Résumé
Lavas from the Ethiopian Plateau, mainly 30-10 m.y. old, show synchronous eruption of incompatible element-poor tholeiites and incompatible element-rich alkalic lavas with wide ranges of Pb isotope compositions and transition from tholeiite to alkali magmatism during continental rifting. The lithospheric mantle played only a passive role and was not the source of these magmas which is comparable with the broad region of mantle upwelling in the S. Pacific Ocean that formed the volcanic islands of French Polynesia. Melting in large hotter-than-average parts of the Ethiopian Superswell produced the flood basalts and melting of small diverse regions produced the magmas that fed the Shield volcanoes. An extensive database of 100 major, trace and REE analyses of basalts, trachybasalts, trachytes, rhyolite, trachyandesite and dacite plus Sr, Nd and Pb isotopic analyses, is listed.