Petrogenesis of Barramiya talc-carbonate rocks, Central Eastern Desert, Egypt

Citation

Ali-Bik MW, Taman Z, El Kalioubi B & Wahab Ibrahim WA (2010) Petrogenesis of Barramiya talc-carbonate rocks, Central Eastern Desert, Egypt. Sinai International Conference for Geology and Development (SICGD), 01.2010-01.2010.

Abstract
Tremendous quannues of practically untapped talc-carbonate rocks are distributed in Barramiya area in intimate - spatially and genetically association with the ophiolitic serpentinites, These deposits could serve as an important potential source of magnesia which is used in a broad spectrum of strategic industries. Barramiya ophioliuc serpentinites represent obducted oceanic slices onto island-arc success ions. They occur as elongated mountainous ranges in the form ofanticlinal-synclinal sheets demarcating the general ENE·WSW brittle-ductile shear zone of the area. The serpentinite-hosted talc-carbonate deposits ofBarramiya area are located: a) either along major faults that cut the serpentinite slices or b) at thrust contacts between abducted serpentinites and other melange components (more siliceous country rocks of island-arc affinity). The latter were regionally metamorphosed in greenschist up la middle amphibolite facies, Barrarniya talc-carbonate rocks represent in situ fissure-fed rnetasomatie products of serpentinite precursors via extensive rock-fluid interactions. The main fluids that involved in transformation processes ofserpentinites to talecarbonates wereSiO2 aquous and CO2. In general, the deposits located along fault system that cut the sesperuinites host are magnesite-rich, whereas those located at the contacts between serpentinnes and the more siliceous country rocks are typically talc-rich. Talc and magnesite as the main constituents of Barramiya talc-carbonate rocks occur in variable proportions. Hence, the rocks were distinguished into assemblages according to the predominance of these phases in conjunction with the other accessories such as dolomite, quartz and serpentine minerals. In the present work, petrogenesis of Barramiya talc carbonate rocks and their evolution courses from serpentinite precursors are elaborated in the light of their petrography, mineralogy, mineral chemistry and geochernistry, Using remote sensing and GIS techniques, the Barramiya talc-carbonate rocks Were reasonably mapped as separate layers and their reserve estimations (possible and proved) were accomplished.