EAS-100-51: Introduction to Earth Science

Note: These essay-style questions are a supplement to (NOT a subtitute for) lecture notes, handouts, and text reading
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1. If rocks are a record or "book" of the Earth's history, are all of the "pages" available for study? Why not? What earth processes prevented this?

2. ? rocks are formed from the cooling and crystallization of molten rock called ?. The size of the crystals are governed by the rate of cooling; hence, an igneous rock at or near the earth's surface cools more quickly, and the size of crystals is ? . Rocks which cool deep below the ground cool more ? and thus have a ? crystal size.

3. ? rocks are formed at the Earth's surface. Weathering and erosion produce fragments of broken rock, creating a subclass of sedimentary rocks known as ? , of which shales are most common. The most common chemical sedimentary rocks are which are usually made up of the accumulated shells of dead sea animals.

4. Why are clastic sedimentary rocks more common than non-clastics? Why are clay-rich clastic rocks most common?

5. ? rocks are changed by heat and pressure (usually a combination of both).

6. What are the basic components of a soil? How long does it usually take for nature to make a soil? In general, what components make a "rich" soil?

7. Why are soils in tropical climates (despite the abundance of vegetation) considered very poor for agriculture? How does nature compensate for the poor soil?

8. Where did the Earth's water originally come from? What processes brought it to the Earth's surface?

9. What percentage of the Earth's surface is covered by water? Why is most of this water not considered a readily usable resource?

10. Why do geologically-young streams form relatively straight stream courses and V-shaped stream valleys? Why do mature and old-age streams meander and have wide floodplains?

11. Why do sediments (which later become sedimentary rocks) tend to form layers? Why do rivers form deltas when they meet the ocean? Why are lake sediments usually fine-grained?

12. How does porosity differ from permeability? When applied to rocks, how do these terms define an aquifer, aquitard and aquiclude?

13. Name several types of rocks which would make good aquifers. Name several rocks which would not make good aquifers.

14. What geological conditions could create an artesian well? What is a perched water table?

15. What are the consequences of discharging water faster from an aquifer than it can recharge?

16. What major sedimentary formation underlying Chicago's bedrock is thousands of feet thick? How far does it extend laterally? Where does it outcrop at the surface? What is this outcrop called?

17. What eras of geologic time are missing in the Chicago area? Why are they missing? Approximately what amount of geologic time does this missing record represent?

18. What was Lake Chicago? How much did the lake levels change during the glacial stages of Chicago's history?

19. Why is the landscape of Chicago so unusually flat?

20. Name one cause for cooling of the earth's climate, which might cause an ice age. Name one cause for warming of the earth's climate, which might cause global warming (and melting of existing glaciers).

21. What was the original source of all the ice in the glaciers?

22. At what depth inside the ice sheets does the great overlying weight of ice cause the ice to behave plastically, making it flow downslope?

23. What the immediate consequences of a long-term world-wide warming trend in climate?

24. What are the consequences of a long-term cooling of the world's climate?

25. What are the economic uses of glacial deposits?

26. What generates the Earth's winds?

27. How are stalactites differentiated from stalagmites?

28. What percentage of the Earth's surface is now covered by arid and semi-arid regions.

29. Why is wind erosion relatively more important in arid regions than in humid areas?

30. How do sand dunes migrate?

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