Hazard impact and genetic development of sand dunes west of Samalut, Egypt

Abstract

A southeast mobile sand dune field extends west of the Nile Valley and encroaches on the cultivated land. These dunes have been investigated by geological and geomorphological mapping using Landsat ETM images and field work. Fifty sand samples had been collected from sand dunes and five samples from substratum. The laboratory investigations involve granulometric parameters using binocular microscope and carrying out the collective diagrams and granulometric indices. Morphoscopic studies using Scanning Electron Microscope (SEM) elucidate the surface process affected on sand grains. These dunes have their source from Oligocene sand and gravel deposits to the north of the study area and from the substratum. While the sands are shiny and more rounded mat grains in the northern part of these dunes due to fluvial processes, the south sands become more markedly “aeolinized” by including less rounded and striated sand grains. They move and increase in size in the down wind direction. The initiation of linear dunes explanted here west of the Nile Valley where the eastern tails of the lee side of the barchan dunes are longer than the western ones and sometimes these tails are connected with each other forming longitudinal sand dunes. These dunes are in mature stage and the southern dune may be in the last modification stage.

Keywords

• Sand dunes
• Aeolian
• Grains