Deserts and Wind Action

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Reading Assignment

Chernicoff, Chapter 16, "Deserts and Wind Action."

Reminders

Do the reading! Expect to spend at least an hour preparing for every class by reading the assigned texts--not counting review time and homework time.

Clarification: Attendance at one of the weekly Friday night Planetarium presentations of the Mars Show will count as one journal. Complete the Mars focus and discussion questions worksheet and turn it in the week after viewing the show. Write the date you attended the Mars Show on your worksheet, and staple the worksheet to your ticket.

Reading Focus Questions

Read the entire chapter. Focus your attention on the following questions. Be prepared to answer any of these questions should they occur on a quiz. For multiple choice questions select the single best answer.

 

  1. Deserts receive less than _______ inches of precipitation annually.
    1. A(n) ____________ _______________ is a ratio of a region's potential annual evaporation to its recorded average annual precipitation.
    2. If this value is greater than ________ for an area, then that area is a desert.

     

  2. True or False? Deserts can occur in either cold or hot regions.

     

  3. True or False? Deserts are largely deserted of life.

     

  4. True or False? A dense forest might be a desert.

     

  5. Most deserts occur between ___ degrees and ___ degrees north and south of the equator.

     

  6. True or False? Water is the primary sculptor of desert landforms.

     

  7. A channel that carries a stream during a period of high discharge but is dry most of the year is a(n) _______________.

     

  8. A dry lake that develops when a desert floor lake evaporates is a(n) ______________.

     

  9. The removal of large quantities of loose material by wind is called _____________.

     

  10. Ventifacts are:
    1. layers of closely packed stones
    2. pit-like depressions in sand caused by wind
    3. stones shaped by wind abrasion
    4. large desert stones the size of icebergs

     

  11. What caused the Dust Bowl of the 1930's?

     

  12. Most dunes slope by _______ degrees on the windward side and by _______ degrees on the leeward (downwind) side.

     

  13. The steepest side of a dune is the ____________ _____________.

     

  14. True or false? It requires more wind to create a large dune; therefore, large dunes migrate faster than small dunes.

     

  15. The horns of Barchan dunes point... | upwind | downwind (circle one).

     

  16. Answer question 3 in "For Further Thought" on p. 341.

     

  17. Winds of the past are called ____________________.
    1. Examine the cross-bedding evident in Figure 16-26 on p. 337.
    2. What clues would indicate that a sandstone formation was deposited by wind instead of under water?

     

  18. _______________ is the invasion of desert conditions into formerly nondesert areas.
    1. What has caused this process to occur in the Sahel?
    2. What might prevent it?

     

  19. True or False? Because Mars' atmosphere is so thin, very little dust actually blows.

 

Class Agenda