Badain Jaran Desert
The Badain Jaran Desert is a desert in China which spans the provinces of Gansu, Ningxia and Inner Mongolia. It covers an area of. By size it is the third largest desert in China.
This desert is home to some of the tallest stationary dunes on Earth, with some reaching a height of more than, although most average at around. Its tallest dune is also measured, from base to peak, as the world's third tallest dune and highest stationary dune in the world.
The desert also features over 100 spring-fed lakes that lie between the dunes, some of which are fresh water while others are extremely saline. These lakes give the desert its name which is Mongolian for "mysterious lakes". These lakes are not completely studied and high pH lakes harbor extremely interesting animal communities. It is also crossed by one river, the Ruo Shui, which has formed an alluvial plain in the desert.
Geography
Measuring over, the Badain Jaran Desert covers a significant part of the south-central part of the Inner Mongolia Autonomous Region as well as the North part of Gansu province. Located in the Alxa Plateau at about above sea level it is listed as a subsection to the Gobi Desert. It is bound to the north by the Gobi and to the East by Mount Lang which separates it from the Ulan Buh DesertAlthough most of the dunes in the desert are not stationary, the larger ones usually ranging above are static. With these dunes only the shallow surface of the sand is constantly shifting. The middle and lower layers of the highest dunes have been compacted for more than 20,000 years causing the sand particles to harden resulting in solid layers of sand and sandstone. High moisture levels inside the dunes also contribute to maintain their fixed state. This rigid structure also allows peaks, cliffs, gullies and even caves to form as a result of water erosion and desertification.
The Badain Jaran Desert, like the Tengger Desert which lies to the east is about one-half barren, sandy desert and one-half a mixture of solid bedrock and loose gravel. Several small lakes and oases scatter the desert around which limited vegetation is able to grow.
Lakes
The Badain Jaran Desert is well known for its numerous scattered and colorful lakes. Containing more than 140 lakes they are mainly found in the southern region in the desert. These lakes can easily be found in the larger valleys between large dunes, believed to provide the life sustenance in the desert supporting camels, goats and horses which are herded by nomads that travel through the desert. Most lakes also support a green ring of vegetation that populate the close vicinity around the lakes.Throughout the desert some lakes change color due to large populations of algae, Brine shrimp and mineral formations at different times in year. Evaporation can also allow others to turn into a hypersaline lake forming a salt crust around the rim of the lake.
Although their true sources are still debated it is believed that they are being maintained by underground water streams. Most arid deserts in China are surrounded by mountains that provide water sources, and this is the case with the Badain Jaran Desert. Runoff from the mountains is then collected through gravel deposits and this allows them to run through the desert, providing water sources for the scattered oases.
Within the desert there can be two main types of lakes found regarding their morphometry. The largely elongated shallow lakes mainly appear in the megadune area in the southeastern margin of the desert. Their depth often reaches less than and only measure about. The oval-shaped, deep lakes can also be found in the compound transverse megadune area. Their maximum depth reaches around and attain a maximum size of around. The lake water can be extremely saline. The shallow lakes in the southeastern region of the desert tend to have low salt concentration, averaging at less than. Other lakes can show higher salt concentrations going up to more than.
Singing Dunes
The Badain Jaran megadunes is one of the few places where the singing sand phenomenon occurs, in which the sand emits a sharp, loud noise that can be maintained for more than a minute. Although it is not fully understood, it is believed that it is caused by an electrostatic charge that is generated as wind pulls the top layers of sand down a dune slope. This will produce a low pitched rumble that can reach over 105 decibels. The "singing" starts with an avalanche of sand down the leeward face of a large dune. This phenomenon requires very specific circumstances to generate the sound. The dunes are silent throughout winter when humidity is retained in the sand. In the summer, when the sand is dry, the booming can be generated, but only on a slope of at least 30 degrees or more, on the leeward face of a dune; the same sand on the shallow, windward side cannot generate any noise. This phenomenon is only shared by around 35 other beaches and deserts around the world.Under the same circumstances, it is also possible to generate another acoustic phenomenon. Moving a hand gently through the dry sand of a "booming sand dune" will shear the upper layer of sand off the slope and generate a burping sound emission.
Dunes
The Badain Jaran Desert is made up of hundreds of dunes ranging from small to large. Most of the megadunes in the desert average about from the base while the rest average around. Out of all the megadunes, the Bilutu Peak is the most famous. It towers at from the base and is the tallest dune in Asia,. Unlike most of the smaller dunes the Bilutu Peak is stationary which makes it the world's tallest stationary dune.While the larger megadunes are stationary, the smaller dunes are constantly shifting according to wind patterns. This makes desertification a problem in surrounding areas as the desert is constantly expanding.
Climate
The average annual rainfall is only between and is mainly centered between June and August; however, the evaporation of precipitation is between 40 and 80 times than that of rainfall. Winter and spring have very strong winds coming mainly from the northwest getting to more than 60 days long. These winds can get up to wind force 8.| Description | Average Temperature |
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