| A | B |
|---|
| crust | the outermost layer of the Earth |
| continental crust | makes up the continents, up to 70 km thick |
| oceanic crust | under the ocean floor, up to 8 km thick |
| mantle | layer beneath the crust |
| isostasy | The balance between the downward force of the crust and the upward force of the mantle |
| fossil | the preserved remains of an ancient organism |
| Continental Drift | idea proposed by Alfred Wegener |
| Pangaea | This single, giant landmass that was made of all the continents put together |
| mid-ocean ridges | a large system of underwater mountains |
| Ocean Floor Spreading | as either side of the ridge moves apart, lava escapes from the mantle |
| Trenches | a deep, V-shaped valley on the ocean floor |
| subduction | The process where the crust plunges into the mantle and melts |
| Plate Tectonics | the Earth’s surface consists of several plates that are in constant motion |
| lithosphere | The outermost solid part of the Earth |
| divergent boundary | plates move apart, creating new crust |
| convergent boundary | plates are coming together, causing one plate to sink |
| Transform Boundary | Two plates grind horizontally past each other |
| convection current | the movement of materials caused by differences in temperature |
| Deformation | the breaking, tilting, and folding of rocks due to stress |
| compression | rocks are squeezed together |
| tension | rocks are pulled apart |
| shearing | rocks are pushed in opposite directions |
| anticline | an upward fold |
| syncline | a downward fold |
| fault | A break or crack along which rocks move |
| rift valley | a section of rock between 2 normal faults slides down |
| plateau | A large, flat section of land that is raised high above sea level |
