Regional Geography of North America P 160-180 Chapter 6 Regional Geography of North America P 160-180
Introduction North America is made up of a variety of landscapes Earth is 4.5 billion years old Three layers: crust, mantle, and core
Earth’s Layers The crust is a thin layer of rock about 5-35 km thick Broken up into large and small pieces – plates Under the crust is the mantle which is molten rock known as magma The centre of the earth is the core that is hot, and dense, and solid in the centre Heat of the core is responsible for heating the mantle Magma moves, causing the plates of the crust to move or break
Forming of Continents From 600 to 225 million years ago, the continents of North America, Africa, and Europe were joined Tectonics created the Canadian Shield 2 billion years ago
Fold Mountains When two plates are pushed together over millions of years, the rock layers crumple up and form fold mountains e.g. Rocky Mountains and Appalachian Mountains
Volcanic Mountains When the crust breaks while it is folding, molten rock pushes through and creates volcanic mountains E.g. Canadian Shield and Cascade Mountains
Ice Ages Ice Ages eroded geographic features Prolonged period of cooling about 60 million years ago By 2.5 million years ago, glaciation of the northern hemisphere widespread During last ice age (25 000-10 000 years ago), glaciers covered most of North America Glaciers are literally rivers of ice
Glaciers in North America
Effects of Glaciation Melted water drained into earth’s oceans Some of the melted water was blocked by debris the glaciers had scraped away Formed lakes Deposits of silt laid down flat, bare land like the prairies Scraped the rocks bare, leaving very little soil Canadian Shield Left mounds of debris hills
North American Settlers Before European settlement, North America was filled with forests, swamps, and deserts First Nations peoples did not really change the environment much European settlers to North America felt that the environment should be modified to suit their needs
Some final definitions Topography: the shape of the land Climate: the prevailing conditions of temperature and precipitations Vegetation: the plants that grow naturally in an area
8 Geographic Regions of North America Information taken from Heidi Robinson’s powerpoint on SlideShare
Appalachian Region
Topography Travels from Newfoundland through, Maritime provinces through, U.S. as far as Alabama and Georgia Many different mountain ranges About 300,000,000 years old Lots of continual erosion Consists of fertile plateaus and river valleys Coal, oil and gas can be found in sedimentary rock
Climate Heavily affected by ocean currents Grand Banks had lots of fish which was the main attraction for European explorers and settlers
Vegetation Mixed coniferous (evergreen) and deciduous (shed leaves annually) trees
The Coastal Plains
Topography Extends from Cape Cod along Atlantic coast which includes, Florida then going westward and traveling along Gulf Of Mexico continuing to Mexico Average elevation is below 200m above sea level Mostly flat Swamps and marches that give transportation routes and agricultural land
Climate North – cold and snowy winters/hot and humid summers South – subtropical climate, mild to warm winters Hurricanes – late summer to early winter
Vegetation Mainly sandy - some natural vegetation has adapted to this type of soil Lush jungles (in Mexico) Originally pine forests
The Great Lakes – St. Lawrence Lowland
Topography includes triangle created by lakes Huron , Ontario and Erie Smallest of all the geographic regions of North America Several escarpments (Niagara Falls) Has two separate parts Rolling landscape Created by glaciation
Climate Humid continental climate Due to the Great Lakes Winter – cool to cold Summer – warm to hot
Vegetation Very fertile Maple, Beech, Hickory and Black Walnut trees Mixed forests – deciduous and coniferous
The Interior Plains
Topography Bordered on the east by the Canadian Shield and on the west by the Rocky Mountains Bordered to the north by the Arctic Ocean and to the south by the Gulf of Mexico Not entirely flat Gentile rolling hills and deep river valleys 600-1500m above sea level on average Canada’s “Bread Basket of the World”
Climate Continental climate In the heart of the continent Away from the influence of oceans Climate of extremes Long hot summers Cold winters Little precipitation In the north the winters are colder and longer, in the south the summers are warmer Arctic climate in the north with extremely long winters and short summers
Vegetation Grasslands in this prairie area Boreal forest in the northern regions with tundra towards the Arctic
The Canadian Shield
Topography More than 2 billion years old Great volcanic mountains that have been levelled by erosion Geographic foundation of Canada Only in 2 of the US States Barren rock left by glaciation Chaotic pattern of rivers, lakes, swamps and muskeg About 100-500m above sea level on average Most rivers flow towards Hudson or James Bay
Climate As you travel north the winters get longer and colder, and the summers get shorter and cooler
Vegetation Boreal forest covers most of the area North of the tree line, no trees are able to grow due to the very short growing season, little precipitation and permafrost
The Western Cordillera
Topography Along the west coast of North America Range after range of mountains New mountains not yet worn by erosion The Rocky Mountains form the continental divide that determines the flow of most rivers
Climate Maritime climate West coast is moist and mild Winters usually above freezing with cooler summers that the interior of the continent Warm valleys Rain-shadow
Vegetation Varied Forests and deserts Most of the earths forms of vegetation can be found here
The Intermountain Region
Topography Located in U.S. and Canada which falls between the Rocky Mountains, the Cascades and Sierra Nevada Area of high plateaus Isolated mountains Streams and rivers never make it to the ocean (not in all cases) Lots of cattle ranching
Climate Affected by location and elevation Winters can be cool and wet or hot and dry
Vegetation Sparse grasslands to semi-desert or desert plants Pine forests in the higher elevations
The Arctic
Topography Combination of lowlands and mountains Flat near the ocean Mountains in the far north Mostly covered by glaciers
Climate Very severe Very far from the equator Winter lasts for 10 months at a time Summer is very short Actually a desert because of so little precipitation Area is dominated by permafrost
Vegetation Very few life forms Trees cannot grow on the tundra Small shrubs, mosses and lichen can grow