1. Plate Tectonics

2. Ocean Topography
Ocean Ridges- underwater mountains; longest mountain range on Earth
Trenches- Narrow depression in the seafloor
How do they form?

3. Seafloor Spreading Seafloor spreading: when new ocean crust is formed
Formation of new crust
Magma is forced towards the surface
As the ridge separates the magma fills
the gap created
This will continue to happen and new
ocean crust will continue to generate

4. Plate Tectonics
Plates: huge, mobile pieces of crust that cover the Earth.
Move because of convection currents
Energy (thermal) comes from the core (internal) to drive plate movement.
There are 3 types of plate boundary

5. Divergent Boundaries
Divergent Boundaries- two tectonic plates move apart
Occur in Ocean ridges
Seafloor spreading

6. Convergent Boundaries
Convergent Boundaries: 2 tectonic plates move towards one another
When 2 plates collide the denser plate descends below the other plate
This process is called subduction
There are 3 types of convergent plate interaction…

7. Convergent Boundaries
Oceanic-Oceanic:
Forms an ocean trench
Oceanic-Continental:
Oceanic plate is more dense so it is subducted. Produces trenches & volcanic arcs
Continental-Continental
The crust are unable to subduct due to rocks so the continents collide and form massive mountain regions.

8. Convergent Boundaries1 2 3

9. Transform Boundaries Transform Boundaries Plates slide horizontally
Responsible for most earthquakes
Ex. San Andreas Fault

10. Look at California… What is so interesting?
Transform boundary at the San Andreas Fault

11. Free Template from www.brainybetty.com
Know Your Boundaries!!
7/16/2019
Free Template from

12. Lithosphere divided into 10 major tectonic plates— know the continental ones and the Pacific plate!

13. Plate Movement