| A | B |
|---|
| Continental drift | The continents were once connected as a single supercontinent, and slowly moved apart |
| Pangaea | The name Wegner gave to the supercontinent |
| Plate tectonics | The theory that the rigid lithosphere of Earth is divided into different sections that "float" along on top of the weaker mantle region |
| Plate | The segments of the lithosphere |
| Divergent boundary | Occur when two plates move apart |
| Convergent boundary | Occur when two plates move toward each other |
| Transform fault boundary | Occur when two plates grind past each other |
| Oceanic ridge | The elevated seafloor that develops along a divergent plate boundary |
| Rift valley | Deep faulted structures that occur at a divergent boundary between two landmasses |
| Seafloor spreading | The process by which plate tectonics produces new oceanic lithosphere |
| Subduction zone | Destructive plate margin where oceanic crust is being pushed down into the mantle by a second plate |
| Trench | The surface feature created at a subduction zone |
| Continental volcanic arc | Produced in part by the volcanic activity that is caused by the subduction of oceanic lithosphere under a continental plate |
| Volcanic island arc | A chain of small volcanic islands created by the subduction of oceanic plates under another oceanic plate |
| Paleomagnetism | Rocks that show the location of the magnetic poles at the time of their formation |
| Normal polarity | When rocks show the same magnetism as the present magnetic field |
| Reverse polarity | When rocks show opposite magnetism as the present magnetic field |
| Hot spot | A rising plume of mantle material is located below the crust, which melts the rock near the surface, allowing magma to move though |
| Convective flow | Warm, less dense material rises and cooler, more dense material sinks |
| Mantle plume | Hot plumes of rock that are the upward flowing arms in mantle convection |
