Horizon Plate Tectonics

2. The island nation in the north Atlantic where a rift valley can be observed.
5. The last name of the scientist who came of with the theory of continental drift.
7. How geologists refer to a volcano that seems to be asleep.
8. A place where two tectonic plates come together and sometimes form a mountain range.
10. The type of rock that makes up most of the oceanic crust.
12. When a portion of more-dense (usually oceanic) crust sinks under a less-dense portion of the Earth's crust.
13. The process that glues together particles of sediment.
15. A place where two tectonic plates slide past each other sideways.
16. Fossils of this fern-like plant were found on five different continents and help support the theory of continental drift.
17. The layer of the Earth's mantle on which the lithosphere floats.
19. The transfer of heat between two objects that are touching.
21. The type of heat transfer that occurs in the Earth's mantle.

1. A place where two tectonic plates move away from each other.
3. Vibrations that travel through Earth.
4. The shaking that results from a sudden shift in a transform boundary.
6. The name of the supercontinent thought to exist about 250 million years ago.
8. The idea that the continents move slowly across the Earth's surface.
9. The layer of rock that forms the outer surface of the Earth.
11. Molten rock that is found under the surface of the Earth.
14. The process that breaks rock down into sediment using the forces of wind, water and gravity.
18. A weak spot in the Earth's crust where magma has come through the surface.
20. The amount of mass in a specified amount of a substance.