Download Part 2…Plate Tectonics

Plate Tectonics
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Preface and Historical Perspective
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When did the theory of Plate Tectonics originate?
How were people affected by tectonic activity?
What is a “plate” defined as?
What does the term “tectonic” mean?
What theory of land movement preceded the current theory of plate tectonics?
When did the super continent of Pangea first begin to break up? What did it ultimately form?
Who is the father of “uniformitarianism”?
What does this geologic principle state?
What early evidence was used to support the idea the continents have moved over time?
How was Alfred Wegener’s theory of continental drift received by the scientific community of
his time?
11. What happened to Wegener eventually?
Developing the Theory
1. How much of the earth’s surface is beneath the water?
2. What was the ocean bottom thought to be like in early times/
3. What technologic advances greatly improved our ability to envision the ocean bottom?
4. What is the mid ocean ridge system? What are its dimensions?
5. What interesting property did basaltic material on the ocean floor exhibit?
6. What accounted for zebra like magnetic striping that occurs on the ocean floor?
7. Scientists eventually concluded that the sea floor was spreading. Describe how this occurs.
8. How did oil drilling exploration confirm the idea of sea floor spreading?
9. What did the sea floor spreading theory suggest about the age of the ocean crust as one moves away
from the mid ocean ridge?
10. Where was the crust being destroyed as it was being created at the mid ocean ridge system?
11. Click on the earthquake zone maps. What do the boundaries seem to outline?
Part 2…Plate Tectonics
Divergent Boundaries
1. List the 4 major types of plate boundaries
2. What is the best known divergent boundary?
3. What is occurring at the mid ocean ridge system
4. Where would the oldest crust be found with respect to the mid Atlantic ridge? Youngest crust?
5. What is happening in Iceland?
6. What is happening in Saudi Arabia?
7. Where might the next ocean be originating today.
8. What may be the ultimate fate of Africa?
Convergent Boundaries
1. Where does recycling of older crust material occur?
2. What is a subduction zone?
3. What types of convergence can occur?
Ocean-Continental convergence
4. How are trenches produced?
5. How were the Andes Mountains being created?
6. What was the largest recent quake in South American history?
7. How are volcanoes produced by ocean/continent interactions?
Ocean-Ocean Convergence
8. What types of islands are produced by ocean plates converging?
9. List two island arcs produced in this manner.
Continent-Continent convergence
10. How were the
Himalayas created?
11. What is their maximum elevation?
12. What is the average elevation of the Tibetan Plateau?
13. How do they compare with European and American mountains?
Transform boundaries
14. What is a transform boundary?
15. What is the name of the fault zone slicing through California?
16. What two plates are involved in this fault zone?
17. Approximately how long is it?
Rates of Motion
1. How do scientists measure the rate of motions of a plate
2. If a plate is moving at 2.5 cm/year how far will it have moved in 50 million years? Clue (2.5 cm = one
inch)
3. What is geodesy?
4. How is GPS technology being used to measure rates of plate movement?
Hot Spots
1. How were the Hawaiian Islands formed?
2. Who first invented the idea of “hot spots”?
3. How is the shape of the Hawaiian island chain explained by the theory of hot spots?
4. How has Wilson’s theory been confirmed by dating of the islands from youngest to oldest.
5. Construct a diagram showing how the movement of a plate may produce an island chain.
6. About how many hot spots have been identified here on Earth?
7. How is Yellowstone National park related to the theory of hot spots?