1. Bellringer Make your voc foldable Homework: Illistrations
Essential book page 68-76

3. Bellringer
Match your voc words
Homework:
Finish handout

4. 8-3.6 Explain how the theory of plate tectonics accounts for the motion of the lithospheric plates, the geologic activities at the plate boundaries, and the changes in landform areas over geologic time.

5. It is essential for students to know that the theory of plate tectonics explains why and how large sections of Earth’s crust, called lithospheric plates, move. A hypothesis of continental drift was developed before the present theory of plate tectonics. It was based on continent shape, fossil evidence, rock, and climate clues. This hypothesis later led to the theory of plate tectonics when evidence was found as to why the plates could move. Plate tectonics explains how many Earth features form.

6. Motion of the Lithospheric Plates
• Plates float on the upper part of the mantle.
• Convection currents can cause the asthenosphere to flow slowly carrying with it the plates of the lithosphere.
• This movement of plates changes the sizes, shapes, and positions of Earth’s continents and oceans.

7. Geologic Activities at Plate Boundaries
Divergent boundary—where two plates are moving apart
• most located along mid-ocean ridge (sea-floor spreading);
• new crust forms because magma pushes up and hardens between separating plates.

8. Convergent boundary—where two plates come together and collide
• activity depends upon the types of crust that meet;
• more dense oceanic plate slides under less dense continental plate or another oceanic plate – subduction zone, some crust is destroyed;
• two continental plates converge, both plates buckle and push up into mountain ranges;

9. Transform boundary—where two plates slide past each other
• crust is neither created nor destroyed;
• earthquakes occur frequently along this type of boundary.

10. Changes in Landform areas over Geologic Time
• Plates move at very slow rates – from about one to ten centimeters per year;
• At one time in geologic history the continents were joined together in one large landmass that was called Pangaea.
• As the plates continued to move and split apart, oceans were formed, landmasses collided and split apart until the Earth’s landmasses came to be in the positions they are now;

11. • Evidence of these landmass collisions and splits comes from fossils, landform shape, features, and rock structures, and climate change;
• Landmass changes can occur at hot spots within lithospheric plates;
• Earth’s landmasses will continue to move and change during the geologic time of the future.

12. Bellringer Make foldable of new voc words in your isn
Homework: make sure essentials book is up to date p 1-28,68-76,
Draw illistrations

13. quiz Convergent Oceanic to oceanic Subduction Zone volcano
Cont to cont
Fold and thrust
Cont to ocea
Nic
TRENCH
Divergent
RIFTING causes SEAFLOOR SPREADING
Transform
earthquakes

14. 8.3-6
Explain how the theory of plate tectonics accounts for the motion of the lithospheric plates, the geologic activities at the plate boundaries, and the changes in landform areas over geologic time.

15. Theory of Plate Tectonics
Plate Boundaries
Causes of Plate Tectonics

16. Plate Tectonics

17. 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

18. Plates
Plates move at very slow rates – from about one to ten centimeters per year

20. Pangaea
At one time in geologic history the continents were joined together in one large landmass that was called Pangaea

22. As the plates continued to move and split apart, oceans were formed, landmasses collided and split apart until the Earth’s landmasses came to be in the positions they are now;

23. Motion of the Lithospheric Plates

24. 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”

25. Motion of the Lithospheric Plates
Plates float on the lower part of the mantle.
This movement of plates changes the sizes, shapes, and positions of Earth’s continents and oceans.

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

28. 2 Types of Plates
Ocean plates - plates below the oceans
Continental plates - plates below the continents

29. Plate Boundaries

30. Divergent boundary Where two plates are moving apart;
most located along mid-ocean ridge (sea-floor spreading);
new crust forms because magma pushes up and hardens between separating plates.

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

32. Features of Divergent Boundaries
Mid-ocean ridges
rift valleys
fissure volcanoes

36. Convergent boundary Where two plates come together and collide;
activity depends upon the types of crust that meet;
more dense oceanic plate slides under less dense continental plate or another oceanic plate – subduction zone, some crust is destroyed;
two continental plates converge, both plates buckle and push up into mountain ranges;

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

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

40. Andes Mountains, South America

41. Type 2 Ocean plate colliding with another ocean plate
The less dense plate slides under the more dense plate creating a subduction zone called a TRENCH

43. Aleutian Islands, Alaska

44. Type 3 A continental plate colliding with another continental plate
Have Collision Zones:
a place where folded and thrust faulted mountains form.

47. Transform boundary Where two plates slide past each other;
crust is neither created nor destroyed;
earthquakes occur frequently along this type of boundary.

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

50. San Andreas Fault, CA

51. Evidence of these landmass collisions and splits comes from fossils, landform shape, features, and rock structures, and climate change

52. Changes in Landform areas over Geologic Time
Landmass changes can occur at hot spots within lithospheric plates;
Earth’s landmasses will continue to move and change during the geologic time of the future.

53. Causes of Plate Tectonics

54. 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.

55. Convection currents
deep inside Earth can cause the asthenosphere to flow slowly carrying with it the plates of the lithosphere.