Horizon Tectonics

4. An area of the mantle that is warmer and thinner that liquid rock breaks through, can result in the creation of island chains.
6. The geologist who proposed that the continents were originally one super-continent.
7. The upper part of the mantle on which the tectonic plates "float".
9. The part of the Earth's surface that is below water and is more dense.
10. A boundary where the plates move towards each other.
11. The geologist who came up with the theory of sea-floor spreading.
13. the theory that surface of the earth is made up of individual pieces that are in constant motion.
17. The island nation that is splitting and growing as a result of being on top of a divergent boundary.
18. The part of the Earth's surface that is above water and is less dense.
19. When one plate, usually the denser one, slides underneath another plate, volcanos happen in these areas.

1. The circular distribution of volcanos around the Pacific Ocean.
2. A boundary where the plates move away from each other.
3. The deepest spot in all the oceans.
5. The name of the proposed super-continent that existed before the plates started moving.
8. The land form that is found in the middle of the ocean and is a result of sea-floor spreading.
12. Often the result of plates sliding past each other at a fault line.
14. A boundary where the plates slide past each other.
15. The general name for geologic rumblings.
16. The name of the rock that makes up most of the ocean floor.