Geography of Western Canada

Physical Regions of Western Canada

Geological features

• The physical geography of Western Canada has made development a challenge

• Each region has distinct landforms, climatic conditions, and geological features

• Three physical regions of Western Canada: the Canadian Shield, the Interior Plains, and the Western Mountains

The Canadian Shield

The Canadian Shield

• The Canadian Shield was once a volcanic mountain range as high as the Himalayas

• Millions of years of weathering and erosion have wore it down into a landscape of exposed rocks and lakes

• Originally made of igneous rock

• Igneous rock: formed by the solidification of molten material

• Over time, changed by heat and/or pressure into metamorphic rock

• The Canadian Shield is rich in minerals such as copper, gold, lead, and nickel

• The exposed rock makes the land unsuitable for agriculture and settlement

The Interior Plains

The Interior Plains

• The area between the Rocky Mountains and the Canadian Shield

• Formed as eroded material from the Canadian Shield was deposited in layers

• Layers of sedimentary rock

The Interior Plains

• Millions of years ago, the Interior Plains had a tropical climate

• Covered by water, plants, and animals

• Over time, these deposits were compressed in layers of sedimentary rock to form rich deposits of fossil fuels and evaporites

The Western Mountains

• The Western Mountains are a cordillera

• Parallel mountain ranges, separated by a series of plateaus and valleys

• Formed by tectonic plate collisions, causing the Earth’s crust to buckle

The Western Mountains

• Tectonics caused the terrain to form valleys, plateaus, and trenches

• Erosion from rivers and glaciers formed the jagged, rugged, and mountainous landscape we know today

• Alluvium (sediments carried by off rivers) formed fertile river valleys, such as the Fraser River Valley

• Rich in minerals, copper, gold, molybdenum, and coal

Ancient State

Canadian Shield Interior Plains Western Mountains

• Volcanic mountains

• As high as the Himalayas

• Igneous rock

• Tropical climate

• Covered by water

• Series of plates moving toward one another

Significant Changes

Canadian Shield Interior Plains Western Mountains

• Millions of years of weathering and erosion

• Heat and pressure

• Eroded material laid down at edges

• Occasional flooding

• Deposits compressed

• Plate collision

• Pressure of plate tectonics

• Erosion from rivers and glaciers

Result of Changes

Canadian Shield Interior Plains Western Mountains

• Worn down into an exposed landscape of rocks and lakes

• Changed to metamorphic rock

• Flood deposits of plants and animals

• Deposits of fossil fuels and evaporites

• Earth’s crust buckled, lifted into the air

• Valleys, plateaus, and trenches formed

• Fertile valleys

Appearance Today

Canadian Shield Interior Plains Western Mountains

• Hard, rigid, exposed rocks

• Horizontal layers of sedimentary rock

• Flat and rolling grasslands

• Cordillera: series of parallel mountain ranges separated by a series of plateaus and valleys