What are longitudinal dunes?
[ lŏn′jĭ-tōōd′n-əl ] A large, elongated dune lying parallel to the prevailing wind direction. Longitudinal dunes usually have symmetrical cross sections. They generally form in areas that are located behind an obstacle where sand is abundant and the wind is constant and strong.
What are transverse dunes?
[ trăns-vûrs′, trăns′vûrs′ ] A large, strongly asymmetrical, elongated dune lying at right angles to the prevailing wind direction. Transverse dunes have a gently sloping windward side and a steeply sloping leeward side. They generally form in areas of sparse vegetation and abundant sand.
How are parabolic dunes formed?
Parabolic Dunes If strong winds erode a section of the vegetated sand (commonly referred to as a blowout), a parabolic dune may form. Leeward motion occurs if sand from the blowout is deposited on the opposite slope of the parabolic dune.
Where are transverse dunes found?
Distribution. Transverse dunes are less common than linear dune forms. On Earth, barchans can be found in sediment-rich hyperarid areas, such as the Sahara Desert (Bagnold 1941).
What is a Crescentic dune?
Crescent dunes are sand dunes with two “horns” that point away from the wind. These dunes are also one of the most movable types of sand dune, blown by the wind along the desert at up to 50ft (15m) each year. Crescent dunes are also called barchan dunes.
What is Star Dune?
Radially symmetrical, star dunes are pyramidal sand mounds with slipfaces on three or more arms that radiate from the high center of the mound. They tend to accumulate in areas with multidirectional wind regimes. Star dunes grow upward rather than laterally.
How are Ventifacts formed?
ventifact, stone that has received one or more highly polished, flattened facets as a result of erosion by windblown sand. Ventifacts are produced under arid conditions and are generally formed from hard, fine-grained rocks such as obsidian, chert, or quartzite.
What is a razorback dune?
A “Razorback” is a dune hazard that is formed when the wind blows sand in multiple directions and a knife-edge ridge appears at the top. The size of a razorback can vary from gradual to very steep. Here are some tips on how to avoid hitting a Razorback and stay safe throughout your visit to the Dunes.
What bar Khan called?
barchan, also spelled Barkhan, crescent-shaped sand dune produced by the action of wind predominately from one direction. One of the commonest types of dunes, it occurs in sandy deserts all over the world. Fast Facts.
https://www.youtube.com/watch?v=TvJQ0GTeZgw