Plate Tectonics Webquest

Who was Alfred Wegener? Get more information about him here:

 

Alfred Wegner discovered the theory of continental drift. He could not prove his theory completely therefore not many people believed him.


What was Wegener's theory called?

 

Continental Drift


What is Pangaea?

 

Pangaea is what is believed to be a supercontinent of all the continents put together long ago.


How did Wegener try to prove his theory

 

He saw a jigsaw fit between Africa and South America, he found fossil of the same plants and animals on both continents. There are mountains similar in age and structure on both parts of Europe and Canada. Lastly there were Ice sheets In areas that are very hot, he believed they broke off then started to melt.

 

Why did the scientific community reject his theory?

 

Because he couldn’t explain the mechanism that was strong enough to move entire continents.

 

Which Canadian scientist revived interest in Wegener's theory and helped develop the theory of Plate Tectonics?

 

J. Tuzo Wilson

 

When was Plate Tectonics developed?

 

In 1968

 

 

 

The earth’s crust under the ocean is about 4 miles ( 6.43 km) thick.   Continental crust is about 40 miles ( 64.3 km) thick.  Continental crust is about 10 times more thick than oceanic crust.

 

Continental plates collide on the Asian continent forming the Himalayas Mountains. This is a convergent (coming together) plate boundary.

 

Where continental plates collide, they crunch together and form mountains and cause earthquakes

 

When an oceanic plate sinks into the mantle under a continental plate, it melts and becomes part of the mantle. Large earthquakes often occur in these areas. Mountains are made on the continental plate. Volcanoes also form within the continental plate when melting occurs in the mantle above the sub ducting oceanic plate, feeding "magma chambers" within the crust. The magma can find its way to the surface as volcanoes.

 

The birth of new crust occurs when the oceanic plate is pulled apart in the middle.  The magma rises up and forms layers of new crust This cause a “mid-ocean ridge” or separating to be formed.  There is a “mid-ocean ridge” in the middle of the Atlantic ocean between North America and Europe.

 


 

Crust - the rigid, rocky outer surface of the Earth, composed mostly of basalt and granite. The crust is thinner under the oceans.

 

Inner core - the solid iron-nickel center of the Earth that is very hot and under great pressure.

 

Mantle - a rocky layer located under the crust - it is composed of silicon, oxygen, magnesium, iron, aluminum, and calcium. Convection (heat) currents carry heat from the hot inner mantle to the cooler outer mantle.

 

Outer core - the molten iron-nickel layer that surrounds the inner core.

 

How fast is the Mid-Atlantic Ridge spreading?

 

2.5cm per year


Why is Iceland increasing in size?

 

Because it falls between two plates, therefore the two plates are pulling apart, pulling iceland apart.


Name two other places where land is being separated by plate tectonics.

What is the Ring of Fire?

 

Iceland, and Saudi Arabia.

The ring of fire is where a large number of earthquakes and volcanic eruptions occur

 

 

Beside “select a slide to preview below” choose OºE (view centred on equator).

 

What is the continent on the right side of the globe?

 

Africa

 

What is the continent on the left side of the globe?

 

South America

 

What ocean separates these two continents?

 

Atlantic

 

Name the line running through the ocean.

 

Mid Atlantic Ridge

 

Is this feature created where plates are coming together (convergent) or where plates are separating (divergent)?

 

Divergent

 

Which 4 plates are causing the ridge to form?

 

North American, African, South American, and Eurosian

 

What kind of plate boundary is along the west coast of North America?

 

Subduction

 

Which plates are involved?

 

North American and Pacific

 

Where would you most likely feel an earthquake in Canada?

 

British Columbia

 

Why?

 

Because it's where two plates come together, and it could create earthquakes when they pull apart or together

 

Choose OºE (view centred on 45ºN). Notice the red island-this is Greenland.

There is a small island near Greenland that seems to be right in the middle of the ridge.

 

What is the name of this island?

 

Iceland

 

50 million years. If we continue present-day plate motions the Atlantic will widen, Africa will collide with Europe closing the Mediterranean, Australia will collide with S.E. Asia, and California will slide northward up the coast to Alaska.

 

In 100 million years new subduction zones along the eastern coasts of North America and South America will begin to consume the ocean floor separating North America from Africa.  The Mid Atlantic Ridge will be subducted and the continents will come closer together.

 

A new Pangaea called  will be formed in 250 million years with the Subduction of the ocean floor of the North and South Atlantic beneath eastern North America and South America.  This Super continent will have a small Ocean Basin  trapped at its centre.