Earth Structure & Plate Tectonics
Across
- 2. molten rock that has been expelled from the interior of the Earth
- 4. The thinnest earth layer and the only layer humans have ever dug
- 6. molten rock that is within the Earth
- 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.
- 9. Which of the earth layers mostly consists of iron and nickel?
- 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.
- 12. Geologic formations that form when plates collide and one is pushed under the other. The Mariana ------- is an example.
- 14. The middle layer of Earth's interior
- 15. Primary state of matter of Earth's outer core
- 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.
- 18. Geologic formations that form when plates collide and push upward
Down
- 1. The crust and the upper layer of the mantle together make up this zone of rigid, brittle rock
- 3. ____ occur when molten rock pushes up through weaknesses in the crust.
- 5. A ---- is a crack between tectonic plates. Earthquakes often occur there.
- 7. Earth's core is mostly made of this
- 9. Inner core radiates its heat by....?
- 11. A natural disaster that is caused by the movement of tectonic plates
- 12. Earth's crust is broken into pieces called ____ plates.
- 13. Primary state of matter of Earth's inner core
- 16. ____ rocks are made when molten rock cools down and solidifies.