Geology Reference
In-Depth Information
Chapter 14
Blowing in the Wind: Moving
Sediments without Water
In This Chapter
Describing regions where wind is important
Moving sediments with wind currents
Spotting features of wind erosion
Depositing sediments as dunes and loess
Debating the formation of desert pavement
Much of the earth's surface is subjected to change by forces of water (see Chapters 12,
13, and 15). But in regions that lack water, such as deserts, wind is the most important
geologic force; it creates geologic features by removing rock particles
(erosion)
and
adding new sediments
(deposition).
The term
aeolian
(sometimes spelled
eolian
) de-
scribes the processes and features of wind.
In this chapter, I explain how wind shapes the earth's surface and describe geologic fea-
tures associated with the processes of wind erosion and deposition.
Lacking Water: Arid Regions of the Earth
Wind creates prominent geologic features in areas of the earth that do not have much wa-
ter. These relatively dry or
arid
regions occur anywhere on the planet that the amount of
precipitation
(rain and snowfall) is less than the amount of water lost to
evaporation
(the
transformation of liquid water into water vapor by heat). When the sediments are dry,
they become susceptible to transport by wind.
Unlike what you may see in movies and television, the arid regions of earth are not all
hot, sunny, sand-covered expanses. On the contrary, only a few arid regions meet that de-
scription, such as the Arabian Desert of Saudi Arabia. Other arid landscapes occur in cold
