tectonic plates

1. sections of the earths crust that move due to convection currents.
4. proposed the theory of sea floor spreading.
6. the portion of earths crust that primarily contains basalt.
11. a usually light colored igneous rock found in the continental crust.
12. the process that creates new sea floor as plates move away from each other at the mid ocean ridges.
13. the portion of the earths crust that primarily contains granite, is less dense than oceanic crust, and is 20-50 km thick.
14. a German scientist who proposed the theory of continental drift.
15. the process by which oceanic crust sinks beneath a deep ocean trench and back into the mantle at a convergent boundary.

1. a theory stating that earths lithosphere is broken into huge plates that move and change in size over time.
2. a deep valley along the ocean floor through which oceanic crust slowly sinks towards the mantle in a process known as subduction.
3. the hypothesis that states that the continents once formed a single landmass.
5. the supercontinent containing all of earths land that existed about 225 million years ago.
7. a dark, dense, igneous rock with a fine texture, found in oceanic crust.
8. an undersea mountain chain where new ocean floor is produced created by a divergent plate boundary.
9. the area of magnetic force around a magnet.
10. the preserved remains or traces of an organism that lived in the past.