Forces Building the LandForces Building the Land

Chapter 2Chapter 2

Key WordsKey WordsDefine the following terms in your own words and then with the definition from the back of your text.

• Plates• Plate tectonics• Region • Seismologist• Convection currents• Subduction zones• Geologic time

• All the earth’s surface is made up of different landforms-mountains, valleys, hills, plains, and lowlands

• How did all these landforms get there?

• What caused the earth to be this way?

• How was the earth shaped and built?

What we are going to look at in this chapter…

The Geologic age of the Earth

The ability of parts of the Earth’s crust to move around

How volcanoes and earthquakes are formed by plate tectonics

Moving Continents: The Theory of Plate Moving Continents: The Theory of Plate TectonicsTectonics

•Six major plates cover the Earth’s surface. These plates are like large slabs of rock that make up the Earth’s crust (Outer layer of the earth)

•These plates have been moving around under the Earth’s surface for billions of years because of forces called PLATE TECTONICS.

• The movement of the plates is caused by convection currents coming from the earth’s core.

• These currents can cause plates to move apart or come together.

Convection currents

Show slide show of plate tectonics (2) Show slide show of plate tectonics (2) Teachers domain Plate Tectonics: Alfred WegenerTeachers domain Plate Tectonics: Alfred Wegener

Movement of plates

Global Hotspots p. 15Global Hotspots p. 15

• When plates move apart from one another, magma rises through the open space and then cools, forming a ridge.

Converging PlatesConverging Plates

• If plates come together, two things can happen: If they crash into each other, they form a mountain chain.

• If one plate slides below another, a volcano is created.

The Sudbury Basin The Sudbury Basin

The Big Nickel, Sudbury ONThe Big Nickel, Sudbury ON

Most Volcanic activityMost Volcanic activity

Geologic ErasGeologic Eras

Take a trip into the Earth’s Take a trip into the Earth’s HistoryHistory

http://www.scotese.com/http://www.scotese.com/

Geologic TimeGeologic TimePrecambrian Era• The Earth formed from a mass of floating gas• The era lasted 4 000 000 000 years• During this period, many cycles of mountain

building and erosion took place• As millions of years passed, land and

ocean developed• First living organisms were single celled and a

few multi-celled developed at the end of the era

• 87% of the Earth’s history was during this time

Precambrian EraPrecambrian Era

Paleozoic EraPaleozoic Era

• Canadian Shield gradually worn away by forces of erosion

• Eroded rock particles were called sediments• Sediments were moved by rivers and deposited

in the shallow seas which surrounded the shield• Sediments were compressed (pushed

together) into sedimentary rock• These rocks formed bedrock• Sedimentary rock was pushed to form the

Appalachian mountains• First animals were fish, shell fish and

amphibians—fossils were formed

Mesozoic EraMesozoic Era

• The Rockies started to form at the end of the era. These are also fold mountains formed by the folding of rock.

• Climate was warm, there were swamps and forests

• Dinosaurs and reptiles were present• Vegetation that fell to the ground got covered

with water and sand• Over millions of years, the pressure of the

sediments compressed into layers of vegetation and then turned into coal deposits, now found in Alberta and Saskatchewan.

Animals in the Mesozoic EraAnimals in the Mesozoic Era

Cenozoic EraCenozoic Era

• Final changes that gave Canada its shape• More mountain folding and faulting• The sea disappeared and the land rose—the

Prairies were formed• Glaciers-First activity 1 million years ago• They acted like giant bulldozers that scraped

and gouged the land• When they melted large amounts of clay, sand

and silt were dumped into the Canadian Shield• Glaciers created the great lakes and other rivers• Glaciation happened 4 times during this era• Mammals now existed

Reptile Family TreeReptile Family Tree

Cenozoic EraCenozoic Era

• Final changes that gave Canada its shape• More mountain folding and faulting• The sea disappeared and the land rose—the

Prairies were formed• Glaciers-First activity 1 million years ago• They acted like giant bulldozers that scraped

and gouged the land• When they melted large amounts of clay, sand

and silt were dumped into the Canadian Shield• Glaciers created the great lakes and other rivers• Glaciation happened 4 times during this era• Mammals now existed

The Four Eras of Geologic Time

What do you notice?

First Invertebrates

First land plants

First fish

First reptiles

First amphibians

First dinosaurs, mammals, birds

End of dinosaurs

Millions of years ago

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HomeworkHomework

Workbook: pps. 8 -11

On page 8 start at number 3 and continue.

TEXT: pg. 19 #s 1-2

Label the Landform regions and create a legend wb. P. 12