| A | B |
|---|
| Continental drift | theory that the continents were once a single landmass |
| Alfred Wegener | First stated the Theory of Continental Drift |
| Pangaea | Single, giant landmass of the continents |
| Mid-ocean ridge | under water mountain range |
| Rift valley | area between two ridges that formed by divergent or spreading plates |
| Seafloor spreading | process that forms new crust |
| Trench | deep canyon formed by a subducting plate |
| Subduction zone | place where old oceanic crust is forced back down into the mantle |
| Theory of plate tectonics | the Earth's crust is broken into plates that float on the upper part of the mantle |
| Convection current | movement of a gas or liquid caused by changes in temperature |
| Plate boundary | place where 2 plates meet |
| Magma chamber | underground pocket of molten rock |
| Hot spot | place where magma reaches the surface of a tectonic plate |
