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Plate Movements

Plate Movements. The Basics. Continental Drift Theory. Alfred Wegener (1910s) stated that some 250m yrs ago a single giant continent called “Pangaea” had slowly broken up and drifted apart to give rise to the present continents of the world. Evidences? Main weakness?.

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Plate Movements

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  1. Plate Movements The Basics

  2. Continental Drift Theory • Alfred Wegener (1910s) • stated that some 250m yrs ago a single giant continent called “Pangaea” had slowly broken up and drifted apart to give rise to the present continents of the world. • Evidences? • Main weakness?

  3. Continents were once a supercontinent called Pangeae • Broke up into 2 called Laurasia and Gondwanaland • It slowly broke up further to form the continents today. • Continents fit together like a jigsaw puzzle • Fossils of flora and fauna of similar species are found in different continents • Evidence of rocks that went through glaciation are found at the southern tips of Africa and south America.

  4. Evidence 1

  5. Evidence 2

  6. Plate tectonic Theory • 1950s, describes the Earth as a restless planet • theory suggests Earth’s crust is made up of 7 major crustal plates Continental plates: Oceanic plates: • N. American plate - Pacific plate • S. American plate - Nazca plate (minor) • African plate • Eurasian plate • Indo-Australian plate • Antarctic plate

  7. Why do plates move? • Because of convection currents moving from the hot inner parts of the Earth • drag the plates above them • Heat causes magma in mantle to expand and rise • Magma which has risen spreads out beneath the plates and move away from each other. • Magma cools and drags the plates towards each other. • Repeated heating n cooling causes the currents.

  8. The restless earth • Video on the restless earth

  9. What are the possible landforms from plate movements?

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