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Chapter 11LectureOutline

Learning OutcomesAfter studying this chapter, you should be able to answer the following questions:

• What is coal-bed methane? Why is it both important and controversial?

• How do continental and oceanic crust differ?• Why do volcanoes occur?• What are some of the environmental and social

costs of mining and oil- and gasdrilling?• What are some solutions to those costs?• How can we reduce our consumption of geologic

resources?• Why is mass wasting a problem?

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When we heal the earth, we heal ourselves.–David Orr

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11.1 Earth Processes ShapeOur Resources

• Every one of us shares the benefits of geologic resources.

• Right now you are probably wearing several geologic products: – plastics, including glasses and synthetic fabric, are made

from oil;– iron, copper, and aluminum mines produced your snaps,

zippers, and the screws in your glasses; silver, gold, and – diamond mines may have produced your jewelry.

• All of us also share responsibility for the environmental and social devastation that often results from mining and drilling.

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Earth is a dynamic planet

• The core is composed of a dense, intensely hot mass of metal—mostly iron.

• Mantle surrounds the molten outer core, is a hot, pliable layer of rock.

• Crust is the outermost layer of the earth.

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Map of tectonic plates

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Plate tectonic movement

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11.2 Minerals and Rocks

• A mineral is a naturally occurring, inorganic solid with a specific chemical composition and a specific internal crystal structure.

• A rock is a solid, cohesive aggregate of one or more minerals.

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The rock cycle

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The rock cycle creates and recycles rocks

• Igneous rocks (from igni, the Latin word for fire) are solidified from hot, molten magma or lava.

• Metamorphic rocks form from the melting, contorting, and recrystallizing of other rocks.

• Sedimentary rocks are formed when loose grains of other rocks are consolidated by time and pressure.

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Weathering and sedimentation

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11.3 Economic Geologyand Mineralogy

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11.4 Environmental Effectsof Resource Extraction

• Half the coal used in the United States comes from strip mines.

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11.5 Conserving Geologic Resources

• Conservation offers great potential for extending our supplies of economic minerals and reducing the effects of mining and processing.

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11.6 Geologic Hazards

• Earthquakes, volcanoes, floods, and landslides are normal earth processes, events that have made our earth what it is today.

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Earthquakes are frequent and deadly hazards

• The 2004 earthquake and tsunami in Banda Aceh, Indonesia, stunned the world, killed over 230,000 people, and caused damage as far away as Africa.

• Less than a year later, an earthquake in Pakistan killed 80,000 people.

• Earthquakes are sudden movements in the earth’s crust that occur along faults (planes of weakness), where one rock mass slides past another one.

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Volcanoes eject deadly gases and ash

• Volcanoes and undersea magma vents are the sources of most of the earth’s crust.

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Floods are part of a river’sland-shaping processes

• Like earthquakes and volcanoes, floods are normal events that cause damage when people get in the way.

• As rivers carve and shape the landscape, they build broad floodplains, level expanses that are periodically inundated.

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Mass wasting includes slides and

slumps• Landslides are sudden

collapses of hillsides. In the United States alone, landslides and related mass wasting cause over $1 billion in property damage every year.

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Erosion destroys fieldsand undermines buildings

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Groins have mixed results

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Practice Quiz1. How does tectonic plate movement create ocean basins,

midocean ridges, and volcanoes?2. What is the “ring of fire”?3. Describe the processes and components of the rock cycle (fig.

11.7).4. What is the difference between metals and nonmetal mineral

resources?5. What is a mineral and a rock? Why are pure metals not

minerals?6. Which countries are the single greatest producers of our major

metals? (See fig. 11.10.)7. Describe some of the mining, processing, and drilling methods

that can degrade water or air quality.

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Practice Quiz8. Compare the different mining methods of underground,

openpit, strip, and placer mining, as well as mountaintop removal.

9. What resources, aside from minerals themselves, can be saved by recycling?

10. Give an example of resource substitution.11. Describe the most deadly risks of volcanoes.12. What is mass wasting? Give three examples and explain why

they are a problem.13. Why is building on barrier islands risky?14. What is a floodplain? Why is building on floodplains

controversial?15. Describe the processes of chemical weathering and mechanical

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Practice Quiz16. The Mesozoic period begins and ends with the appearance

and disappearance of dinosaurs. What fossils mark the other geologic eras? (See fig. 11.6.)

17. Describe how seismic exploration works in finding oil and gas deposits. What are its costs and benefits?

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