Vocabulary: Plate Tectonics

Vocabulary: Plate Tectonics Vocabulary Word Definition 1. Tectonic/Crustal plates ­Large, moving pieces of Earth’s lithosphere that rest on the asthenosphere ­Commonly carries both oceanic and continental crust 2. Continental Drift ­A hypothesis made by Alfred Wegener in 1912 ­Continents were once joined together but moved apart over time 3. Pangaea ­Supercontinent that included all of the landmasses on Earth; began breaking apart about 200 million years ago 4. Plate Tectonics ­Theory that pieces of Earth’s lithosphere are in constant motion, driven by convection currents in the mantle 5. Divergent Boundary ­Boundary along which two tectonic plates move away from each other ­The sea floor spreads apart and new crust is formed 6. Convergent Boundary ­Boundary along which two tectonic plates move toward each other ­Characterized by subduction or continental collision ­Crust is usually destroyed 7. Transform Boundary ­Boundary along which two tectonic plates scrape past each other ­Characterized by earthquakes; crust isn’t created or destroyed 8. 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 9. Subduction ­The process by which denser crust sinks beneath less dense crust 10. Rift valley ­A deep valley formed as tectonic plates move away from each other at a divergent boundary 11. Mid­ocean ridge ­An underwater mountain range where new ocean crust is formed by volcanic activity along a divergent boundary 12. Ocean basin ­A great depression occupied by the ocean on the surface of the lithosphere