Unit 4 Section 1 - Lushman's Science

Unit 4

Section 1

Continental drift and plate tectonics

When the continents were first mapped, what do you think people noticed?

Theory of Continental Drift

Alfred Wegener

~1915, German Meteorologist

Proposed that continents had once been together as a supercontinent "Pangaea"

called

Theory of Continental Drift

The belief was the continents just drifted through the ocean floor making mountains

There was no known mechanisms for the movement

Wegener proposed it was the s rotation and lunar gravitational forces

earth'

Evidence: Theory of continental drift

1. The fit of the continents Continental coastlines appear to fit together like a jigsaw puzzle. For example, South America and Africa.

Evidence: Theory of Continental Drift

2. Fossil Correlation

Fossils of similar organisms found

in matching fossil beds on different

continents.

E.

G. South America and Africa.

E.g. Fossil fern plant (Glossopteris) and an aquatic reptile (Mesosaurus).

Evidence: Theory of Continental Drift

3. Rock Types Type of rock on neighboring continents, shield areas, line up.

E.G. Shield area of South America and of Africa line up.

Evidence: Theory of Continental Drift

4. Structural Similarities

On neighboring continents, structural similarities such as folded mountains line up . E.g. The Appalachian Mountains and Caledonian Mountains.

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