Theory of Continental Drift and Plate Tectonics Notes PAP

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

Theory of Continental Drift States that the land masses were originally one giant supercontinent that eventually began to break up 200-225 million years ago Explained why earthquakes and volcanic eruptions occur in specific locations Explained how land features were created

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.

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.