1. PLATE TECTONICS

2. Lithospheric plates
Lithosphere is made up of 12 large plates and about 20 smaller ones
Plates are solid and float on the asthenosphere
Convection currents in the asthenosphere make the plates move

5. Continental and Oceanic plates
Continental plates are usually less dense
Oceanic plates are under the ocean and made of more dense rock

6. Plate Boundaries There are 3 main types of plate boundaries:
Divergent ( moving apart)
Convergent (moving together)
Transform (moving past each other)

7. Divergent Boundaries On land - produce rift valleys
Under the ocean - mid-ocean ridges such as in the Atlantic
As the plates separate, magma rises into the space and hardens
Volcanoes and shallow earthquakes occur

13. Convergent boundaries
One plate may move under the other (subduction zone)
Deep earthquakes and volcanoes occur
Mountains form when one plate is pushed up

14. Types of convergent boundaries
Oceanic - oceanic: creates chains of islands (ex. Phillipines, Japan)

16. Oceanic - continental: oceanic plate subduct under continental plate; creates deep ocean trenches and coastal mountain ranges

18. Continental - continental: mountain ranges ex. Himalaya

21. Transform boundaries
Plates slide past each other causing fault lines and earthquakes
Ex. San Andreas Fault