The one landform most people imagine when they hear the word desert is the sand dune. Although they cover only 20 to 30 percent of the world’s deserts, these are the landscapes that provide the iconic images, robed and turbaned men riding camels in caravans across vast stretches of golden sands.
A dune is a mound of sand formed by the wind, usually along the beach or in a desert. Dunes form when wind blows sand into a sheltered area behind an obstacle. Dunes grow as grains of sand accumulate.
Dunes may be of many colors – bright as red in the Namib, red and orange in parts of Australia, or white as fresh snow in one basin in New Mexico. They also take different shapes, such as linear (narrow, long and wavy) as in the Simpson Desert of Australia, crescent-shape as in the Taklamakan Desert in western China, or star-shaped as in the Bardain-Jaran Desert that straddles Gansu province and Inner Mongolia in China. Follow the picture gallery below for a glimpse some of the most amazing sand dunes in the world.
Set within the coastal desert of Namibia are some of the biggest sand dunes in the world, with the highest reaching a height of 325m. The sand of Soosusvlei in the southern part of the world’s oldest desert derives its iconic red color from layers of iron oxide which coats it. The color of the sand, however, changes across the desert. Closer to the sea in the west, the sand appears whiter, whereas moving inland it turns reddish.
The Simpson Desert in Australia features more than 1,100 sand dunes that follow one another in parallel ridges. The desert stretches a mind-boggling 68,000 miles across Central Australia and looks as surreal as anything on Mars. There are more than 1,100 parallel sand dunes in this desert, each a wind-sculpted ridge of quartz grains coated in iron oxide, which rusts over time, producing awesome red and orange hues.
Sand dunes can take many shapes, depending on wind speed and direction, the availability of loose sand, and whether there is something on the ground that arrests the movement of sand grains. In contrast to the dunes of Australia’s Simpson Desert which are long, narrow, and slightly wavy, those in China’s Taklamakan Desert are crescent-shaped. These lie perpendicular to the prevailing winds and they form where the wind blows mainly from one direction all year round. Also known as Barchan dunes (a name with Turkic origins), the dunes of the Taklamakan migrate across the landscape, sometimes by more than a thousand meters a year.
In the local Uyghur language, the Taklamakan Desert roughly translates to: “You go in, but you won’t come out.” , a suitable name for a forbidding place where annually, less than 10mm of rain falls. This is China’s largest, hottest, and driest desert. It is huge (about the same size as Germany), and roughly 85 percent of the this fearsome desert consists of shifting sand dunes, some of which soar up to 200 to 300 meters (650 to 900 feet) in height. The world’s second largest moving-sand desert is also prone to massive dust storms (which I have personally witnessed while on the desert’s fringe in May of 2018).
The Badain Jaran Desert (Inner Mongolia, China)
The third largest desert in China is the Badain Jaran, which boasts one with the world’s tallest sand dunes. The Badain Jaran Desert spans the provinces of Gansu, Ningxia and Inner Mongolia and covers an area of 49,000 square km, making it the third largest desert in China after the Taklamakan and Gobi. Here, sand dunes here grow up to 500m, the world’s highest. Their star-shape formation is the result of multidirectional strong winds blowing across vast amounts of sand which carry the dunes upwards and outwards, radiating from a center point like a star. Outside of China, star dunes are found in such places as the Grand Erg Oriental of the Sahara Desert and the Gran de Altar in Mexico.
The glistening white sand dunes of New Mexico, southwestern United States, are an astonishing contrast to the sand and red colors we usually associate with deserts. Rising from the heart of the Tularosa Basin, White Sands National Park is 275 square miles of great wave-like dunes of gypsum sand, and the world’s largest gypsum dune field. The pure gypsum that forms these unusual dunes originates in the western portion of the monument from an ephemeral lake with a very high mineral content. As the water evaporates, the minerals are left behind to form gypsum deposits that eventually are wind-transported to form these white sand dunes. Many species of plants and animals have developed specialized means of surviving in this area of cold winters, hot summers, very little surface water and highly mineralized ground water.