Age of the lower flood basalts of the Ethiopian plateau

Abstract

VARIOUS stages of continental fracturing and crustal separation are displayed in Ethiopia at present. Separation of the African and Arabian plates has taken place along the Red Sea and Gulf of Aden rifts and in several areas of Afar where axial volcanic ranges are composed of low-potassium oceanic tholeiites1. The onset of spreading was accompanied by deep faulting and intense fissural activity, with the eruption of very fluid flood basalts over Mesozoic sediments and Precambrian basement. The flood basalts outcrop on the plateaux flanking the rift system (Fig. 1).