CHAPTER 13 Concept Review
The Human Sphere: People and Rocks
1. What roles have Earth materials played in human history?
13.1 Minerals and Rocks: Building Earth’s Crust
2. What is a mineral?
3. What are the four mineral classes? Which is most common?
4. What are rocks composed of? In what two ways are rocks held together?
5. How is bedrock different from an outcrop? Where are outcrops found?
6. Within the context of the rock cycle, compare igneous, sedimentary, and metamorphic rocks.
7. Through what process are rocks recycled into the mantle?
8. Where does the energy needed to drive the rock cycle come from?
9. How does plate tectonics relate to the rock cycle?
13.2 Cooling the Inferno: Igneous Rocks
10. Describe the tectonic settings in which igneous rocks form.
11. In what two ways does mantle material melt into magma in the crust?
12. Give examples of igneous rock formations found beneath the surface. How are these subsurface features exposed at the surface through geologic time?
13. What is an igneous rock? How is an intrusive igneous rock different from an extrusive igneous rock?
14. Provide examples of igneous rock types.
15. Compare phaneritic igneous rocks with aphanitic igneous rocks with respect to where each forms. Give examples of each.
16. Compare felsic igneous rocks with mafic igneous rocks with respect to their silica content.
13.3 Layers of Time: Sedimentary Rocks
17. What is a sedimentary rock? How are sedimentary rocks formed?
18. What percentage of Earth’s crust is sedimentary rock? What percentage of the exposed crust is sedimentary rock?
19. Compare clastic, organic, and chemical sedimentary rocks in terms of how each is formed.
20. Give examples of depositional environments where sedimentary rocks form.
21. Provide examples of sedimentary rock types.
22. What kind of rock is coal? Describe how it forms. Describe petroleum and natural gas in the context of their importance to people.
23. What is mountaintop removal mining? Where is it practiced? How is it environmentally destructive?
24. How is salt formed? What kind of sedimentary rock is salt?
25. What are fossils? What information do fossils give us about Earth’s history and life?
13.4 Pressure and Heat: Metamorphic Rocks
26. What is metamorphism? Give two tectonic environments in which metamorphism occurs.
27. What are the two categories of metamorphic rocks? How do they differ in appearance?
28. What is a metamorphic rock protolith? Give examples.
29. Give several examples of metamorphic rocks.
13.5 Geographic Perspectives: Fracking for Shale Gas
30. What is fracking? What does this term stand for? Describe the steps in the technique of fracking.
31. What are the roles of water and chemicals in this procedure?
32. As of 2012, how many oil and gas wells were in use in the United States? What are the projected trends for use of shale gas in the coming decades?
33. What is fracking fluid, and why is it contaminated with toxins and radioactivity?
34. Give the pros and cons of fracking.