What is the meaning of "Ya Dan" in Ya Dan National Geographic Park?

"Ya Dan" comes from Uygur language, which means "a mountain with steep walls". Ya Dan landform is a landform formed by strong wind erosion, transportation and accumulation, which often presents wind erosion ridges, hills, wind erosion troughs, depressions and other forms. This landform appears in windy and dry ancient lake basins or lake plains and Gobi desert. Lop Nur and Wuerhe in Xinjiang, China are typical of this landform. Whenever the wind howls, it rolls up the dust all over the sky, and the sun and the moon are dull and the direction is unknown. The wind is like a ghost crying and wolf howling. This is a completely horrible world. After the gale stops, the images of wind erosion ridges, hills, wind erosion troughs and depressions are like castles and streets. And another gale will change everything. Therefore, the Ya Dan landform of Wuerhe is called "ghost town".

Ya Dan is the transliteration of Yadaner, which means steep sand dunes. Ya Dan landform is a wind erosion landform, also called sand erosion mound or wind erosion mound, which means "weathered mound group" in Uygur language. Geographically, it is the general name of wind erosion in arid areas. The arid desert, loose rock structure and local strong wind are the basic factors that form the landform of Ya Dan.

Ya Dan landform has hard soil and light red rocks. The grotesque and patchy azithromycin particles carved by desert wind have different shapes, which are in sharp contrast with the blue Gobi Desert and stand out against the blue sky and white clouds.

On the land of Lenghu 1.7 million square kilometers, the area of Yadanlin accounts for more than 94%. Ya Dan, Qaidam, is a lake sediment of Late Tertiary and Early Quaternary 75 million years ago, which was separated from the water body due to the uplift of geological movement. The salt sand crust in this period was carved by the west wind. They are widely distributed in the northwest of Qaidam, which is one of the largest and most typical Ya Dan landscapes in the world, especially Nanbaxian and Yiliping, with a distribution area of 1000 square kilometers. Because of its strange and grotesque landforms, erratic winds, mysterious and horrible winds generated by strange landforms, and the local rocks are rich in iron and strong in geomagnetism, the compass often fails, leading to disorientation and getting lost. It is regarded as a ghost town, maze and unique by the world. The total area of Yadanlin here is about 2 1 1,000 square kilometers, with an average elevation of 3,260 meters. It is the largest wind erosion soil forest group discovered in China so far.

The height of Yadanlin ranges from about four or five meters to twenty or thirty meters, and its length and width range from tens to hundreds of meters. On the whole, some are similar to the descriptions of ancient castles, temples, imperial tombs and hordes; Some are similar to "whales frolicking in the sand", "millions of sea lions facing the sun" and "Wanlong formation", which are very spectacular. From a close distance, they are also full of weather: some mounds are like warships full of sails and about to sail; Some are like big cocks corrected by males, stretching their necks to crow; Some are like pavilions in a small bridge, and some are like lovely animals such as horses, camels, elephants, lions, tigers, whales, dragons and birds. Everything is mysterious and wonderful.

In 1950s, eight southern female geologists came here to look for oil resources, and died because they got lost, so the place of "Southern Eight Immortals" came into being. Wind erosion landform is a natural wonder in Qinghai.

Geographical location:

Located in the south of Chaidamu Cold Lake in Haixi Prefecture, Baxian, Huangguagou, Aobaoliang, Niubiziliang, Kate Mirica, No.4-No.7 Structure of Cold Lake, Yiliping, Chalangkou and Ga Schooler Lake in the south of Dafeng Mountain.

Travel guide:

Precautions:

Director of photography:

Related information:

Ya Dan is a geographical term, which refers to various Xiangtu-like deposits in ancient rivers and lakes eroded by wind in arid areas. At the beginning of the 20th century, when western explorers visited Lop Nur, Xinjiang, they saw many boat-shaped mounds distributed around the ancient lake in groups, generally about 6 meters high. They were written as Yardang according to the names of local Uighurs, and the word yardang has been circulated in foreign academic circles since then.

China Ya Dan has a landform area of more than 20,000 square kilometers, mainly distributed in the northwest of Qaidam Basin in Qinghai, the middle and lower reaches of Shule River in Xinjiang and around Lop Nur. The landform of Ya Dan in Xinjiang is only 3000-4000 square kilometers, which is very small. A typical Ya Dan is 4-5 meters high and 10-20 meters high, which is also called a countertop, that is, a square table. Ya Dan Group, located in Tebes wasteland in Chad Basin, Africa, has the largest range, about 260,000 square kilometers. The highest and largest Ya Dan is located in the southeast of the Iranian Root Desert, covering an area of about 20,000 square kilometers. Ya Dan is 200 meters high and the wind erosion valley is 500 meters wide. Ya Dan stretches like a ridge, several kilometers to more than ten kilometers long. Ya Dan, an ancient sea in Dunhuang, is 20- 100 meters above sea level. It belongs to the medium and large Ya Dan Group, with narrow wind-eroded valley, rich and colorful Ya Dan shapes and rare high-density types in the world. It is close to Dunhuang, with convenient transportation and excellent location advantages. It is a treasure house of tourism and scientific research.

From Anxi county, 265 kilometers northeast to Jiayuguan city, the Gobi scenery along the way is unique. Among them, Bulongji Township, located 45 kilometers east of the county seat, is a typical landform wonder of Ya Dan, with various and jagged wind erosion beaches on both sides of the road. Ya Dan landform is named after the most typical wind erosion landform in Ya Dan near Lop Nur. Due to thousands of years of wind and sun exposure, the sandstone layer with flat surface has formed many landforms such as wind erosion walls, wind erosion mushrooms, wind erosion columns, wind erosion ridges and gullies, wind erosion depressions, residual hills and castles. The scenery is spectacular and amazing. Anxi County, known as the "World Wind Bank", is located in a long and narrow corridor between two mountains, with an altitude of only 1 170 meters and low terrain. When the air flows in, the thin tube plays a role in accelerating the airflow movement, so strong winds often form. Sandstorms have already endangered the lives of Anxi residents and 3000 mu of cultivated land. There are 6 desert strongholds in the county, covering an area of more than 300,000 mu. This windy weather often makes the landforms of Ya Dan change greatly and have different shapes.

Ya Dan landform refers to the fragmented ridge and gully landform formed by lake deposition or wind erosion of alluvial plain in arid areas. Ya Dan is called in Uyghur, which means a mountain with steep walls. The raised wind erosion hills are long, and the arrangement direction is parallel to the main wind direction. Recent research shows that the erosion of temporary running water and lake water is also one of the important reasons for the formation of Ya Dan. The landform of Ya Dan is most typical near Loulan in the northwest of Lop Nur. (Information provided by the Ministry of Land and Resources)

In the inland desert of China, there are a series of long mounds and grooves extending intermittently, which is the landform of Ya Dan. During the joint inspection in Lop Nur in the 20th century, junior high school and foreign scholars discovered this peculiar landform near Guloulan in the northwest of Lop Nur, and named it according to the Uighur appellation, and then translated it back into Chinese as "Ya Dan".

Ya Dan can be found in many arid areas in the world, not only in Xinjiang, China. The road from You Xiang in Qinghai to southern Xinjiang is very desolate. Ya Dan can be seen between Nanbaxian and Yiliping Highway, which is the largest distribution area of Ya Dan in the northwest inland. However, Ya Dan landform is the most widely distributed landform in Xinjiang. Besides Ya Dan and Guloulan in Lop Nur, the ghost town in Karamay and the windy city in Qitai are also typical Ya Dan landforms.

Formation mechanism of Ya Dan landform

There are two key factors in the formation of Ya Dan. First, the geological basis for the development of this landform, that is, lacustrine sedimentary strata; The second is external force erosion, that is, strong directional wind erosion and flowing water erosion in the desert.

Lakes in arid areas often include repeated water inflow and water withdrawal in their formation history, thus developing overlying mudstone layers and sandy soil layers. Wind and running water can take away loose sandy soil layer, but it has limited effect on hard mudstone layer and gypsum cementation layer. However, the dense mudstone layer is not indestructible, and the expansion and contraction effect caused by severe temperature difference in desert area will eventually lead to the disintegration of mudstone layer, and the exposed sandy soil layer will be carried away by wind and running water and evolved into a groove shape; The part still covered by mudstone is relatively stable, forming large or small strip mounds, and the landform of Ya Dan gradually appears.

The external factors that form Ya Dan are usually considered as the dominant factors of strong prevailing winds, but this is not a single dominant factor. For example, in the east of Acic Valley, the direction of Sanlongshayadan is southeast, perpendicular to the prevailing northwest wind direction and consistent with the flow direction of mountain torrents, indicating that floods play a leading role in this Ya Dan; In addition, some Ya Dan are formed by the interaction of wind and flowing water, such as Ya Dan in Longcheng.