Résumé
Mantle-derived rocks that outcrop on Zabargad Island represent the upper part of a diapir emplaced during the early stages of Red Sea rifting. These rocks underwent several metasomatic events. Leaching experiments and Sr-Nd isotopic data on whole rocks and peridot megacrysts provide new information on the last hydrothermal event. These data are consistent with a widespread infiltration of high-T sea-water.