Plate Tectonics

5. the amount per unit size.
6. is a large continuous extent of land.
7. someone who studies the history of Earth's rocks and fossils.
10. crash together with violent impact.
11. a rigid layer of the Earth's crust that is believed to drift slowly.
12. relating to or occurring or living in or frequenting the open ocean.
13. the circular motion of hot minerals being heated up and cooled down beneath Earth's crust.
15. relating to eruptions of gas and lava from the earth's crust.
17. any long ditch cut in the ground.
20. a solid inorganic substance occurring in nature.

1. a person with advanced knowledge of empirical fields.
2. The bottom of the sea or ocean.
3. an underwater mountain
4. one of the large landmasses of the earth.
8. pertaining to the structure or movement of the earth's crust.
9. The study of rocks and fossils and their history on Earth.
14. downward movement of the edge of a plate of the Earth's crust into the mantle beneath another plate.
16. rock that in its molten form issues from volcanos.
18. subject to or caused by an earthquake or earth vibration.
19. molten rock in the Earth's crust.