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What are
deserts?
Basically, a
desert is a landscape form or region that receives
little precipitation (rain or snow) generally less
than 250 mm per year. The exact definition of a
desert is sometimes disputed and so various types
of arid zones have been defined.
Deserts often
have common features. Soil from deserts is mostly
composed of rocky surfaces called regs. Only a
minority of desert surfaces have sand dunes called
ergs and stony or hamada surfaces.
Rocky, exposures
of terrain are is the more typical. This shows poor
soil development and sparseness of vegetation. Some
parts of deserts may be salt-covered flats. A major
factor in shaping deserts is the wind (Eolian).
This can be seen in sand dunes but also windblown
rocks.
The dry
conditions of deserts, can be good places for human
artifacts and fossils to be preserved.
sources: Geoscience
Australia - Deserts
USGS
Deserts
Wikipedia-
Deserts
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A
classic image of the dunes of the
Sahara Desert, Algeria, 1984
Image: S.M Conan-Davies
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