A crescent-shaped sand dune, in which the horns point downwind in the direction of dune migration. Barchans are a type of transverse dune that tends to form where either sand transport rates are high and/or sand supply is limited; thus, they frequently occur on the margins of sand seas and migrate over nonsandy surfaces. Barchan dunes are not necessarily a very common type of dune, but the frequent simplicity of form has made them the source of investigations into aeolian sand transport on dune forms. (See dune.)
A large-scale accumulation of aeolian sand dunes geographically distinct from other sand fields but smaller than a sand sea.
A depression between barchans or barchanoid sand ridges, especially where dunes are pressing closely on one another. In Australia the term may be us
Crescent-shaped dunes, known as barchans, form where there is little sand on the edge of a desert and where the wind blows mostly in one...