1. Chapter 14
Plate Tectonics

2. Lesson 1- The Continental Drift Theory
Pangaea- All continents were joined as one Super continent.
Continental Drift- Theory proposed to explain how Pangaea broke apart so that the continents could attain their current position.
Continents are still drifting.

3. Alfred Wegener In 1910 or 1911- he proposed that Pangaea broke apart
Evidence to support his claim
Continents fit together like puzzle pieces- Coast of South America fits with Coast of Africa
Climate clues
Fossil Clues
Rock Clues

4. Climate Clues
South America, Africa, India, Australia were closer together 280 million years ago.
Climate was cooler and glaciers covered the area
Wegener studies the grooves made by glaciers in the rocks of these different locations.
He noticed the same glacial grooves on each of the continents so he used this as evidence to support his idea

5. Fossil Clues
Some animals and plants are unique to a continent such as kangaroos to Australia.
These continents are also separated by large oceans
Fossils can’t travel by natural means such as wind and these organisms can’t swim long distances.
Therefore he surmised that the continents were once joined.

6. Fossil Clues
Glossopteris- a plant has been discovered in rocks in South America, India, Africa, Australia, and Antarctica
Mesosauras- a reptile have been
found in the same places.

7. Rock Clues
Wegener noticed that mountain ranges on different continents had common origins.
Today, geologists can determine how the rocks formed.
For example, large scale volcanic eruptions occurred on the Western coast of Africa and the Eastern coast of South America
The Caledonian Mountain Range in Europe and the Appalachian Mountain range in North America are similar.

8. So why was Wegener considered crazy?
He held steady to his beliefs until his death in 1930.
He could not explain how they moved. That is why the scientist did not believe him.
It is a slow process- he could not explain how a slow process could move the continets
He also could not explain what forces moved the continents.