Introduction
Barchan is a type of sand dune that is crescent-shaped and has horns pointing downwind. These dunes are commonly found in deserts and are formed by wind-blown sand moving in a specific direction.
Formation
Barchan dunes are formed when there is a steady supply of sand, strong winds, and a limited supply of vegetation to hold the sand in place. As the wind blows, it carries sand particles with it, depositing them on the stoss side of the dune (the side facing the wind). Over time, the sand accumulates and the dune begins to take on its crescent shape.
Characteristics
- Crescent-shaped
- Horns pointing downwind
- Steep, slip face
- Relatively small compared to other types of dunes
Examples
The Great Sand Sea in Egypt is known for its large barchan dunes, some of which can reach heights of over 100 feet. The Sahara Desert is also home to many barchan dunes, with some stretching for miles across the landscape.
Case Studies
A study conducted in the Namib Desert found that barchan dunes were migrating at a rate of up to 20 meters per year. This movement can have significant impacts on the surrounding ecosystem, displacing plants and animals in their path.
Statistics
Research has shown that barchan dunes make up approximately 10% of all dunes worldwide. They are most commonly found in regions with a dry climate and strong, consistent winds.
