Studies of the geochemical, mineralogical, petrographical characteristics and the physicochemical properties were carried out on some Miocene Abu Sir ridge limestones, to throw light on the possibility of utilizing them as a building stone. The carbonate rocks of El-Omayid and El-Hammam quarries at North Western Coastal area have potential application in building, industry and purification of the environment. Petrographically, the carbonate deposits of the El-Omayid section are grainstone and wackestone/packestone microfacies while those of El-Hammam section are wackestone/packestone and mudstone/wackestone microfacies. They are deposited in shallow marine environment. Mineralogically, XRD and DTA revealed that the carbonates of the two quarries consist mainly of calcite and aragonites, besides quartz, anhydrite, halite and dolomite as minor constituents. Geochemically, they have very high Ca content; however, are impoverished in Na2O, K2O, Al2O3, Fe2O3 and SiO2. The total radioactivity measurements range from 5 to 14 ppm with an average of 7 ppm. The radioactivity measurements are approximately against the background level of limestone, and they are in the permissible limits for limestone used in cement industries and as building stones. The limestone rocks of the two quarries are proved chemically suitable for the industries relevant to lime production and cement. Physical-mechanical examination revealed that the carbonates of the two quarries increase in porosity and water absorption with decreasing crushability, bulk density and compressive strength. The petrographic, chemical and physical-mechanical observations recommended the utilization of the carbonate deposits of the two quarries in mechanical swing and production of limestone blocks and unsuitable for concrete aggregates.
