Article
Article
Dune
Article By:
Loope, David B. Department of Geology, University of Nebraska Medical Center, Lincoln, Nebraska.
Last reviewed:November 2019
DOI:https://doi.org/10.1036/1097-8542.206600
Mobile accumulation of sand-sized material that occurs along shorelines and in deserts because of wind action. Dunes are typically located in areas where winds decelerate and undergo decreases in sand-carrying capacity. Dunefields are composed of rhythmically spaced mounds of sand that range from about 3 ft (1 m) to more than 650 ft (200 m) in height and may be spaced as much as 5000 ft (1.5 km) apart. Smaller accumulations of windblown sand, typically ranging in height from ¼ to ½ in. (5 to 15 mm) and in wavelength from 3 to 5 in. (7 to 12 cm), are known as wind ripples. Dunes and ripples are two distinctly different features. The lack of intermediate forms shows that ripples do not grow into dunes. Ripples commonly are superimposed upon dunes, typically covering the entire upwind (stoss) surface and much of the downwind (leeward) surface as well.
The content above is only an excerpt.
About AccessScience
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 10,000 highly qualified scientists and 46 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information
