Earth Structure & Plate Tectonics

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Across
  1. 2. molten rock that has been expelled from the interior of the Earth
  2. 4. The thinnest earth layer and the only layer humans have ever dug
  3. 6. molten rock that is within the Earth
  4. 8. Tectonic plates move because of convection currents in the Earth’s mantle. These are driven by the ____ produced by the decay of radioactive elements inside the Earth.
  5. 9. Which of the earth layers mostly consists of iron and nickel?
  6. 10. A thin layer of Earth, about 150 miles thick, at the border between the mantle and the crust. It is very hot and nearly a liquid.
  7. 12. Geologic formations that form when plates collide and one is pushed under the other. The Mariana ------- is an example.
  8. 14. The middle layer of Earth's interior
  9. 15. Primary state of matter of Earth's outer core
  10. 17. Alfred Wegener proposed this theory at the beginning of the last century. It states that the continents were once all together in one land mass.
  11. 18. Geologic formations that form when plates collide and push upward
Down
  1. 1. The crust and the upper layer of the mantle together make up this zone of rigid, brittle rock
  2. 3. ____ occur when molten rock pushes up through weaknesses in the crust.
  3. 5. A ---- is a crack between tectonic plates. Earthquakes often occur there.
  4. 7. Earth's core is mostly made of this
  5. 9. Inner core radiates its heat by....?
  6. 11. A natural disaster that is caused by the movement of tectonic plates
  7. 12. Earth's crust is broken into pieces called ____ plates.
  8. 13. Primary state of matter of Earth's inner core
  9. 16. ____ rocks are made when molten rock cools down and solidifies.