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Layers of Earth and Continental Drift. Layers of the Earth . 1. Crust- thinnest, outermost layer, 18 miles thick Two Types A. Oceanic- younger, thinner, more dense B. Continental- older, thicker, less dense 2. Mantle- thickest layer, most of Earth’s mass, solid, but can move like playdoh .
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Layers of the Earth • 1. Crust-thinnest, outermost layer, 18 miles thick • Two Types • A. Oceanic-younger, thinner, more dense • B. Continental-older, thicker, less dense • 2. Mantle-thickest layer, most of Earth’s mass, solid, but can move like playdoh. • 3. Outer core-liquid, iron & nickel • 4. Inner core- Center of Earth, solid, iron & nickel
Theory of Continental Drift • Alfred Wegener (1912) • Parts of the Earth’s crust drifts on top of a liquid core. • Named: Pangaea-large supercontinent • Existed 250 million years ago • “Pan”- all “Gea”-Earth • Pangaea broke apart and became the continents we know today. • (see Pangaea animation) http://www.classzone.com/books/earth_science/terc/content/visualizations/es0806/es0806page01.cfm?chapter_no=visualization
Evidence Used to Support Continental Drift • 1. Continents fit together like a jigsaw puzzle. • 2. Same plants and animal fossils that couldn’t fly or swim were found on continents separated today by oceans. • 3. Mountains and glacier scratches on different continents match up. • Wegener’s theory was REJECTED because he couldn’t prove the force that makes the continents move.