Plate Tectonics Vocabulary

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Across
  1. 3. a plate boundary where two plates move toward each other.
  2. 8. the theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle.
  3. 9. a plate boundary where two plates move away from each other.
  4. 10. the name of the single landmass that broke apart 200 million years ago and gave rise to today's continents.
Down
  1. 1. a deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle.
  2. 2. the process by which molten material adds new oceanic crust to the ocean floor.
  3. 4. the hypothesis that the continents slowly move across earth's surface.
  4. 5. an undersea mountain chain where new ocean floor is produced.
  5. 6. the process by which ocean floor sinks beneath a deep-ocean trench and back into the mantle.
  6. 7. a break or crack in Earth's lithosphere along which the rocks move.