Talc-carbonate rocks of Central Eastern Desert as a natural magnesia source: characterization and evaluation

The huge talc-carbonate masses at Barramiya area and Wadi Atalla are the largest outcrops in the Central Eastern Desert. They are genetically and spatially associated with serpentinite in sequences of ophiolitic melange. The talc-earbonate masses were formed at expense of serpentinites as resultant of carbon dioxide metasomatism along fault planes, fractures and contacts against the regionally metamorphosed (greenschist up to middle amphibolite facies) country rocks. These characteristic and practically unused raw materials could serve as possible natural magnesia source for a wide spectrum of industrial applications such as metallic, chemicals and refractories. Applying the GIS techniques, the different ophiolitic components of the studied areas were successfully distinguished from each other. Thus, the studied talc-carbonate masses were reasonably separated as separate layers on a scale of 1:20.000 using the RGB band ratio image enhancement and the Landsat TM supervised classified image. Consequently, the ore reserve calculations for each locality was accomplished and proved to exceed hundreds thousands of tons. Petrography, XRD, XRF and EDAX analyses were achieved. Accordingly, they were distinguished into assemblages of talc and magnesite as the main constituents in variable proportions. The accessories are dolomite, serpentine minerals, iron oxides, chlorite, amphiboles and phlogopite. Complementary to the present study and based on the current geologic data, an assessment of the more suitable samples to produce cordierite and/or foresterite as refractories will be addressed latter on.