1. Plate Tectonics

3. Plate Boundaries Causes of Plate Tectonics

4. What is Plate Tectonics  The Earth’s crust and upper mantle are broken into sections called plates  Plates move around on top of the mantle like rafts

6. What is the Lithosphere?  The crust and part of the upper mantle = lithosphere  100 km thick  Less dense than the material below it so it “floats”

7. What is the Asthenoshere?  The plastic layer below the lithosphere = asthenosphere  The plates of the lithosphere float on the asthenosphere

9. Questions...  What is the theory of plate tectonics?  What is the asthenosphere?

10. 2 Types of Plates  Ocean plates - plates below the oceans  Continental plates - plates below the continents

11. Plate Boundaries

12. Divergent Boundaries  Boundary between two plates that are moving apart or rifting    RIFTING causes SEAFLOOR SPREADING

13. Divergent boundary of two continental plates. Creates a __________. Example: _____________ rift valley East African Rift

14. Features of Divergent Boundaries  Mid-ocean ridges  rift valleys  fissure volcanoes  subduction zone called a TRENCH

20. Convergent Boundaries  Boundaries between two plates that are colliding    There are 3 types…

21. Type 1  Ocean plate colliding with a less dense continental plate  Subduction Zone: less dense plate slides under the more dense plate  VOLCANOES occur at subduction zones

23. Andes Mountains, South America

24. Convergent boundary of an oceanic plate and a continental plate. Forms a _______ mountain range and a ______. Examples: _______ or _______ Mts volcanic trench Cascades Andes

25. Type 2  Ocean plate colliding with another ocean plate  VOLCANOES occur at subduction zones

27. Aleutian Islands, Alaska

28. Convergent boundary of two oceanic plates. Creates an ________ and a _____. Example: _____ island arctrenchJapan

29. Type 3  A continental plate colliding with another continental plate  Have Collision Zones:  mountains form.

32. Convergent boundary of two continental plates. Forms a ______ mountain range. Examples: ___________, Alps, ______________ folded Himalayas Appalachians

33. Transform Fault Boundaries  Boundary between two plates that are sliding past each other  EARTHQUAKES along faults

35. San Andreas Fault, CA

36. Transform-fault boundary where the North American and Pacific plates are moving ____ each other. Example: ________________ in California past San Andreas Fault

37. Diagrams

38. Questions...  What are the three types of boundaries?  What direction do plates go for each?  Which boundary has a subduction zone…what occurs at a subduction zone?

40. Plate Boundaries Review  Places where plates move apart are called _____________ boundaries.  When continental plates diverge a ___________ is formed.  When two oceanic plates converge what is created? _____________________  The Appalachians formed mainly from continental plate collisions and therefore are a __________ mountain range.  The force moving the plates is ________________. Convection currents divergent rift valley an island arc and a trench folded

41. Causes of Plate Tectonics

42. What cause plates to move? Convection Currents  Hot magma in the Earth moves toward the surface, cools, then sinks again.  Creates convection currents beneath the plates that cause the plates to move.

44.  The less dense plate slides under the more dense plate creating a subduction zone called a TRENCH

45.  Subduction Zone: where the less dense plate slides under the more dense plate  VOLCANOES occur at subduction zones

46. Explain Pangaea

47.  This is what type of boundary ?

48. What are the two types of plates?

49. Divergent plate boundaries move_______

50. Tectonic plates move only _______ per year A. Kilometers B. Miles C. Centimeters D. Millimeters

51. This type of plate movement can result in the formation of mountains and/or volcanoes

52. What is the lithosphere?

53. Two transformative plates slide past each other. What geological event is likely to occur?

54. Questions...  How is a convection current formed?

55.  What are the three types of plate boundaries?

56.  What causes plates to move?