SURFACE TEXTURES OF QUARTZ GRAINS FROM RECENT SEDIMENTARY ENVIRONMENTS ALONG THE MEDITERRANEAN COAST, EGYPT

This study identifies the assemblages of quartz-grain surface textures in sands from five Recent environments along the Mediterranean coast and adjoining desert regions of Egypt. The results of this study, using the scanning electron microscopy (SEM) reveal the existence of several surface features that reflect the effect of mechanical and chemical action on the studied quartz grains. Quartz grains of beach, nearshore, coastal dune and desert sand sheets show an abundance of both mechanical and chemical surface features developed during transportation of the grains in the subaqueous and aeolian environments respectively. On the other hand, sand grains from sabkha sediments are characterized by the dominance of chemical surface features. Among chemically produced surface features, those originating from silica dissolution are considerably more numerous than those due to silica precipitation. Relative frequency distributions of the various surface features recorded on quartz grains from different environments indicate a considerable overlap in the types of surface feature from beach sands and nearshore sands to coastal dune sands and vise versa, as might be expected in this system where sediment has been recycled between markedly dune and coastal marine settings.