Kinematics of the Danakil microplate

A refinement and extrapolation of recent motion estimates for the Danakilmicroplate, based on ancient kinematic indicators in the Afar region, describesthe evolution of a microplate in the continental realm. The Danakil horst is anelevated part of this microplate, exposing Precambrian basement within theAfar depression, site of the Nubia-Somalia-Arabia triple junction. We compareevidence for strike- or oblique-slip faults in data from the Afar depression andsouthern Red Sea to small circles about published instantaneous poles ofrotation for the Danakil microplate with respect to Nubia. A reconstructionabout the preferred pole reunites lengths of a Precambrian shear zone on theNubian and Danakil sides and preserves a uniform basement strike throughNubia, Danakil and Yemen. Since at least magnetic chron C5 (~11 Ma) Danakilrotated about a different pole with respect to Nubia than either Somalia orArabia, but between chrons C5 and C2A Nubia-Danakil motion was a closeapproximation to Nubia-Somalia motion. Since C2A relative motions of theDanakil microplate have been independent of movements on any of theneighbouring plate boundaries. We relate this to the onset of oceanic-typeaccretion within Afar. The resulting eastwards acceleration of Danakil wasaccommodated by westwards propagation of the Gulf of Aden rift that becamethe new, discrete, plate boundary between the Danakil microplate and theSomalia plate. Present day activity suggests that the Red Sea and Aden riftswill link through Afar, thereby isolating the Danakil horst as a microcontinenton the Arabian margin.