Evolution of the Danakil Depression (Afar, Ethiopia) in Light of Radiometric Age Determinations

Fourteen new K/Ar and fission-track ages obtained on volcanic rocks from the Danakil depression are presented. Together with previous data, they allow a preliminary reconstruction of the volcanic evolution of the northern Afar (Danakil) rift. Independent age determinations indicate that the Danakil rift began to form in the lower Miocene (23-25 m.y. B.P.). Since then and up to the present day, volcanism has been almost continuous producing rock associations of contrasting origin according to the tectonic nature of the areas involved. The development of axial volcanic ranges of subcrustal origin, marking the evolution from a continental to an oceanic rift by means of separation of the sialic crust probably took place only very recently (less than 1.2 m.y. B.P.).