1. Earth Systems 3209
Unit: 1
Introduction to Earth Science – The Evolution of Planet Earth
Reference:
Chapters 1, 17 and Appendix A & B

2. Earth’s Interior Focus on . . . Unit 1: Topic 2.4
recognizing that Earth (Geosphere) has a layered Interior.
identifying the characteristics of each layer.
drawing a diagram representing Earth's interior.

3. Earth’s Interior
The model of Earth’s interior is based on indirect evidence.
The diagram to the left outlines four main layers inside of Earth.
Text Reference: pages &

4. Layers of Earth’s Interior
Lithosphere
Lithosphere
cool, rigid layer directly above the asthenosphere
approximately 100 km thick, which includes the entire crust and a portion of the uppermost mantle

5. Layers of Earth’s Interior
Crust
Crust (two types)
Continental Crust – 30 to 40 km thick and has low density
Oceanic Crust – approximately 5 km thick and has high density

6. Layers of Earth’s Interior
MOHO
Mohorovicic Discontinuity (Moho)
boundary separating the crust and the mantle
distinguished by an increase in rock density
velocity of seismic waves show an increase

7. Layers of Earth’s Interior
Asthenosphere
Asthenosphere (Upper Mantle)
hot, weak zone of rock that is capable of gradual movement. This is the layer that the crustal plates rest upon
located from approximately 100 km to 700 km in depth

8. Layers of Earth’s Interior
Lower Mantle
Lower Mantle
consist of high density rocks rich in compounds of iron, magnesium, and silicon
this layer is approximately 2200 km thick

9. Layers of Earth’s Interior
Outer Core
Outer Core
consist of liquid iron and nickel
approximately 2270 km thick
seismic waves (S-waves) do not pass through this layer

10. Layers of Earth’s Interior
Inner Core
Inner Core
consist of solid iron and nickel
approximately 1216 km thick

11. Temperature and Density Increases with Depth
Temperature inside Earth increases at a rate of approx. 35 degrees Celsius per kilometer.
This is referred to as the Geothermal Gradient.
Density inside Earth also increases as depth inside of Earth increases.

12. Example 1: Which layer of Earth’s structure is represented by “X”
asthenosphere
inner core
lithosphere
Outer core

13. Example 2: Which best describes continental crust?
7 kilometres thick; higher density than ocean crust
7 kilometres thick; lower density than ocean crust
35-40 kilometres thick; higher density than ocean crust
35-40 kilometres thick; lower density than ocean crust

14. Example 3:
Which is the correct sequence of Earth’s layers from the surface to the center? Surface Center (A) crust - inner core - outer core – mantle
(B) crust - mantle - outer core - inner core
(C) mantle - crust - inner core - outer core
(D) mantle - outer core - inner core - crust

15. Your Turn . . .
Take the time and complete the following questions (Solutions to follow)
Questions:
Draw a well labeled diagram outlining the layers of Earth.

16. Solutions . . .
Labelled Diagram of Earth’s Layers:

17. Your Turn . . .
Take the time and complete the following questions (Solutions to follow)
Questions:
Reference the next slide and answer the questions on the bottom of the slide.

18. Your Turn . . . Q. 1 Label each of the layers in the diagram above.
Density
Relative Temperature
Q. 1 Label each of the layers in the diagram above.
Q. 2 Fill in the relative temperature as “HIGH” or “LOW”.
Q. 3 Fill in the density as “HIGH” or “LOW”.

19. Solutions . . . 2.8 4.5 Questions: 9-10 13 Density
Relative Temperature
2.8
4.5
9-10 13
Questions:
LOW
LOW
HIGH
HIGH

20. Fill in the following Chart at Home!!
Inner Core
Outer Core
Lower Mantle
Asthenosphere
Crust
Materials (Composition)
State (s/l/g)
Density
Relative Temperature

21. Summary . . . Overview of Points covered: Earth’s layers include:
Crust (Continental & Oceanic), Upper Mantle (Asthenosphere), Lower Mantle, Outer Core, Inner Core
Temperature and Density both increase with depth inside of Earth