Continental Drift Unit Essential Question: How does the Earth recycle and renew its surface? Presentation Objectives: Define the theory of continental drift. Explain the different evidence that supports the theory of continental drift. What A Dynamic Place! • Even though the Earth seems relatively unchanging, scientists have evidence that the Earth’s surface actually is changing. • The continents are moving! • The Theory of Continental Drift is the theory which proposes that the Earth’s continents had once been joined as one single landmass. • Known as Pangaea • Pangaea broke apart about 200 million years ago. • The continents drifted to their present positions. • They Fit Together! • Early mapmakers noticed that the continents looked like they fit together like puzzle pieces. Observation 1 • Not a perfect fit! • The continents as we see them do not fit well. • You get a perfect fit when you consider the continental margins. • Continental margins are the edges of the continents that are underwater. Observation 2 • Rock Formations • Different continents showed the same rock types in exactly the same order. • These rocks and minerals were not found on the ocean floor between the continents. Diamonds found indicate areas of high pressure!