Plate Tectonics

3. There are matching rock formations in South America and this continent.
6. This supercontinent existed 250 million years ago.
7. The Earth's crust is thinnest and densest here.
10. The thickest layer of the Earth
11. This describes one plate moving under another plate, often producing volcanoes.
13. These types of current in the mantle are what makes plates move.
15. The San Andreas Fault in California is an example of this type of plate boundary.
16. Continental Drift Theory did not explain how the continents do this.
17. How many main layers is the interior of the Earth divided into?
18. Tectonic plates float on top of this.
20. The rigid part of the Earth including the crust and upper mantle (makes up the plates of the Earth)
21. The Mid-Atlantic Ridge is the result of this type of plate boundary.

1. This describes one plate crashing into another plate and pushes up mountains.
2. Harry Hess used this to map the bottom of the ocean and discovered the Mid-Atlantic Ridge.
4. Rigid but moving pieces of the Earth's surface are called _______ plates.
5. Who created Continental Drift Theory?
8. The thinnest layer of the Earth
9. Fossils of tropical plants were found here.
11. This type of spreading means the youngest rocks of the ocean floor are at divergent boundaries.
12. Earthquakes and volcanoes are usually located near the ______ between plates.
14. The Himalayan mountains are the result of this kind of plate boundary.
19. These happen when stress builds up at a plate boundary.