Plate Tectonics

4. an opening in Earth’s crust from which lava, gas, and ash erupt.
7. the movement of plates that make up Earth’s surface.
9. boundary between plates that are moving toward each other.
11. a time when Earth was very cold and large areas were covered by glaciers.
13. boundary between plates that are moving away from each other.
14. a rigid section of Earth’s crust that moves very slowly.
15. the layer of Earth between the crust and the core.
16. Continental ________ is the theory that the continents are moving very slowly proposed by Alfred Wegener in 1915.

1. a convergent boundary where one plate is sliding beneath another
2. the rigid upper layer of the Earth.
3. an ancient supercontinent that scientists believe existed from about 200 to 300 million years ago.
5. layer of the upper mantle in which rocks can deform like plastic.
6. a large, slowly moving body of snow and ice.
8. the remains, traces, or imprint of an ancient living thing preserved in rock.
10. shaking and vibration of Earth’s surface.
12. a boundary between plates that are sliding past one another.