click below
click below
Normal Size Small Size show me how
Plate Tectonics
Unit 4 Plate Tectonics
Term | Definition |
---|---|
Tectonic/Crustal plates | Large, moving pieces of Earth’s lithosphere that rest on the asthenosphere |
Tectonic/Crustal plates | Commonly carries both oceanic and continental crust |
Continental Drift | A hypothesis made by Alfred Wegener in 1912 |
Continental Drift | Continents were once joined together but moved apart over time |
Pangaea | Supercontinent that included all of the landmasses on Earth; began breaking apart about 200 million years ago |
Plate Tectonics | Theory that pieces of Earth’s lithosphere are in constant motion, driven by convection currents in the mantle |
Divergent Boundary | Boundary along which two tectonic plates move away from each other |
Divergent Boundary | The sea floor spreads apart and new crust is formed |
Convergent Boundary | Boundary along which two tectonic plates move toward each other |
Convergent Boundary | Characterized by subduction or continental collision |
Convergent Boundary | Crust is usually destroyed |
Transform Boundary | Boundary along which two tectonic plates scrape past each other |
Transform Boundary | Characterized by earthquakes; crust isn’t created or destroyed |
Hot spot | An area where a column of hot material rises from deep within the mantle. -Lithosphere above is heated, causing volcanic activity at the surface |
Subduction | The process by which denser crust sinks beneath less dense crust |
Rift valley | A deep valley formed as tectonic plates move away from each other at a divergent boundary |
Mid-ocean ridge | An underwater mountain range where new ocean crust is formed by volcanic activity along a divergent boundary |
Ocean basin | A great depression occupied by the ocean on the surface of the lithosphere |