1. Warmup
1. What geologic formation occurs where two oceanic plates are separating? (Where you have a divergent boundary)
HINT: The formation at slit B from yesterday’s activity

2. 7.1 Plate Tectonics

3. Layers of the Earth
by composition

4. by physical properties
Lithosphere- the outermost, rigid layer that is divided into pieces called tectonic plates
Asthenosphere- the plastic layer of the mantle on which pieces of the mantle move.
Mesosphere- strong, lower part of the mantle between the asthenosphere and the outer core.
Outer Core- the liquid layer of the Earth’s Core
Inner Core- a solid, dense center of our planet.

5. Continental Drift Africa & South America look like they fit together
similar fossils, rocks, and glacial striations
Alfred Wegner, 1915
The continents were once a super-continent called Pangea
the continents are plowing through the ocean floors

6. Plate Tectonics Oceanic plate- thin plate with high density
Earth's crust is made up of plates that ride on top of the asthenosphere
The plates move due to convection currents in the mantle
Oceanic plate- thin plate with high density
Continental plate- thick plate with low density

8. Plate Boundaries
Divergent plate boundary- the boundary formed from the separation of two lithospheric plates
O-O: mid ocean ridge
C-C: Rift Valley

9. Convergent plate boundary- the boundary formed from the collision of two lithospheric plates
O-O: volcanic island arc
O-C: volcanic arc
C-C: mountains

10. Transform plate boundary- the boundary formed from the sliding of two lithospheric plates past each other in opposite directions

11. Faults
Compression – the type of stress that occurs when an object is squeezed, such as when 2 tectonic plates collide.
Tension- the force (stress) that occurs when forces act to stretch an object.

12. Folding- the bending of rock layers due to stress
Two main types of folds:
Anticlines- upward arching folds
Synclines- downward
troughlike folds

13. Fault- the surface along which rocks break and slide past one another.
2 Main types of faults:
Normal faults- occur at divergent boundaries
Reverse faults- occur at convergent boundaries