1. Types of Plate Boundaries Divergent Plate Boundaries Convergent Plate Boundaries Transform Faults

2. Divergent Plate Boundaries   Mid-ocean ridges form along divergent boundaries. Magma pushes continental crust up causing it to break apart. Plates begin to move apart in opposite directions causing crustal material to slump downward, creating a rift valley. See animation.. Click here!!

3. Divergent Plate Boundaries   A linear sea is formed as water fills in the valley. Through continued divergence, an ocean basin forms, creating an ocean. Ex: Red Sea See animation.. Click here!!

5. Red Sea

6. Divergent Plate Boundaries   Mid-ocean ridges have oceanic rises and oceanic ridges. –Oceanic rises  gently sloping due to a fast rate of spreading. Ex: East Pacific Rise

8. East Pacific Rise

10. Divergent Plate Boundaries   –Oceanic ridges  have steeper slopes due to a slower rate of spreading. Ex: Mid-Atlantic Ridge

11. Iceland and Mid-ocean Ridge

12. Convergent Plate Boundaries   Plates are pushed together Oceanic crust is subducted and absorbed into the mantle creating a subduction zone Produces a deep- ocean trench and volcanic arc.

13. Three types of Convergence Oceanic/ Continental (Fig 1) Creates a subduction zone Subduction creates a deep trench On the continental plate, a continental arc forms parallel to the trench. Ex: Cascade & Andes Mountains

14. The Andes

15. Cascade Mountains

16. Three types of convergence Oceanic/ Oceanic (Fig 2) –Subduction creates a deep trench. –As one oceanic plate subducts, a chain of volcanic mountains form, producing an island arc. Ex: Aleutian Islands & Mariana Trench

17. Aleutian Island Arc

18. Marianas Trench

19. Three types of convergence Continental/ Continental (Fig 3) –As two continental plates collide, they buckle, fold and push upward to produce a mountain range. Ex: Himalayas

20. Transform Faults/Boundaries Plates slide past one another along faults in the lithospheric plate Crustal material is neither created nor destroyed Ex: San Andreas Fault

21. San Andreas Fault

22. Hot Spots & Mantle Plumes Hot spots are areas of continued volcanic activity NOT associated with plate boundaries. Ex: Hawaiian Islands & Yellowstone National Park Hot spots are fueled by regions of rising molten rock called mantle plumes. (pg 62) Super volcano?????Super volcano Old Faithful

23. Convection Cells and Magma Plumes

24. Seamounts & Tablemounts Underwater volcanoes are called seamounts. As seamounts break the surface of the ocean, they may become islands. Over time, the seamount’s peak erodes away as the seamount subsides, eventually becoming a flat-top tablemount or Guyot.

25. Hawaiian-Emperor Seamount

26. Coral Reef Formation Fringing Reef: grow close to land, associated with active volcanic islands. Ex: Kurumba Island in the Maldives

27. Coral Reef Formation Barrier Reef: Linear or circular reefs separated from land by a lagoon of water. Ex: Great Barrier Reef

28. Coral Reef Formation Atoll: By this stage, the volcano is completely submerged. All that remains is the reef and a lagoon. Ex: Atafu in S. Pacific Click Me

30. The Big Picture

31. 1-Asthenosphere 2-Lithosphere 3-Hot spot 4-Oceanic crust 5-Subducting plate 6-Continental crust 7-Continental rift zone (young plate boundary) 8-Convergent boundary plate 9-Divergent boundary plate 10-Transform plate boundary 11-Shield volcano 12-Oceanic spreading ridge 13-Convergent plate boundary 14-Strato volcano 15-Island arc 16-Plate 17-Asthenosphere 18-Trench

32. And finally...