A typical romanticized desert scene involves camels
picking their way across immense expanses of sand dunes. This is
a rather simplistic view which ignores the wide variety of environments
and cultures found in the world's deserts.
Nevertheless, these vast expanses of sand do indeed exist, seas of sand
which have built up over thousands of years. Nearly all of the Earth's
moving sand is held in large areas of active sand dunes. They take
erg (plural areg) - Arabic for 'ocean'
koum - Turkic for 'sand'
nefud - Arabic, a smaller, elongate sand sea
sha-mo - Chinese for 'sand river'.
(not referring to sand: reg (Arabic) = gobi (Mongolian) = desert
pavement = gibber plain)
The generic landform term preferred by geographers is 'erg'. An arbitrary
cutoff size of 125 km2 has been adopted; areas smaller than
this are simply "dune fields".
Every erg in the world was formed from a specific source of sand, from
a specific event of desertification. For some of them, the sand collected
in low basins. Frequently, sand piles up against the hills or mountains
ringing such a basin, and spills out through the passes. Other
masses of sand are still moving, and are where they are simply because
that was how far the wind could push them in the time since they were formed.
Most ergs are still accumulating sand. A few have been stabilized
OK, I said to myself. 85% of all the Earth's mobile sand is found
in ergs that are larger than 32,000 km2 (a little bit bigger
than Belgium). How many of them can there be? This led me
on a frustrating search for the world's big ergs. Starting from an
unlabeled world map in an old geomorphology textbook, I hunted through
the Web for dune fields around the world. Most of my virtual
journey involved dozens of travel sites, too numerous to name here, from
which the name of a single erg was extracted. The list below
probably resembles a list of the world's deserts as much as a list of actual
The sizes of the ergs listed below are quite uncertain. Not only
do people frequently confuse the sand sea with the desert (none are all
sand), these things are growing because of climate changes around the Earth.
Namib Sand sea (34,000 km2)
Kalahari Desert (stable, into Namibia and South Africa) It's difficult
to find a good map of Botswana, let alone one that shows where the dunes
Pakistan and India
Kara Kum "Black Sand" (300,000 km2)
Many of the names here are tentative, as I had to transliterate Wade-Giles
spelling into Pinyin via a table.
Takla Makan, (Taklimakan Shamo) Xinjiang
Guerbantonggude Shamo, Xinjiang (Dzungaria)
Surprisingly, the Great Gobi has few sand dunes, except for its southern
extensions in north-central China.
Badain Jaran or Badanjilin Shamo, Gansu (Inner Mongolia?)
Tengger or Tenggeli Shamo, Gansu-Ningxia
Ordos (Mu Us Shamo)
Wulanbuhe Shamo, Ningxia
Maowusu Shamo, Inner Mongolia
Gubuqi Shamo, Inner Mongolia
An unidentified sandy area appears on the atlas in eastern Inner Mongolia,
about 200 km due north of Beijing. The atlas also shows large sand dune
areas around Tongliao in Jilin, but does not name them. These
could be loess dunes, however.
About one-sixth of Australia is covered with sand dunes. These are typically
thin, with the underlying rock appearing bewteen widely spaced dunes.
Embassy of Niger - Niger Profile (recovred from Google cache)
Geomorphology from Space: A Global Overview of Regional Landforms
Global Desert Monitoring with ASTER
Times Atlas of China, 1970
Chorley, Richard J, et. al. Geomorphology, p. 411.
Methuen and Co, New York/London, 1984.
La Ruta de Sonora Ecotourism map