1. Theory of Continental Drift
and
Plate Tectonics Notes
PAP

2. Alfred Wegener
Meteorologist who contended the land masses of Earth were once one giant supercontinent
Went on multiple expeditions to prove his theory
Developed the Theory of Continental Drift
Pangaea – the name of the giant supercontinent

3. Theory of Continental Drift
States that the land masses were originally one giant supercontinent that eventually began to break up million years ago
Explained why earthquakes and volcanic eruptions occur in specific locations
Explained how land features were created

4. Wegener’s Evidence
The continents appeared to fit together like puzzle pieces.
Geologic structures on different continents had the same structure and sediment patterns
Fossil evidence – fossils of the same species were found on continents that were oceans apart
Evidence of dramatic climate changes on some continents
Weakness: Wegener couldn’t explain how the continents were moving.

5. Seafloor Spreading
Results in new crust being formed while old crust is recycled
Occurs at a mid-ocean ridge
Magma oozes up from the center of the ridge.
Then it cools and hardens.
As more magma oozes up, it pushes the oldder rock out and away from the center of the ridge.
This causes the seafloor to spread out.