Tic Tac Know Crossword Puzzle

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Across
  1. 6. dense ball of solid iron at the center of the earth
  2. 7. The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary
  3. 8. A deep canyon on the ocean floor
  4. 11. a crack in the lithosphere where rocks move
  5. 13. Alfred Wegener's hypothesis that the continents were once one huge land mass but have since then drifted apart
  6. 15. when two plates slide past each other
  7. 16. the thickest layer of the earth; it consists of two layers- the lithosphere and the asthenosphere
  8. 18. a soft layer on the mantle where the lithosphere floats on
  9. 20. The process by which molten material adds new oceanic crust to the ocean floor
Down
  1. 1. theory that pieces of the Earth's lithosphere are in motion,driven by convection currents in the mantle
  2. 2. where two plates move apart from each other
  3. 3. the layer of rock that forms the Earth’s outer surface
  4. 4. Cause the plates to move; between the lithosphere and the asthenosphere
  5. 5. A deep valley where two plates move apart
  6. 9. A rigid layer made up of the uppermost part of the mantle and the crust
  7. 10. the name of the single landmass that broke apart 225 million years ago
  8. 12. The undersea mountain mountain chain where new ocean floor is produced; a divergent plate boundary
  9. 14. where two plates move toward each other
  10. 17. the german scientist who developed the theory of continental drift
  11. 19. a layer of molten iron and nickel that covers the inner core