Longitudinal Dune Landscape
Reference work entry
A longitudinal dune is an elongated sand ridge with an axis parallel to the dominant winds. It is a type of composite dune that is much larger than typical sand dunes. Sand ridges are normally flat or undulating in a wavy pattern. The surface of a sand ridge is stacked with many crescent-shaped sand dunes and dune chains. The longitudinal dunes of Mingshashan (Mingsha Mountain) in Dunhuang, Gansu Province, are 130 m high. The sand ridges in the Qaidam Basin, Qinghai Province, are 10–20 m high, the tallest can reach 40 m, and they are several hundred to several thousand metres long. Longitudinal dunes form due to the interaction of wind forces, which push a wing of a barchan dune forward, or by the transformation of sand dunes with vegetation cover. The entrance to the Taklimakan central composite longitudinal dune area, which contains groups of longitudinal dunes, is located 130 km south of the Southern Xinjiang Desert Highway in Xinjiang Province (Fig. 44).
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