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Abstract I’ Soon after the Mid-Pleistocene regression, the subaerially exposed limestone was subjected to meteoric processes during which Mg-calcite was converted to stable low Mg-calcite and partial or complete dissolution of aragonite occurred at various depths. Early meteoric diagenesis through dissolution-precipitation processes had produced sparry calcite in the voids formed by the dissolution of aragonite in the limestone. Following the late Pleistocene-Holocene marine transgression, dolomitization was initiated in the reef in a meteoric-marine water mixing zone. Ebaid Alia (1988) studied the systematics, frequency distribution and ecology of Recent foraminiferal and molluscan shells in 100 samples collected from the intertidal (nearshore) and shallower areas (sub littoral) of the Red Sea along its western coastal plain between Marsa Alam and Ras Banas. Both groups of faunas provide much information on the environment in which they live. Abdel Aal and Hassan (1988) studied the chemical analysis of nine species of two gastropod families, Muricidae and Strombidae, collected from the Mediterranean Sea, Suez Canal and the Red Sea, in addition to, their shell wall structure. The wall structure of the studied shells indicated that the shells of every species consists of two or three layers of the following aragonite types: nacreous, prismatic and composite prismatic. Holail and Rashed (1992) studied the Recent beachrocks on the Mediterranean and the Red Sea coasts of Egypt. The Mediterranean beachrock skeletal particles (mainly molluscan fragments) are the most abundant grain type comprising approximately 60% of the framework grains; intraclasts make up the remaining 40%. In contrast, the Red Sea beachrock are dominantly composed of igneous and metamorphic crystalline basement rock fragments that range in dimension from large boulders in proximal parts of the fan to gravels, sands and silts in the distal parts. They concluded that, the oxygen and carbon isotopes, together with the texture and mineralogical composition of these cements are good indicators of the conditions of primary cementation and reflect the gross of stable isotopic and chemical composition of marine water. El-Moursib and Montaggionic (1994) studied the diagnosis of the Pleistocene reef- association sediments from the Red Sea coastal plain of Egypt. |