Sand Dunes of the Southwest

Sand Dune Glossary

Aeolian - (British spelling) Formed or deposited by the action of wind.

Aeolus - The wind god in Greek mythology.

Angle of Repose - A measurement of the steepest angle of a slope (determined by friction, cohesion, and the shapes of the particles) at which loose granular material such as sand will remain in place rather than falling or sliding. (A low angle of repose = flatter slopes and a high angle of repose = steeper slopes.)

Avalanche - A large amount of sand sliding down the slip face, which occurs when the buildup of sand at the leading edge of the dune exceeds the angle of repose.

Concave - curved inward.

Convex - curved outward.

Coppice - A vegetated sand mound, formed by sand accumulating around the lower parts of bushes.

Crest - The highest point; summit.

Dune - A large hill of windblown sand, usually with a distinct slip-face; found in deserts or near lakes and oceans.

Dune Field - An area covered by extensive sand dunes. According to the U.S. Geological Survey, “The size, character, and extent of dune fields depend on many variables that determine the supply and mobility of eolian sediments. Factors include source materials, wind direction and magnitude, precipitation patterns, and landscape (geospatial) configurations relating to sediment supply, migration paths, and depositional setting.”

Eolian - (American spelling) Formed or deposited by the action of wind.

Eolian Geology - The study of landforms created by wind.

Erg - Sand sea; a vast dune field deeply covered with sand and topped with many dunes (the term erg in Arabic means a vein or belt).

Interdune - A flat area between dunes; may closed and basinlike or open and continuous, and may or may not contain vegetation.

Lee(ward) - The side facing away from the wind.

Playa - A dry lake bed that forms in desert basins, where rivers merge but do not drain, that contains seasonal, shallow lakes which evaporate quickly, sometimes leaving behind deposits of salt or serving as a source of sand.

Ridge - A long, narrow, elevated crest that continues for some distance. Many dunes are known for their sharp, knife-edge ridges.

Saltation - The jumping or bouncing movement of sand caused by the wind.

Sand Bridge - A small chain of sand linking two large parallel dune formations.

Sand Ramp - A sloped build-up of sand on the flank of a mountain that may contain a combination of eolian and alluvial deposits.

Sand Ripples - Small, low, wave-like formations of sand made by the action of wind on the sand surface.

Sand Shadow - A small lee-side mound of sand that accumulates in the shelter of some obstacle.

Sand Sheet - A relatively flat plain of sand, often found around dune fields or transitional between the source area and the dunes.

Shadow Zone - In dunes, an area where the sand cannot be picked up and moved by the wind, so it remains in place.

Slack - A valley or trough between dunes.

Slip Face - The steeply sloped leeward side of a dune that faces away from the wind.

Stoss - The windward side of a sand dune.

Surface Creep - The rolling and pushing of sand and slightly larger particles by the wind.

Windward - The side facing into the wind.

Website design and content (c)2010 by Peter Olsen. This educational unit study was my PVCC honors project for GPH 211 Landform Processes.