Chapter 6Regional Geography of North AmericaP 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