Petrogenesis of the Tarr albitite-carbonatite complex, Sinai Peninsula

Large albitite bodies associated with explosive brecciation, fenite aureoles, intrusive carbonate rocks, olivine dolerites, and copper mineralization are described from the Dead Sea rift region in the south-eastern Sinai Peninsula. The main carbonate phases comprise breunnerite and dolomite with actinolite the main phase in the fenites. Field and isotopic evidence indicates that the intrusive carbonate rocks are of carbonatitic origin. The cogenetic, almost monomineralic main phases can be attributed to fractional crystallization and liquid immiscibility acting on a highly gascharged, slow-cooling gabbroic magma. The complex, which is probably of Cretaceous (or older) age, appears to be related to early continental separation along the Dead Sea branch of the African rift system. The porphyry-type copper deposits resemble others that are located along crustal accretion (Iceland) or subduction (Chile) zones.