1. Plate Tectonics

2. Layers of the Earth Crust – Rocky outermost layer
Approximately 5-40 km
Includes the land surface and the ocean floor

3. Layers of the Earth Mantle – middle layer of hot rock
About 80% of Earth’s total volume
Lithosphere – rigid layer of crust in the upper mantle
Asthenosphere – soft layer below lithosphere
Almost 3,000 km thick

4. Layers of the Earth
Core – center which consists of the outer and inner core; made of iron and nickel
Outer core – molten (liquid-like) metal
Inner core – dense ball of solid metal; about 5,000oC

6. Some Facts to Know
The deeper you go towards the center of the Earth, the greater the temperature and pressure
Because scientists cannot study the Earth’s interior directly, they study and record how seismic waves travel through Earth

7. More Facts
Heat from the mantle and core cause convection currents, which are responsible for Earth’s magnetic field

8. More Facts
Forces beneath the surface are constantly changing Earth’s surface
TWO TYPES OF FORCES:
Constructive – build up land masses and mountains
Destructive – wear away mountains and features

9. Plate Tectonics
States that pieces of Earth’s lithosphere (plates) are in constant slow motion, driven by convection currents in the mantle
As the plates move, they collide, pull apart, and grind past each other
Move at a very slow rate: about 1-10 cm per year

10. Boundaries Where the plates in the lithosphere meet
Three main types of boundaries
Transform – two plates slip past each other in opposite directions
Where earthquakes occur

11. More Boundaries 2. Divergent – plates move apart (diverge)
Rift valleys form
3. Convergent – plates come together (converge)
Collision occurs when the two plates collide; the density of the plate determines which one comes out on top
Can cause mountain building

12. Deformation Stress in rock leads to three types of deformation…
Shearing: pushes in two opposite direction
Tension: pulls on rock making it thinner in the middle
Compression: squeezes rock together making it thicker in the middle

13. Faults Breaks in the Earth’s crust where plates slip past each other
Three main types:
Strike-slip
Normal
Reverse

14. Strike-slip Fault Caused by shearing
Rocks slip past each other with little up or down motion

15. Normal Fault Caused by tension
Fault is at an angle so half the rock lies above (hanging wall) while the other lies below

16. Reverse Fault Caused by compression
Same structure as normal fault, but blocks move in opposite direction

17. Boundary
Stress
Fault
Movement
Transform
Shearing
Strike-slip
Divergent
Tension
Normal
Convergent
Compression
Reverse