Definition of "barchan"

The sand is usually very well sorted in barchans, for it is constantly re-worked as the dune ‘marches’. The marching also causes cross-bedding inside the barchan, with a dip parallel to the sand-fall face.

1966, Edwin Sherbon Hills, Arid Lands: A Geographical Appraisal‎, page 72

But to follow the dunes around the foot of their slopes is also tedious and one can walk for half a kilometre east or west, finding one barchan linked to another and no easy way through […] .

1988, Robert Irwin, The Mysteries of Algiers, Dedalus, published 1993, page 69

Barchans and transverse dunes are essentially of the same type, forming and migrating under a unidirectional wind regime. The difference between the two is related to the amount of sand: barchans are isolated mounds, whereas transverse dunes are composed of many barchans coalesced into a single, longer dune form (Tsoar 2001).

2008, Julie Laity, Deserts and Desert Environments‎, page 205

Perhaps the most distinctive is the barchan dune, an isolated crescentic form with arms that stretch downwind. Barchans are not huge, often with heights of only a few meters.

2010, Robert S. Anderson, Suzanne P. Anderson, Geomorphology: The Mechanics and Chemistry of Landscapes‎, page 482