Bài IELTS Task 1 - Process - Sand dune forming

Question

The diagram below shows the stages of sand dune forming

The given diagram illustrates how sand dunes are formed in deserts and on coast by wind power. Overall, the three main stages involved show that sand particles are drifted by wind from dry ground to wet ground where they gather and create sand dunes. In addition, the larger the area of wet ground is, the taller and bigger the sand dunes are formed.

In the first stage, sand grains from dry ground are blown by the wind along the surface until they meet with a wet area of sand, where they are stuck and build up separate piles. As the wind blows, more sand grains are carried towards the formed piles and some of these grains accumulate into a combined and taller pile.

The wind continues blowing and the pile of sand gets taller and bigger and turns into sand dunes. At the same time, sand articles that cannot be cohesive to that sand dune keep on moving until they are stuck by another wet area, where they mount up another dune. The process repeats all over again and many other sand dunes are created.