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Plate Tectonics-6th
6th Grade Plate Tectonics
| Question | Answer |
|---|---|
| Tectonic plates | pieces of the lithosphere consisting of oceanic and continental crust |
| Lithosphere | Physical layer of Earth; consists of the crust and upper mantle; rigid, makes up tectonic plates |
| Asthenosphere | Upper mantle; plastic (solid magma that flows) |
| Inner Core | Solid, dense ball of iron and nickel |
| Outer Core | Liquid ball of iron and nickel |
| Crust | Compositional layer of Earth; outermost layer, thin, rigid |
| Mantle | Makes up 66% of Earth's mass (compositional layer) |
| Pangaea | All continents used to be connected in a supercontinent called Pangaea. |
| Sea-floor spreading | the process by which new oceanic lithosphere (sea floor) forms (magma rises to Earth's surface and solidifies at mid ocean ridges) |
| Continental drift | Wegener's idea that continents used to be connected but have since drifted apart |
| Convection | Hot magma rising and cool magma sinking constantly in the asthenosphere *** Causes the lithosphere to move*** |
| Convergent boundary | When tectonic plates collide (may form mountains, volcanoes) |
| Divergent boundary | When tectonic plates divide (may form mid-ocean ridges, rift valleys) |
| Transform boundary | When tectonic plates slide past each other (causes earthquakes) |
| Stress | Amount of force per unit area that is place on an object |
| Shear | Type of stress that pushes rock in different directions |
| Tension | Type of stress that pulls rock apart |
| Compression | Type of stress that pushes rock together |
| Subduction | When a more dense tectonic plate is pulled beneath another tectonic plate; occurs at convergent boundaries |
| Hot spots | a volcanically active area of Earth's crust that is NOT near a tectonic plate |
| Deformation | Rocks changing shape due to stress |
| Rift zone | an area of deep cracks that forms at a divergent boundary |
| Explosive eruption | Volcanic eruption that produces gas, ash, and pyroclastic material (very destructive) |
| Nonexplosive eruption | Volcanic eruption that produces lava flows |
| Boundary | area where two tectonic plates meet |
| Sea floor spreading provided evidence to support what theory? | Continental drift |
| Where do most earthquakes and volcanoes occur? | Tectonic plate boundaries |
| Fault | a break in Earth's crust |