1. Earth’s Dynamic Crust & Interior
NOTES

2. What’s inside the Earth?

3. How do we know what’s inside the earth?
Most of what scientists know about the Earth’s interior is inferred based on SEISMIC DATA
waves from earthquakes

4. The properties of the earth’s interior are inferred because
How do earthquake waves
tell us what’s in the earth?
The seismic waves travel at different speeds and at different angles through each layer due to refraction
The properties of the earth’s interior are inferred because
We’ve never been past the crust

5. The Layers Continental Crust— Oceanic Crust—
Crust—the outermost part of Earth just below the atmosphere or hydrosphere
Continental Crust—
thicker
less dense
mostly granite
Oceanic Crust—
thinner
more dense
composed of basalt

6. The Mantle Asthenosphere— Stiffer mantle—
The layer below the crust- broken into 2 sections
Asthenosphere—
Plastic mantle
Semi solid
Silly putty like
Stiffer mantle—
Solid part
Makes up 80% of earth’s mass

7. The Core
Outer core- believed to be a liquid because S-waves do not travel through it
Inner Core- believed to be a solid due to the extreme pressure

8. Page 10 of
your ESRt’s
Using this chart answer the ??’s on page 2 of your notes

9. What is the Theory of Continental Drift?

10. What is the Theory of Continental Drift?
Alfred Wegner, 1915
The continents were once a super-continent called Pangea
the continents are plowing through the ocean floors---most people didn’t believe this

11. What evidence supports this theory?
Africa & South America look like they fit together
similar fossils, rocks, and glacial striations

12. theory of Plate Tectonics theory of Continental drift?
How is the
theory of Plate Tectonics
different than the
theory of Continental drift?

13. What is the Theory of Plate Tectonics?
Earth's crust is made up of plates that ride on top of the asthenosphere

14. What evidence supports this theory?
distribution of earthquakes and volcanoes
sea-floor spreading
Marine fossils found on top of mountains
What’s Mr. Parr got to say??

15. What makes the plates move?
The plates move due to convection currents in the mantle
video

17. Let’s contrast and compare
Oceanic crust to
Continental crust

18. How do oceanic and continental crust compare with regard to thickness and density? (look at pg 10 of ESRT’s)
continental
oceanic
Density
(ESRTs
pg 10)
thickness
high
low
thin
thick

19. Let’s learn more
about these plates…

20. What are these types of plate boundaries?
What are the key
characteristics for each?
Give an example of where each can be found.

21. trenches, volcanoes, subduction
convergent boundary
trenches, volcanoes, subduction
Peru-Chile Trench

22. convergent boundary
mountain building
Himalayas

23. Two ocean crusts converging

24. transform fault
slide past one another
shallow earthquakes
San Andreas Fault

26. divergent plate boundary
new crust is made
Mid-Atlantic Ridge

27. Rifting on land

28. Sea floor spreading

29. How was
Hawaii formed??

30. Hot Spots Hot spots are found……
In the middle of plates
If there is a weak spot in the lithosphere, magma will be able to come through- click here

31. Formation of Hawaii

32. What happens to the age of oceanic crust as distance increases from a ridge?

34. the iron minerals align with the magnetic poles (magnetic north)
Explain how magnetic data can be used to show that oceanic crust is diverging at ridges. Use the diagram below to help explain your answer.
the iron minerals align with the magnetic poles (magnetic north)
same pattern on opposite sides of the ridge
proves sea-floor spreading