Continental Drift

Key Terms Continental Drift Mid-ocean ridge Sea-floor spreading Paleomagnetism

Wegener’s Hypothesis Hypothesized continents once formed part of a single landmass called a supercontinent.

Science Needs Evidence How do each of these strengthen the argument of Continental Drift? Fossil evidence Evidence from Rock Formations Climatic Evidence Mechanisms that cause movement Mid-ocean ridges Sea-floor spreading

Growth of the Atlantic Ocean The Atlantic ocean is spreading at a rate of 1 to 2 cm per year. How many years will it take for the sea floor of the Atlantic Ocean to spread 1 km?

Paleomagnetism Research and Explain each of the following: Please use diagrams with your explainations. Magnetic Reversals Magnetic Symmetry

Prediction If the plates of the world are moving at an average rate of 2 cm per year, how many kilometers will the plates move in 2.5 X 108 years? Produce a map of the Earth and what it will look like 2.5 X 108 years from present. Map should include BOTH present and future locations of the continents and oceans. Use page 5 of your ESRT to determine current directional movement for each plate.

Questions 1. Describe the observation that first led to Wegener’s hypothesis of continental drift. 2. Explain how scientists know that Earth’s magnetic poles have reversed many times during Earth’s history. 3. Identify how magnetic symmetry can be used as evidence of sea-floor spreading. 4. Explain how scientists date sea-floor rocks.

Questions 5. How does evidence that rocks farther from a ridge are older than rocks closer to the ridge support the idea of spreading? 6. Use the following terms to create a concept map: continental drift, paleomagnetism, fossils, climate, sea-floor spreading, geologic evidence, supercontinent, and mid-ocean ridge.