Laboratory Manual for Introductory Geology 4e

16.2 Processes in Arid Regions
Now let’s examine why the scarcity of water in arid regions causes them to have landscapes
so different from those in humid regions. Features tend to survive longer in
arid areas than in humid ones because weathering, erosion, and deposition are slowed
by the scarcity of water, which is needed to abrade, dissolve, and carry debris away. In
the absence of water, soluble rocks such as limestone, dolostone, and marble—easily
weathered and eroded in humid regions to form valleys—become ridge formers.
Both physical and chemical weathering occur in arid regions. The dominant processes
of physical weathering are usually different from those in humid areas; for
example, where do you think root wedging is more common? In areas where rain is
rare, the major source of water for chemical weathering may be the thin film of dew
formed on rocks each morning. The scarcity of water limits chemical weathering
severely, and soil formation is slow. Exercise 16.2 explores some of these differences.
EXERCISE 16.2
Comparing Processes in Arid and Humid Regions
Name:
Course:
Section:
Date:
(a) In a few short sentences, describe how the processes in the table below are different in arid regions and humid
regions. Consider the nature and intensity of the processes and the role that water plays in each.
(b) What are the dominant processes in each of the two different environments?
Processes Arid regions Humid regions
Physical weathering
Chemical weathering
Mass wasting
Soil formation
Stream erosion
Wind erosion
Groundwater activity
16.2 PROCESSES IN ARID REGIONS
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