Plate Tectonics

3. Scientists who made the theory of seafloor spreading
6. Creator to the theory of Pangea
7. a current in a fluid that results from convection.
10. The theory that Earth's outer shell is divided into several plates that glide over the mantle
14. The upper layer of the earth’s mantle
17. When all the continents fell apart from each other
19. All Land
20. An elongated valley formed by the depression of a block of the earth's crust between two faults or groups of faults of approximately parallel orientation.

1. The rigid outer part of the earth
2. The upper part of the mantle is composed mostly of peridotite
4. Theory that seafloor is formed when magma is forced upward
5. The middle of the earth
8. The boundary where two plates come together
9. It is composed mostly of silicate rocks rich in magnesium and iron.
11. The boundary between two plates moving apart
12. Occur where two plates slide past one another in opposite or same direction
13. a large landform that stretches above the surrounding land in a limited area, usually in the form of a peak.
15. The area where one plate goes under another
16. The two sub-layers of the Earth that move and float and can cause earthquakes
18. A mountain that Explodes