ABSTRACT
Shrinkage cracks are widespread in the soils of the eastern Sahara. They even occur in sandy material and attain considerable dimensions. A comparative study of natural cracks and cracks produced under laboratory conditions indicates that cracks formed in sand are the result of desiccation rather than temperature fluctuations. Very deep and wide cracks in sandy material are regarded as indicators of extremely arid climatic conditions. Some of the cracks have undergone several stages in their formation. They are generally infilled by aeolian sand, but material mobilized by surface wash processes can also result in their infilling. Surficial water tends to infiltrate into the ground via such cracks.
