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Unit 3 Vocab
Plate Tectonics
| Term | Definition |
|---|---|
| Asthenosphere | The layer on top of Earth's mantle. |
| Subduction | Process by which one tectonic plate slips beneath another tectonic plate. |
| Seafloor Spreading | The hypothesis that new ocean crust is formed at mid-ocean ridges and destroyed at deep sea trenches it occurs in a continuation cycle of magma intrusion and spreading. |
| Mantle convection | A driving mechanism of plate movements. |
| Ridge push | Tectonic process associated with convection currents in Earth's mantle that occurs when the weight of an elevated ridge push an oceanic plate toward a suduction zone. |
| Slab pull | Tectonic process associated with convection currents in Earth's mantle that occurs when the weight of the subductiong plate pulls the trailing lithosphere into a subduction zone. |
| Lava | Magma that flows out into Earth's surface. |
| Magma | Slushy mix of molten rock and dissolved gases and mineral crystals. |
| Tectonic Plate | Large pieces of Earth's crust that cover its surface and fit together at the edges. |
| Theory of Continental Drift | Pangaea; how it drifted apart. |
| Convergent Boundary | Places where two tectonic plates are moving towards each other. Associated with trenches, island marks and folded mountains. |
| Divergent Boundary | Places where two of Earth's tectonic plates are moving apart. Associated with volcanism, earthquakes and high heat flow. It is found mainly found on the sea floor. |
| Transform Boundary | A region where two plates slide horizontally past each other. |
| Hot Spot | Hot regions of Earth's mantle. |
| Epicenter | Point on Earth's surface directly above the focus of an earthquake. |
| Focus | Point of the initial fault rupture where an earthquake originates that usually lies at least several kilometers beneath Earth's surface. |
| Pangaea | Ancient landmass made up of all the continents that began to break apart about 200 mya. |
| Geohazard | Natural disasters caused by Earth like landslides |
| Reverse Fault | A fault due to horizontal and vertical compression that squeezes rock and creates a shortening of the crust. |
| Strike- Slip Fault | A fault caused by horizontal shortening. |
| Normal Fault | Standard value for a location, including rainfall, wind speed, and temperatures, based on meteorological records complied for at least 30 years. |
| Compression | Stress that decreases the volume of a material. |
| Tension | Stress that pulls a material apart. |
| Shearing | Stress that causes material to twist. |
| Felsic | An igneous rock that is defined as a light colored rock. |
| Mafic | An igneous rock that is defined as a dark colored rock. |