Chandana Chandra explains: Hot deserts are barren landmasses covered with sand, having few water bodies. They cover about one fifth of the Earth’s land surface. The arid climate makes vegetation sparse in the desert.

The desert soils are course-textured, shallow, rocky or gravely with good drainage and have no sub-surface water. They are coarse because there is less chemical weathering. At times these deserts may be covered with huge boulders. This generally happens when the finer dust and sand particles are blown away, leaving behind heavier pieces of rock.

“Due to high temperature and lack of rainfall, sufficient transpiration through evaporation can’t take place. Thus big trees which can prevent soil erosion do not grow at the region. So weathering and erosion take place resulting decomposition of rocks to silicon dioxide or sand,” said geologist Prof. Sisir Sen, former dean of I.I.T, Kharagpur.

The climatic condition of the deserts are extreme, days are too hot and nights too cold. This fluctuation in temperature leads to the weathering of rocks. Besides in an extreme hot desert sudden heavy rainfall disintegrates rocks to sand. Sometimes soluble salt in the rocks may form crystals due to high temperatures. These crystals create tremendous pressure on rocks and result disintegration of rocks to sand.

The question was sent by Malabika Tewari from Burdwan.