Chapter 8 - Plate Tectonics

Chapter 8 - Plate Tectonics - Chapter 8. Plate Tectonics...

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Chapter 8. Plate Tectonics Theory proposed by Alfred Wegner in 1915 Suggests that: 1. A Supercontinent known as Pangea existed 200 million years ago. 2. The Supercontinent began to break up into smaller continents, which then drifted to their present positions. Evidence: 1. Fossiles match across the seas(Mesosaurus in South America and Africa. 2. Rock types and structures match(Apps. In Eastern North America trend the same way as mountains in the British Isles and Scandonavia). 3. Puzzle pieces- The Continents match up with each other like a puzzle and structures(rocks) are similar in age and type. 4. Climate changes- glacial deposits are found in Southern Africa, South America, India, and Australia today. Plate Tectonic Theory States that the lithosphers is broken into segments called plates which are in motion and change in shape and size. Movement comes from unequal distribution of heat within the Earth(convection cells). Plate Boundaries All major interactions among plates occur at plate boundaries. There are 3 types: 1. Divergent - plates move apart resulting in upwelling of material from the mantle creating new seafloor. 2.
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Chapter 8 - Plate Tectonics - Chapter 8. Plate Tectonics...

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