Card Set Information

2010-05-06 04:09:28
eolian geology dehon

Terms and question on wind systems
Show Answers:

  1. The major desert areas of the world all lie between __ and __ degrees north or south of the equator.
    10 and 30
  2. What are the two ways wind erosion ways in?
    deflation and abrasion
  3. Define deflation.
    the lifting and removal of loose sand and dust particles from Earth's surface
  4. Define abrasion.
    the sandblasting action of wind-blown sand
  5. Deflation commonly occurs in semiarid regions where the protective cover of grass and shrubs has been removed by the activity of humans and animals. The results are board shallow depressions called what?
    deflation basins
  6. Wind can move only move sand and dust-sized particles, so the deflation leaves concentrations of coarser material known as?
    lag deposits or desert pavements
  7. What two landforms do abrasion leave behind?
    ventifacts and yardangs
  8. Wind transports sand by ____ and ____.
    saltation and surface creep
  9. Dust storms form thanks to what type of cloud?
    cumulonimbus cloud
  10. Explain have a sand dune migrates.
    A sand dune migrates as sand grains move up the slope of the dune and accumulate in a protected area on the downwind face. The dune slowly moves grain by grain. As the grains accumulate on the downwind slope, they produce a series of layers (cross-beds) inclined in a downward direction.
  11. Name the five types of dunes.
    transverse, barchan, longitudinal, star, and parabolic dunes
  12. Which type of dune usually covers sand seas?
    transverse dunes
  13. Barchan dunes form where the supply of sand is _____ and winds of moderate velocity blow in _____ direction.
    limited; constant
  14. What type of dune forms with three or more wind directions?
    star dunes
  15. What type of dune are formed with a limited sand supply and two wind directions?
    Longitudinal dunes
  16. Parabolic dunes are formed by _____ winds.
    strong onshore
  17. Define Loess.
    Loess is a deposit of wind-blown silt.
  18. Rock flour comes from where?
    glacial outwash
  19. Desertification is what?
    where productive land is convert to desert