Geomorphology of the megadunes in the Badain Jaran Desert

The Badain Jaran Desert features the highest megadunes on Earth, and a unique megadune-lake alternation landscape. Based on field survey and interpretation of aerial photographs, this paper examines the general characteristics of the Badain Jaran megadunes, their morphometry and formation, as well as the formation of megadune-lake alternation landscape. It is suggested that the megadunes in the Badain Jaran Desert were developed in a low wind energy environment. The compound transverse megadunes, the dominant megadune type, have a similar wind regime to barchanoid dunes, and the compound star megadunes, which occur near the mountains, have a similar wind regime to star dunes. Similar to the barchanoid dunes, the height, base area and spacing of the compound transverse megadunes show reasonably good inter-correlation. The base area of the megadunes and the area of the leeward interdune lake basins are also inter-correlated. The alignment and spacing of the Badain Jaran megadunes implies that wind is the most important factor in their development; the morphology underneath the megadunes does not determine the general pattern of the megadunes as previously suggested. Repetitions of dune fixation and reactivation in the development process played an important role in increasing the megadunesʹ height, hence their size. The interdune lakes in the megadune area were mainly formed by talus springs and are only partly fed by atmospheric precipitation.