Tectonic Plate Crossword

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Across
  1. 5. ("all land") the single huge supercontinent that existed 245 million years ago, when all of Earth's continents were joined together.
  2. 7. changed in form or character without becoming something else
  3. 8. the southern continent formed when Pangaea split into two pieces
  4. 9. a single thickness of some substance or material
  5. 10. a system of connected underwater mountain ranges that run throughout the world's oceans. There is a rift valley in the center of the mid-ocean ridge, where magma rises up from the mantle, and pushes out to either side, producing seafloor spreading.
  6. 11. a large continuous extent of land
  7. 13. a vent in the earth's crust through which lava, steam, ashes, etc., are expelled
  8. 15. the process by which new oceanic crust forms when magma rises up and solidifies at the mid-ocean ridges. The newer crust pushes the older crust out to each side, which is why the age of the sea floor increases with distance away from the mid-ocean ridges.
  9. 16. reduce or cause to be reduced from a solid to a liquid state
  10. 17. crash together with violent impact
  11. 19. the rigid, brittle layer made up of the crust and the uppermost part of the mantle. It is broken up into pieces called tectonic plates.
  12. 20. the sudden occurrence of a violent discharge
Down
  1. 1. where two tectonic plates slip past each other, moving in opposite directions
  2. 2. molten rock in the earth's crust
  3. 3. plates large pieces of the lithosphere that slowly move on top of the asthenosphere. There are seven primary plates and many smaller ones. The seven primary plates are the African Plate, Antarctic Plate, Eurasian Plate, Indo-Australian Plate, North American Plate, Pacific Plate, and South American Plate
  4. 4. where two tectonic plates move away from each other
  5. 6. convection currents in the mantle that occur because hot rock in the lower part of the mantle is less dense and rises, and cooler rock in the upper part of the mantle cools, becomes more dense, and sinks. Mantle convection is thought to be the mechanism driving the movement of tectonic plates.
  6. 12. the process by which one tectonic plate sinks below another, returning to the mantle, where the rock is re-melted. Subduction takes place at convergent plate boundaries. Oceanic crust, which is denser, will always subduct under the less dense continental crust.
  7. 14. where two tectonic plates move toward each other
  8. 18. rock that in its molten form issues from volcanos