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Inside the Earth
Term | Definition |
---|---|
Crust | The outermost layer of the Earth. |
Mantle | The layer of the Earth between the crust and the core. |
Core | The layer of the Earth that extends from below the mantle to the center of the Earth. |
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 the continents once formed a single land mass, broke up, and drifted to 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 Earthâs outermost layer, called tectonic plates, move and change shape. |
Convergent Boundary | The boundary formed by the collision of two lithospheric plates. |
Divergent Boundary | The boundary between tectonic plates that are moving away from each other. |
Transform Boundary | The boundary between tectonic plates that are sliding past 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 along which one block slides relative to another. |
Uplift | The rising of regions of the Earthâs crust to lower elevations. |
Subsidence | The sinking of regions of the Earthâs crust to lower elevations. |