Zabargad peridotite; evidence for multistage metasomatism during Red Sea rifting

New analyses of rare earth elements (REEs) and abundances of K, Rb, Sr, Ba, Th, U, Ta, and Hf in peridotites from Zabargad Island, Red Sea, indicate that light REE-enriched amphibole peridotites in the northern and central bodies have undergone a complex, multistage, metasomatic history during Red Sea rifting. The metasomatism is partly attributed to the passage of alkalic basalts through the mantle lithosphere, which possibly occurred during the early, continental-rift history of the Red Sea. The metasomatism also results from the interaction of the uppermost lithosphere with hydrous crustal fluids released from thinning continental crust. The last metasomatic event is associated with the development of an oceanic hydrothermal system in the Red Sea, after the continental breakup. The available data also suggest that the Zabargad peridotites represent pieces of pan-African lithospheric mantle (the northern and central bodies) pierced by asthenospheric material (the southern body).