Don’t Break Your Plate

1. Don’t Break Your Plate Notes on Plate Tectonics

2. Key Points • Plate tectonics accounts for several features on the earth’s surface • Seafloor spreading • Subduction zones • Earthquakes • Volcanoes • Mountain ranges • Plates move due to mantle convection

3. How do plates move? • The plates of the Earth float on top of the aesthenosphere • When mantle rock near the Earth’s core heats up it becomes less dense and rises while the cooler rock near the surface sinks—mantle convection • Moves plates a few centimeters each year

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5. Three types of plate boundaries: • Divergent • Transform • Convergent

6. Divergent Boundaries • New crust is created as two plates pull away from each other • If two oceanic plates, the ocean will grow wider—seafloor spreading • If two continental plates, creates a rift that will form two different land masses • Fills with water in the rift

7. Transform Boundaries • Two plates are sliding horizontally past one another • Sometimes known as faults • Earthquakes take place along these boundaries

8. Convergent • There are 3 types of convergent boundaries: • Oceanic-oceanic convergence • Continental-continental convergence • Oceanic-continental convergence • Crust is destroyed and recycled back into the Earth’s interior as one plate sinks below another plate—subduction zones • Mountains and volcanoes often form here

9. Oceanic-Oceanic Convergence • When one oceanic plate subducts under another: • A deep ocean trench is formed • Creates undersea volcanoes that over time, can build up to form volcanic islands

10. Continental-Continental Convergence • When two continental plates meet head-on, neither one subducts. • Plates tend to buckle and rise up/sideways to form mountain ranges • i.e. Himalayan Mountains

11. Oceanic-Continental Convergence • When an oceanic plate subducts below a continental plate: • The continental plate rises to form mountains • When oceanic plate sinks deep, some pieces break off and get locked in place—leads to earthquakes

12. Which of the following is not a plate boundary? • Divergent • Convergent • Transvergent • Transform 20

13. Where are mountains and volcanoes often found? 20 Seconds Remaining • Subduction Zones • Mid-ocean Ridge • Seafloor Spreading

14. Which of the following is NOT a type of convergent boundary? • Ocean-ocean • Continental-ocean • Continental-continental • Continental-sea 20

15. This type of boundary is two plates pulling away from each other to create new crust. • Convergent • Divergent • Transform 20

16. This boundary type has two plates sliding past each other 20 • Convergent • Divergent • Transform

17. This is where one plate sinks below another, melting back into the mantle. • Transform boundary • Subduction zone • Mid-ocean ridge • Divergent boundary 20

18. How do the tectonic plates move? • Convection currents in the mantle • Convection currents in the inner core • Conduction in the mantle 20