The Genesis of Ya Dan Landform

Ya Dan landform is a unique landform formed in arid areas, and its reasons mainly include the following aspects:

1. Weathering of rock materials: In arid environment, rocks are easily affected by natural forces such as sun exposure, wind blowing and drying, which gradually leads to cracks and holes on the rock surface. These cracks and holes can further accelerate the weathering process of rock materials, thus forming a special shape of Ya Dan landform.

2. Wind erosion: In arid areas, strong winds often appear, which will carry dust, gravel and other particles to scrape and erode the rock surface. With the passage of time, these wind erosion will produce a unique "carving" effect on the rock surface, forming a unique Ya Dan landform.

3. Water erosion: In arid areas, although there is little precipitation, there may be short but intense precipitation in rainy season or snowmelt period, which will flow over the rock surface and form erosion or dissolution on the rock surface, thus forming a unique landform.

The interaction of the above three factors, * * * together contributed to the formation of Ya Dan landform. It is worth noting that Ya Dan landform is a relatively stable landform type. Once formed, it can be preserved for a long time.

The origin of Ya Dan's naming

Before the word "Ya Dan" was widely used in earth science, Ya Dan's definition had many names. Ban Gu, a historian of the Eastern Han Dynasty, called it Longcheng, Bailongdui and Longdui in the 28th volume of Han Geography, and stapp called it "aerodynamic landform".

In addition, there are "The Sphinx Mountain" and "bugra vyduvanije；; Deflation Mountain), Desert City (Shahrlut Desert City), Niliong and Tufu.

1899 to 1903, when the Swedish explorer Sven Hedin visited Lop Nur, Xinjiang, China, he was divided into groups and distributed around the ancient lake, which was several hundred meters long and 2-3 meters high, heading northeast-southwest, and formed various landforms by water erosion and wind erosion. According to the local Uyghur language, it is called Yardang (originally meaning "hill with steep walls").

Later, with the wide spread of his book Central Asia and Tibet in academic circles at home and abroad, it was transliterated as "Ya Dan" in China. Since then, the word "Yadang" has been officially accepted by the scientific community. Following the discovery of Ya Dan landform in Rob wasteland, many similar landforms have been found in many places in arid areas of the world, which are collectively called Ya Dan landforms.

In 2009, on the occasion of the 60th anniversary of the founding of New China, the centenary of the founding of China Geographical Society and the centenary of the founding and development of modern geography in China, China National Geographic Magazine and China Geographical Society jointly launched the "Centennial Discovery of China Geography" selection activity. Among them, at the beginning of 20th century, Chinese and foreign scholars discovered and named Ya Dan landform.