PROVENANCE OF THE BEACH SANDS BETWEEN
DAMIETTA AND PORT SAID AND THE EFFECTS OF
MARINE PROCESSES ON THEIR DISTRIBUTION
MOHAMED N. HASANEEN
Coastal Research Institute ,Alexandria, Egypt |
Combined grain-size and heavy mineral analyses were carried out on the beach sands between Damietta and Port Said during the year 2003. Also, the characteristics of the prevailing winds, currents and sea floor changes were determined. The beach sands are loose, fine to medium and moderately well-sorted. They are characterized by a heavy mineral assemblage dominated by opaques and the nonopaques :pyroxenes, amphiboles and epidotes; the latter constitute about 86% of the nonpaques. Zircon, monazite, garnet and tourmaline are subordinate to minor. The dominant heavy minerals having relatively lower specific gravity tend to concentrate in accreted areas. The areas of erosion, on the other hand, are characterized by the relative enrichment in the persistent heavy minerals.
Marine processes by waves and currents are highly active and in the absence of continuous supply of sediments, result in the erosion of the Damietta promontory. These currents transport sediments to the Damietta spit and along sediment sink west of Port Said. The net volume (accretion +/- erosion) change between the shore and the 6 m water depth was estimated to be ( -l.22 x 106 m3/ yr) in Damietta area and ( + 0.7 x 106 m3/ yr ) west Port Said. The lateral distributions of grain sizes and heavy minerals in the study area are conformable with the erosional and acretional pattern. They reflect the marked effects of the coastal processes involving wave-induced longshore currents and sediment transport.
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