SES4U
Unit 3 – Recording Earth’s Geological History
Formation of the Crust, Continents, Atmosphere, and Oceans – Worksheet
Name: _____________________________
Instructions
Use your textbook and various Internet resources to answer the following questions about the formation of the crust
and continents.
When you are finished, email your responses and pictures in a single document to Mr. Oest.
Please read pages 623-632 to find most of the answers to the questions below.
Questions requiring pictures are written in blue.
Formation of the Crust
1. What is differentiation?
2. What are the differentiated zones of Earth? Use the Internet to find a picture of the differentiated zones of
Earth.
3. Compare the proportions of elements in the Earth’s crust with the proportions of these elements in the Earth
as a whole. What explains this difference?
4. What became of the Earth’s earliest crust?
5. What material makes up much of the crust that forms Earth’s continents today?
6. What is a craton? How is it like a continent’s root?
7. What is a Precambrian shield? What do we call the Precambrian shield in North America? Find an image of
the Precambrian shield in North America.
Growth of the Continents
8. What is an orogeny? How are they related to the formation of land masses?
9. Why is there little evidence of Proterozoic orogenies today?
10. How and when was Laurentia formed?
11. What was the name of the first supercontinent? When did it form? Find an image of this supercontinent.
Formation of the Atmosphere
12. When and how did the atmosphere begin to form?
13. How did volcanic outgassing contribute to the formation of the Earth’s early atmosphere?
14. In the Hadean and early Archean eons, there was little oxygen in the atmosphere. Where did the oxygen gas
come from?
15. What are stromatolites and how were they important to the formation of Earth’s early atmosphere? Find a
photo of present-day stromatolites.
16. Explain how scientists conclude that ancient cyanobacteria produced oxygen.
17. How are scientists able to determine whether there was oxygen in Earth’s early atmosphere by looking at
rocks?
18. What are banded-iron formations? What are red beds?
19. Provide two reasons as to why oxygen is an important gas in the atmosphere.
Formation of the Oceans
20. When do scientists think the World’s oceans formed? How did this likely occur?
21. How was rain important in the formation of oceans?
22. If asteroids brought 1cm of water to Earth every 50,000 years, and the average depth of the Earth’s oceans
is 3700m, how many years would it take to fill the ocean basins from this source?