1. Earth’s Interior and Plate Tectonics
Physical Science
Section 17.1

2. This is how the continents formed….

3. The Earth is like a parfait, it has layers
If you cut the earth in half, it would look very much like a parfait, with different layers and compositions based on density
The earth has three main layers, the crust, the mantle, and the core

4. The Crust We live on this layer Its is cool, and made of solid rock
Oceanic crust is thinner and denser than continental crust.
The crust is the least dense portion of the earth and only about miles thick

5. The Mantle Layer of rock that is denser than the crust
About 1800 miles thick
Outer mantle is solid rock
Inner mantle the rocks are extremely hot and bendable like gum (plastic)

6. The Core The center of the earth Made mostly of iron and nickel
The inner core is solid metal while the outer core is liquid metal

7. The Earth heats up with depth
At only 2 miles down the temperature increase to 120 F
The core is much hotter than the mantle
In the core, temperatures reach over 10,000 F

8. The earth heats up with depth
The earth gets warmer towards the core because it contains so many radioactive isotopes
These unstable isotopes are constantly breaking down, releasing huge amounts of energy, which in turn heat the earth

9. How do plates move?

10. Evidence #1: The Pangea Puzzle
In the 20th century, Alfred Wegener noticed that eastern S.America fits into western Africa
He also noticed that several of the other continents fit together like puzzle pieces
He also found that fossil evidence showed that several of the same organisms are found on continents now separated by oceans
He theorized that 250 million years ago all the continents combined to form the giant land mass he named pangea

11. How did this happen?
The earth’s outer shell, called the lithosphere is made of the crust and upper portion of the mantle.
This lithosphere is very rigid and consists of 7 large pieces and a few small ones that fit together like a puzzle
These large pieces are called tectonic plates

12. Plate Tectonics
These plates fit together like puzzle pieces and move in relation to each other
these plates move away, towards, or alongside each other
Tectonic plates move about 6 inches per year

13. Divergent   Plate Boundaries
In some areas, the plates move away from each other
When this occurs, hot liquid rock called magma rises and cools, forming new lithospheric rock

14. Convergent  Plate Boundaries
Less dense continental plate floats over more dense oceanic plate
This process is called subduction
As this more dense rock goes down into the mantle, it heats up and melts
The magma rises and pushes up the crust, forming volcanic mountains also earthquakes

15. Subduction - two plates meet, the more dense plate (oceanic crust), dives beneath the less dense plate (continental crust)

16. Continental vs. Continetal
Same density so no subduction
Builds non-volcanic mts.
Earthquakes

17. Oceanic vs. Oceanic Similar density, but subduction anyway
Earthquakes, trenches,
volcanic island arcs

18. Transform Fault Boundaries
These are areas where plates move along side one another
As plates move, they can cause cracks in the lithosphere called faults
As plates move along side each other at these faults, the plates cause a great deal of force and create earthquakes

19. RECAP  Divergent   Plate Boundaries Convergent   Plate Boundaries
Divergent means plates MOVE AWAY  from each other
Convergent   Plate Boundaries
Convergent means plates MOVE TOWARD   each other
Transform Fault Boundaries
areas where plates move along side one another
like this  or this 
 

20. Earth is made of 3 main layers
Crust- cool, thin, made of rock, miles thick
Mantle, denser than crust, 2500 miles thick, 80% of earth’s volume: inner mantle solid rock, outer mantle bendable gummy rock
Core- center of earth, made of iron and nickel, made of 2 layers: inner solid metal, outer liquid metal

21. Pangea- 250 million years ago all the continents combined to form the giant land mass called Pangea
Lithosphere (earth’s outer shell) is made of the crust and upper portion of the mantle.
lithosphere -very rigid and consists of 7 large pieces (called tectonic plates) and a few small ones that fit together like a puzzle

22. Plate Tectonics
These plates fit together like puzzle pieces and move in relation to each other
these plates move away, towards, or alongside each other
Tectonic plates move 6 inches per year

23. Evidence 2: Biogeographical

24. Final views