CEEES/SC 10111-20111
Planet Earth
Laboratory 11: Deserts
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Warm arid and semi-arid regions have <25 and <50 cm rain per year, respectively.
They are characterized by sparse vegetation, little water, thin soils, frequent strong winds and sharp, angular landforms.
Mechanical weathering predominates; sedimentary particles tend to be coarser than in humid regions.
Although running water is the principal agent of erosion it is commonly present only after infrequent cloudbursts.
Flash floods remove the products of mechanical weathering and mass wasting and leave behind steep banks and cliffs.
These floods cause extensive erosion and sediment is quickly transported downstream.
When sediment-choked streams spill out into a valley, they spread out to form numerous interwoven shallow channels or
braided streams
.
Where strong winds blow and sand is available, dunes of several types may form.
Wind is primarily a transport and depositional agent – only minor erosional capabilities (
sand-blasting
).
Erosional Landforms
Depositional Landforms
Water Deposits
Wind Deposits
