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Continental Drift Continental Drift Wegner’s Evidence Wegner’s Evidence 1. Matching fossils in S America & W. Africa 1. Matching fossils in S America & W. Africa 2. Climate: tropical fossils are found in Greenland (cold) 2. Climate: tropical fossils are found in Greenland (cold) 3. Matching Rock Layers/Mountains in U.S. and Africa 3. Matching Rock Layers/Mountains in U.S. and Africa Harry Hess - Sea Floor Spreading Evidence Harry Hess - Sea Floor Spreading Evidence 1. Ridges form along cracks in the crust. Crust created here 1. Ridges form along cracks in the crust. Crust created here 2. Drilling Samples of sea floor show youngest rock is near the ridge, oldest is furthest from ridge. 3. Ocean trenches are found far from the ridge. Crust is destroyed here. 2. Drilling Samples of sea floor show youngest rock is near the ridge, oldest is furthest from ridge. Magnetic Reversals Magnetic Reversals The stripes of rock along the ocean floor record these changes and are symmetrical to the mid ocean ridge. The stripes of rock along the ocean floor record these changes and are symmetrical to the mid ocean ridge. 3. Ocean trenches are found far from the ridge. Crust is destroyed here. Why isn’t the circumference of the Earth getting Bigger? Why isn’t the circumference of the Earth getting Bigger?
