| Term | Definition |
|---|---|
| Crust | The thin and soild outermost layer of the earth above the mantle. |
| Mantle | The layer of rock between the earths crust or core |
| Core | The central part of the earth below the mantle. |
| Lithosphere | The solid, outer layer of the earth that consists of the crust and the rigid upper part of the mantle. |
| Asthenosphere | The soft layer of the mantle on which the tectonic plates move. |
| Mesosphere | The strong, lower part of the mantle between the asthenosphere and the outer core. |
| Tectonic plate | A block of lithosphere that consists of the crust and the rigid, outermost part of the mantle. |
| Continental drift | The hypothesis that states that continents once formed a single landmass, broke up, and drifted or their present locations. |
| Sea~floor spreading | The process by which new oceanic lithosphere forms as magma rises toward the surface and solidifies. |
| Plate tectonics | |
| The theory that explains how large pieces of the earths outermost layer, called tectonic plates, move and change shape | |
| Convergent boundary | The boundary formed by the collision of two lithosphere |
| Divergent boundary | The boundary between two tectonic plates that are moving away from each other. |
| Transform boundary | The boundary between tectonic plates that are sliding pst each other horizontally. |
| Compression | Stress that occurs when forces act to squeeze an object |
| Tension | Stress that occurs when forces act to stretch an object |
| Folding | The bending of rock layers due to stress |
| Fault | A break in a body of rock alone which one block slides relative to another |
| Uplift | The rising of regions of the earths crust to higher elevations |
| Subsidence | The sinking of regions of the earths crust to lower elevations |