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Unit 3 Vocab Erika H
Plate Tectonics
Term | Definition |
---|---|
Asthenosphere | Higher layer on the Earth's mantle, but still situated lower than the lithosphere. |
Subduction | Process where two tectonic plates collide the plate that is denser will descend below the less-dense plate. |
Seafloor Spreading | The theory that explains how new oceanic crust is formed at ocean ridges, slowly moved away from ocean ridges, and destroyed at deep-sea trenches. |
Mantle Convection | Convection currents in the mantle that are thought to be the main force of plate movements. |
Ridge Push | Tectonic process associated with convection currents in Earth's mantle that occurs when the weight of an elevated ridge pushes an oceanic plate towards a subsection zone. |
Slab Pull | Tectonic process associated with convection currents in Earth's mantle that occurs as the weight of the subducting plate pulls the trailing lithosphere into a subduction zone. |
Lava | Magma that flows out onto Earth's surface. |
Magma | Molten rock beneath Earth's surface. |
Tectonic Plate | Huge pieces of Earth's crust that covers its surface and fit together at their edges. |
Theory of Continental Drift | Wegener's theory that Earth's continents were joined as a single landmass, called Pangaea, that broke apart about 200 million years ago and slowly moved to their present locations. |
Convergent Boundary | Place where two tectonic plates are moving towards each other; is associated with trenches, islands arcs, and folded mountains. |
Divergent Boundary | Place where two of Earth's tectonic plates are moving apart; is associated with volcanism, earthquakes, and high heat flow, and is primarily found on the seafloor. |
Transform Boundary | Place where two tectonic plates slide horizontally past each other; is characterized by long faults and shallow earthquakes. |
Hot Spot | Unusually hot area in Earth's mantle where high-temperature plumes of mantle material rise toward the surface. |
Epicenter | Point on Earth's surface directly above the focus of an earthquake. |
Focus | Point of the initial fault rupture where an earthquake originates . |
Pangaea | Ancient landmass made up of all the continents that began to break apart about 200 million years ago. |
Geohazard | Geological/environmental state that can lead to large amounts of varying damage to the environmental. |
Reversal Fault | Compression causes vertical movement along a fault plane. |
Strike-Slip Fault | Shear causes horizontal movement along a fault plane. |
Normal Fault | Tension causes vertical movement downward along a fault plane. |
Compression | Stress that decreases the volume of a material. |
Tension | Stress that pulls a material apart. |
Shearing | Stress that causes material to twist. |
Felsic | Granite rocks that are light-colored. |
Mafic | Basaltic rocks that are dark-colored. |