P6 Crossword Puzzle

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Across
  1. 3. The Mariana ________ in the Pacific Ocean is the deepest landform on Earth.
  2. 5. Scientists were able to determine the age of the ocean floor and create ________ maps.
  3. 8. By the late 1960s, the concepts of continental drift and seafloor spreading led to a more complete ________ called plate tectonics.
  4. 10. Molten rock below Earth's surface is called ________.
  5. 12. The mid-Atlantic ________ is the youngest part of the ocean.
  6. 14. As the ________ continues to spread apart, the older oceanic crust moves away from the mid-ocean ridge and sinks at ocean trenches.
  7. 15. Ocean ________ are deep underwater troughs on the seafloor.
  8. 17. As we get closer to land, the age of the seafloor gets ________.
Down
  1. 1. These isochron maps revealed an interesting ________.
  2. 2. Seafloor ________ is the process by which new oceanic crust continuously forms along mid-ocean ridges and is destroyed at ocean trenches.
  3. 4. There are vast ________ ranges deep below the ocean's surface called mid-ocean ridges.
  4. 6. The theory of plate ________ states that Earth's surface is made of rigid slabs of rock, or plates, that move with respect to each other.
  5. 7. An echo sounder produces sound ________ that travel from a ship to the seafloor and back.
  6. 9. The ________ part of the ocean is in the middle, shown in red.
  7. 11. When magma erupts onto Earth's surface it is called ________.
  8. 13. Because tectonic ________ move very slowly, most changes to Earth's surface take a long time.
  9. 16. Tectonic plates move very ________, only 1.9 cm per year.