Causes of formation of Yadan landform

Yadan landform is a unique landform formed in arid areas, and the reasons for its formation 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 produces cracks and holes on the rock surface. These cracks and holes can further accelerate the weathering process of rock materials, thus forming Yadan landform with special shape.

2. Wind erosion: In arid areas, there are often strong winds, which will carry particles such as sand and gravel and scrape and erode the rock surface. With the passage of time, these wind erosion will have a unique "carving" effect on the rock surface, forming a unique form of Yadan landform.

3. water erosion: in arid areas, although there is less precipitation, there may be short but severe precipitation during rainy season or snow melting, which will flow over the rock surface and form erosion or dissolution on the rock surface, thus forming a unique landform.

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

the origin of yadan's naming

the development of yadan's definition had many appellations before the word "yadan" was widely used by geologists. It is called Longcheng, Bailongdui and Longdui in Volume 28 of Geography of Hanshu written by Ban Gu, a historian of the Eastern Han Dynasty, and Stapff calls it "aerodynam ic landforms".

There are also "sphinx hills" and "bugra vyduvanije；; Deflation hill) ","Desert City (Shahrlut; Desert cities), "mud li-ons", "Tufu" and other different names.

From p>1899 to 193, when Swedish explorer Sven Heding visited Lop Nur, Xinjiang, China, he distributed around the ancient lake in groups, with a length of several hundred meters and a height of more than 2-3 meters, heading northeast-southwest, and the landform with different shapes was formed by water erosion and then wind erosion. According to the local Uyghur language, it was 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 "Yadan" in China. Since then, the word "Yardang" has been officially accepted by the scientific field. Following the discovery of Yadan landform in Luobu wasteland, many similar landforms have been found in many parts of the arid areas of the world, all of which are collectively called Yadan landform.

In p>29, on the occasion of the 6th anniversary of the founding of New China, the centenary of the founding of the Chinese Geographical Society and the centenary of the founding and development of modern geography in China, chinese national geography magazine and the Chinese Geographical Society jointly launched the "Centennial Discovery of Chinese Geography" selection activity. Among them, at the beginning of the 2th century, Chinese and foreign scholars discovered and named Yadan landform.