- Erg's are broad, flat area of desert covered with wind-swept sand with little or no vegetative cover.
- The term takes its name from the Arabic word, meaning "dune field".
- An erg is defined as a desert area that contains more than 125 square kilo metres of aeolian or wind-blown sand and where sand covers more than 20% of the surface.
- Smaller areas are known as "dune fields". The largest hot desert in the world, the Sahara, covers 9 million square kilometres (3.5×106 sq mi) and contains several ergs.
- Sand seas and dune fields generally occur in regions downwind of copious sources of dry, loose sand, such as;
-glacial outwash plains
- All major ergs are located downwind from river beds.
- Individual dunes in ergs typically have widths, lengths, or both dimensions greater than 500 m.
- The depth ergs is selima Sand Sheet of Southern Egypt,Simpson Desert in the Sahara
- Mesozoic and Paleozoic ergs reached a mean depth of more than 100m..
- The only active erg in North America is in the Gran Desierto de Altar
- The largest are in northernand southern Africa, central and western Asia, and Central Australia.
- In South America, ergs are limited by the Andes Mountains.
some examples-: -Coastal Peru
- Northwestern Argentina
-Northeast coast of Brazil.
|Issaouane Erg Algeria|