Choices Assignment Crossword

1234567891011121314151617181920
Across
  1. 4. Elevated area of the sea floor.
  2. 5. A chain of volcanic islands generally a few hundred km from a trench.
  3. 8. What is happening typically 5 centimeters per year?
  4. 10. Two plates move towards each other.
  5. 11. mountains formed in. Part by igneous activity associated with the subduction of oceanic lithosphere.
  6. 15. Elongated depression.
  7. 16. less dense.
  8. 18. Hypothesis first proposed by Harry Hess in the 1960s.
  9. 19. Denser portions of oceanic lithosphere descend into mantle at the rate of sea floor production.
  10. 20. Super continent.
Down
  1. 1. a continuous elevated zone on the floor of all major ocean basins.
  2. 2. Linear zones of irregular topography on the deep-ocean floor.
  3. 3. Two plates slide past each other.
  4. 6. A hypothesis which suggested that all present continents once existed as a single super continent.
  5. 7. A narrow, elongated depression of the sea floor.
  6. 9. Two plates moving away from one another.
  7. 12. Cause of a chain of volcanos.
  8. 13. Processes that deform Earth’s crust.
  9. 14. When igneous rocks melt over a temp range.
  10. 17. More dense.