1. DO NOW Turn in Plate Tectonics Boundaries handout
Pick up notes sheet and Review #10.

2. LOOKING BACK…
Which is:
Convergent?
Transform?
Divergent?

4. Divergent Plates: Rift Valleys and Mid Ocean Ridge Transform Boundaries: Offset Geology
SES2. Students will understand how plate tectonics creates certain geologic features, materials, and hazards.
Distinguish among types of plate tectonic settings produced by plates diverging, converging, and sliding past each other.
b. Relate modern and ancient geologic features to each kind of plate tectonic setting.

5. PLATES, FAULTS, STRESSES AND LANDFORMS
Boundaries
Force
Stresses
Faults
Landforms
Convergent
Destructive
Compression
Reverse
Ocean Trenches and Mountains
Transform
Neutral
Shear
Slip-strike
Offset Geology
Divergent
Constructive
Tension
Normal
Rift Valleys and Mid-Ocean Ridges

6. DIVERGENT PLATE BOUNDARIES
Plate separates.
Tension stress
Normal fault
Landforms Created:
Rift Valleys
Fault-block Mountains
Mid-Ocean Ridges
Constructive Force – creates new plates where magma rises.

7. DIVERGENT BOUNDARIES: PLATES BREAK APART
Magma pools up under crust.
Heat trapped.
Crust is thin and weak.
Begins to pull apart.
Fault develops as crust breaks.

8. DIVERGENT BOUNDARIES: PLATES BREAK APART
Forms a rift.
Rifts make new divergent plate boundary.
Link to rift animation

9. BREAK UP OF PANGAEA Formed at end of Permian 225 million years ago.
A rift split Pangaea from east to west during the Triassic era (200 million years ago).
Created smaller continents Laurasia and Gondwanaland.

10. SUPERCONTINENT CYCLE Geologic cycle.
Continents merge and split repeatedly.
Continental collisions and break ups have occurred several times in Earth’s history.

11. National Geographic Video Link: The Early Earth and Plate Tectonics
SUPERCONTINENT CYCLE
Pangaea million years ago
Gondwanaland ~ 600 million years ago
Rodinia ~ 750 million to 1 billion years ago
Columbia (?) ~1.8 to 1.5 billion years ago
Kenorland (?) ~2.7 to ~2.1 billion years ago
Ur ~3 billion years ago
National Geographic Video Link: The Early Earth and Plate Tectonics

12. FUTURE EARTH Continents will move and change.
New supercontinents will form.
Notice Great Rift Valley in Africa….

13. DIVERGENT PLATES CREATE NEW CRUST: MID OCEAN RIDGES
Oceanic plates separate.
New crust in center.
Crust older farther from center.
Sediment builds up farther away from center.
Ridge builds up around fissure.

14. DIVERGENT OCEAN PLATES
Magma rises.
Pushes out as it rises.
Creates new sea floor.

15. DIVERGENT OCEAN PLATES
Cools and moves outward from central ridge.
Old crust collides with other plates and subducts.

16. MINERALS AT RIDGES Ocean crust is generally MAFIC rock.
Heavy metals such as Iron and Manganese.
Manganese nodules found on the ocean floor.
Sulfur and other minerals
build up at the ridge.

17. LANDFORMS CREATED: RIFT VALLEYS
Continental plates separate.
Forms depression on crust – valley.
Valleys created by tectonics rather than erosion.
Can create lakes, seas, hotspots and volcanoes.
Valleys also called grabens.

18. LANDFORMS CREATED: RIFT VALLEYS
Mountains: Fault-Block
Few continental Rift Valleys:
Great Rift Valley in Africa
Rhine Rift Valley in Germany
Non-Example: Grand Canyon caused by river erosion - NOT a rift valley.

19. PLATES, FAULTS, STRESSES AND LANDFORMS
Boundaries
Force
Stresses
Faults
Landforms
Convergent
Destructive
Compression
Reverse
Ocean Trenches and Mountains
Transform
Neutral
Shear
Slip-strike
Offset Geology
Divergent
Constructive
Tension
Normal
Rift Valleys and Mid-Ocean Ridges

20. TRANSFORM BOUNDARIES Plates move opposite relative to each other.
Shear force.
Slip-strike fault.
Neither creates or destroys crust – neutral.

21. LANDFORM FEATURES Offset Geology
Landforms displaced laterally (side to side).

22. EXAMPLE: SAN ANDREAS FAULT
Video Link: Violent Pacific: San Andreas Fault

23. SOMETHING TO THINK ABOUT
At what location is:
Old ocean crust subducting?
Magma spreading outward?
New ocean crust forming?
Magma rising? D B C A

24. ACTIVITY
Cut and Paste
Review #10