The composition of Danniang sand dunes mainly comes from
The materials that formed the Danniang sand dune were mainly transported by water and wind.
The reason for the formation of Danniang sand dunes
Danniang's sand dunes were formed by the accumulation of wind power. Every winter and spring, the climate in this area was dry, and the wind was strong. In addition, the vegetation was thin, and the wind was less blocked when it passed through the river. It formed a vortex updraft, which carried the sand on the sandbar and the floodplain. It was blocked by the terrain along the river, and the wind speed slowed down. The sand piled up on the hillside, forming Danniang sand dunes over time.
The reason for the change in the area of Danniang sand dunes
The reason for the change in the area of Danniang sand dunes was that excessive cutting, logging, and grazing led to soil erosion in the area, and sand flowed into the valley. Every winter and spring, the water level of the river was relatively low, and the river banks and sandbars were exposed. The strong wind carried the sand on the sandbars and river banks, which was blocked by the mountainous terrain beside the river. The wind speed slowed down, and the sand piled up on the hillside, forming sand dunes over time. In summer, the water level of the river was high and the flow speed was fast. It had an erosive effect on the Danniang sand dunes, causing the sand dunes to shrink.
How were the Danniang sand dunes formed?
Danniang sand dunes were formed by the accumulation of wind power. Every winter and spring, the climate in this area was dry, and the wind was strong. In addition, the vegetation was thin, so the wind was less blocked by the river surface, forming a vortex updraft. These air currents carried sand grains from the sandbars and floodplains, which were blocked by the mountainous terrain by the river. The wind speed slowed down, and the sand grains piled up on the hillside, forming Danniang sand dunes over time.
The reason why Danniang's sand dunes grow taller
The reason why Dan Niang's sand dunes grew taller was due to the accumulation of wind power. Every winter and spring, the area where Danniang Dune was located was relatively dry and windy. When the wind passed through areas with little vegetation, it would carry sand from sandbars and floodplains. As there were fewer obstacles, when the wind slowed down, the sand would pile up on the hillside and gradually form the Danniang sand dune. The sand mainly came from the nearby sandbars and floodplains. The sand grains of the Danniang sand dune were very fine, showing beautiful curves and wave-like patterns.
Danniang sand dunes formed, the reason for the dominant wind direction
Danniang's sand dunes were formed by the accumulation of wind power. Every winter and spring (mainly from October to March of the next year), the climate in this area was dry, and the wind was strong. In addition, the vegetation was thin, and the wind was less blocked by the river surface, thus forming a vortex updraft. The airflow carried sand grains on the sandbars and floodplains. It was blocked by the mountainous terrain along the river, and the wind speed slowed down. The sand grains piled up on the hillside and accumulated over time to form sand dunes. Regarding the dominant wind direction of Danniang Dune, according to the information provided, documents 1 and 2 described that Danniang Dune was located at the foothills on the north bank of the Yarlung Zangbo River in Milin County, Xizang, while documents 2 and 3 mentioned that there was little rainfall in winter and spring, the river level was low, and the beach and sandbar were exposed. However, there was no clear information about the direction of the wind. Thus, it was impossible to determine the dominant wind direction of Danniang's sand dune.
What are moving sand dunes and fixed sand dunes
Moving sand dunes referred to sand dunes that were easily changed in position. There was little vegetation on the surface, and the sand dunes had a typical shape. They were easy to move along the wind under the influence of the wind. It poses a great threat to transportation and industrial and agricultural construction. The moving speed of a moving sand dune is related to the height of the sand dune, the wind speed and its variation rate, and the condition of the underlying surface. It was mainly distributed in China's Xinjiang, the Yellow Plateau, and the Inner Mongolia Plateau. A fixed sand dune was a sand dune that had a relatively constant position. Most of the ground was covered by vegetation, covering more than 30%, causing the movement of sand to almost completely stop, and the position of the sand dune was relatively stable. The formation of fixed sand dunes was closely related to vegetation. The blocking effect of vegetation began to accumulate, and as the accumulation thickened, it grew taller, forming a multi-layered arc bedding structure. The fixed sand dunes had little effect on the sand movement. According to the information provided, moving sand dunes and fixed sand dunes could be distinguished according to the following characteristics: - Vegetation coverage: There is little vegetation on the surface of moving sand dunes, while most of the fixed sand dunes are covered by vegetation. - Sand dune mobility: Moving sand dunes are easy to move with the wind, while fixed sand dunes are relatively stable and almost do not move. - Sand dune shape: The moving sand dunes are typical, often in the shape of a crescent, while the fixed sand dunes are in the shape of multi-layered arc bedding structure. In summary, there were obvious differences between moving sand dunes and fixed sand dunes in terms of vegetation coverage, sand dune mobility, and sand dune shape.
Where does the sand source of Danniang Sand Dune come from?
The sand source of Danniang Sand Dune mainly came from the nearby sandbars and floodplains.
Danniang Sand Dune's Sand Source
The sand source of Danniang Sand Dune mainly came from the exposed river course of the Yarlung Zangbo River during the dry season. Sand grains accumulated on the hillside over time to form sand dunes.
The Cause of Danniang Sand Dune
Danniang's sand dunes were formed by the accumulation of wind power. Every winter and spring, the climate in this area was dry, and the wind was strong. In addition, the vegetation was thin, so the wind was less blocked by the river surface, forming a vortex updraft. These air currents carried sand grains from the sandbars and floodplains, which were blocked by the mountainous terrain by the river. The wind speed slowed down, and the sand grains piled up on the hillside, forming Danniang sand dunes over time. The formation of sand dunes took decades or even centuries. It was the result of the interaction between the natural environment and the wind.
Danniang Sand Dune Encyclopedia
Danniang Sand Dune was located in Danniang Township, Milin County, Xizang, 90 kilometers away from the confluence of the two rivers. It was the largest sand dune in the middle of the Yarlung Zangbo River. The sand dunes were formed mainly because the sand grains from the nearby sandbars and floodplains were piled up on the slopes by the wind, forming the current sand dunes over time. Danniang Sand Dune was also known as the Buddha Palm Sand Dune because it was shaped like a Buddha's palm. The climate in this area is diverse, including tropical, sub-tropical, temperate-zone and frigid climate, and the annual rainfall is about 650 millimeters. The best season to view Danniang sand dunes was winter and spring. At this time, the water flow of the Yarlung Zangbo River slowed down, the riverbed was exposed, and the wind was strong, making the sand dunes more obvious.