Extensional deformations in Yemen since Oligocene and the Africa- Arabia-Somalia triple junction

The geometry and chronology of the successive extensional tectonic events which affected part of the triple junction between the Africa, Arabia and Somalia plates are described. E-W extension prevailed during the Oligocene and early Miocene and was associated with the emplacement of the Yemen Volcanics. From 22 to 18 Ma ago, the uppermost part of the Yemen Volcanics was emplaced under a N-S trending extension related to the increasing influence of the proto-Gulf of Aden continental rift. Finally, Yemen was submitted to NE-SW extension between 18 and 10 Ma, around the time of acceleration of rifting and subsequent oceanization of the Red Sea and Gulf of Aden. This phase of extension is sealed in the southernmost part of Yemen by late Miocene basaltic series. The relationships between deformation and kinematics are discussed. -from Authors