains running parallel to each other along the entire western coast of North America.
The word cordilleras originates from Spanish, where it signifies 'ropes' or 'cords', describing ranges that resemble twisted ropes.
Acts as a major physical barrier to moisture-laden winds from the Pacific Ocean, causing relief rainfall and creating regional rain shadow zones.
Tectonic and Geothermal Activity:
Forming part of the Pacific Ring of Fire, the region experiences frequent earthquakes and possesses active volcanoes.
Volcanic Eruptions: Alaska's Redoubt Volcano erupted in .
Yellowstone National Park: Renowned for geothermal features including hot springs, mud pools, and geysers.
Mechanics of Geyser Formation:
A geyser is a hot spring from which water and steam erupt intermittently.
Formation requires three conditions:
An abundant supply of water.
Very hot subsurface rocks.
A rock chamber with a small, restricted opening.
Process: Rain seeps through porous rocks into a rock chamber with a small opening. Magma beneath the surface heats the water into superheated steam. Pressure builds up within the chamber until the steam shoots out violently.
Steamboat Geyser: Situated in Yellowstone National Park, it is the tallest geyser in the world; it erupted in and last erupted in .
Sub-Chains of the Western Cordillera (East to West):
The Eastern Chain (Rocky Mountains):
The broadest chain within the Cordillera, characterized by high peaks, glaciers, and snowfields.
The Rocky Mountains stretch for over from British Columbia in Canada to the southwestern tip of the United States.
The highest peak in the Rockies is Mt Elbert at .
Forms the Continental Divide, acting as the primary watershed separating rivers that drain west into the Pacific Ocean from those flowing east and north into the Atlantic and Arctic Oceans.
* **The Central Chain**:
* Forms the middle portion of the Western Cordillera.
* Includes the Cascade Range in the north and the Sierra Nevada in California.
* **The Pacific Coast Range**:
* Runs directly along the Pacific coast from Alaska to California.
* Comprises the Alaskan Range, Coast Mountains, California Coast Ranges, Peninsular Ranges, and Sierra Madre in Mexico.
* The Central Valley of California is situated between the California Coast Ranges and the Sierra Nevada.
* Denali in the Alaska Range is the highest peak in North America, reaching an elevation of .
Intermontane Plateaus and Basin Topography:
Extensive intermontane plateaus lie between the parallel ranges of the Western Cordillera: the Columbia Plateau, the Colorado Plateau, and the Mexican Plateau.
These plateaus receive minimal precipitation because lofty western mountain ranges block rain-bearing Pacific winds.
Rivers traversing these arid plateaus are fed by melting snow from the Rockies and carve deep canyons.
The Grand Canyon: Formed by the Colorado River flowing through the Colorado Plateau, measuring deep, wide, and long. Rocks and water appear to change color by the hour and season.
The Columbia Plateau: Drained primarily by the Snake River.
The Great Basin: Located east of the Sierra Nevada and south of the Snake River; a vast, arid area of inland drainage featuring the Great Salt Lake at its center.
Known for its Basin and Range topography, which consists of parallel mountain ranges interspersed with lowlands.
Relief Rainfall Mechanism:
Warm, moisture-laden air moving off the Pacific Ocean is forced to rise when encountering mountain ranges.
As the air rises, it cools, causing water vapor to condense and fall as relief or orographic rain.
Most rainfall occurs on the windward side of the mountain.
As air crosses the crest and descends the leeward slope, it warms up, bringing little to no rain and creating a rain shadow area on the leeward slope.
The Central Lowlands
Extent and Geographic Boundaries:
Stretch from the Arctic shores and Hudson Bay in the north down to the Gulf of Mexico in the south.
Hemmed in by the Western Cordillera to the west and the Eastern Highlands to the east.
Subregions and Drainage:
Eastern Region: Low-altitude plains drained by the Mississippi River and its tributary, the Ohio River.
Western Region (High Plains): Higher-altitude plains drained by the Missouri River, Platte River, and other tributaries of the Mississippi River.
The plains are made fertile by thick layers of sediment brought down by glaciers and river systems.
Agricultural History and the Dust Bowl:
Following First World War, widespread wheat cultivation was established across the plains.
A severe series of droughts caused farmers to abandon cultivation, leaving topsoil unprotected by vegetation.
Strong winds blew away the dry topsoil, transforming a large region covering the states of Nebraska and eastern Colorado into a human-made desert known as the Dust Bowl.
Conditions have improved through government-enforced soil conservation practices, including tree planting, grass cover anchoring, and contour ploughing.
The Eastern Highlands (The Appalachians)
Physical Features and Elevation:
The Appalachian or Eastern Highlands are old fold mountains extending for almost from Newfoundland and Labrador in Canada to central Alabama in the United States.
Once higher than the Rockies, their elevations have been significantly reduced over time by glacial erosion.
The highest peak is Mt Mitchell at .
Piedmont Plateau and Watershed Development:
A piedmont plateau is located at the eastern foothills of the Appalachian Range.
The eastern edge of the plateau slopes sharply toward the Atlantic coast, creating springs, streams, waterfalls, and rivers.
Tennessee Valley Authority (TVA): Established in to utilize regional water sources for navigation, power production, land reclamation, and watershed development.
Urban and Mineral Resources:
Major Atlantic cities located in this zone include New York, Philadelphia, Baltimore, and Washington, D.C.
The Appalachians and Piedmont region contain rich deposits of coal, copper, zinc, and lead.
The Canadian Shield
Geological Structure and Glaciation:
A vast plateau composed of hard, old volcanic rocks, structural geology similar to the Deccan Plateau.
During past Ice Ages, the region was covered by thick continental ice sheets.
Moving ice sheets scraped and eroded the land surface into a peneplain, while heavy boulders dragged by moving glaciers carved out deep hollows in the bedrock.
Lakes and Economic Importance:
When the Ice Ages ended, water filled these scraped hollows to form thousands of lakes.
Today, the shield functions as a peneplain containing lakes large enough to be considered inland seas.
The Great Lakes: Superior, Michigan, Huron, Erie, and Ontario.
Other Major Lakes: Lake Winnipeg, Great Bear Lake, and Lake Athabasca.
Niagara Falls: Located between Lake Erie and Lake Ontario.
The Canadian Shield contains extensive deposits of mineral resources.
Coastal Features, Peninsulas, Gulfs, and River Systems
Coastline and Major Peninsulas:
North America features a mostly smooth coastline.
Prominent peninsulas jutting out include the Labrador Peninsula, Nova Scotia Peninsula, Florida Peninsula, Baja California Peninsula, and Yucatan Peninsula.
Gulfs and Bays:
Major sea inlets include the Gulf of Mexico, Hudson Bay, Gulf of Alaska, Amundsen Gulf, and Ungava Bay.
The Gulf of Saint Lawrence forms the mouth of the Saint Lawrence River.
The Gulf of California is bordered by the Baja California Peninsula on the west and mainland Mexico on the east.
River Systems by Drainage Group:
Gulf of Mexico Drainage Group:
The Mississippi River, Missouri River, and their tributaries drain the lower Central Lowlands, originating in the Western Cordillera.
The Ohio River and Tennessee River originate in the Appalachians and join the Mississippi River system.
The Mississippi River is the largest river in North America and serves as a primary trade and shipping route.
The Rio Grande River forms the international border between Mexico and the United States.
Atlantic Ocean Drainage Group:
The Saint Lawrence River is the primary drainage river in this group.
Numerous smaller rivers flow from the eastern slopes of the Appalachian Mountains directly into the Atlantic Ocean.
