The Ethiopian Flood Basalt Province

Abstract

The Ethiopian flood basalt province embraces the Afar triple-rift junction, where the African Rift System meets the Red Sea and Gulf of Aden sea-floor spreading zones. Prolific eruption of basalt and subordinate other lavas during Tertiary time has built up a subaerial volcanic pile, typically 500–1500 m thick and locally attaining 3000 m. This eruptive process was particularly active during mid-Tertiary, and was renewed in Afar some 5 My ago. The bulk of the eruptions was from fissures, and was intimately associated with the development of nascent continental margins defining the western and southern limits of Afar, within a larger context of Red Sea-Gulf of Aden basin evolution (Fig. 1). The Yemen Plateau basalts were united to their Ethiopian counterparts, prior to subsidence and opening of the Red Sea basin (see Civetta et al., 1978 and Capaldi et al., 1983 for aspects of the Yemen flood basalts).