Recent volcanism, tectonics and plate kinematics near the junction of the African, Arabian and Anatolian plates in the eastern Mediterranean

In the Eastern Mediterranean, plate convergence occurs between Africa-Arabia and Anatolia. The Africa/Arabia motion is a strike-slip displacement along the Dead Sea fault. The Africa/Anatolia motion is taken up by subduction south of Cyprus. The convergence between Arabia and Anatolia is taken up along the East Anatolian fault. The analysis of the regional fault surfaces reveals the presence of two major tectonic phases that affected southeastern Turkey near the junction of these three plates. The older deformations are related to a N-S compression. The more recent movements are directed mainly westward and associated with strike-slip and extension tectonics. Near the triple junction since 2 Ma, a fissure volcanism produced tholeiite followed by alkali basalt along the Amanos fault, the northern end segment of the Dead Sea Fault. In addition, reconstruction of rigid-plate kinematics between Arabia, Africa and Anatolia using recent plate motion parameters and space geodesy data suggest for the East Anatolian fault a slip rate of 7.8-9 mm/year. The maximum finite displacement recognised for this structure being around 15 km, we have obtained 1.9 Ma as the maximum age for the fault formation. The volcanic, tectonic and kinematic data converge to propose a ca. 2 Ma age for the change of local tectonic regime in the junction area. The structural mapping, the geometry of the fractures used by the magma to reach the surface and the presence of alkali basalt of mantle source suggest that the deformation along the northern end of the Dead Sea transform, i.e., the Amanos fault, was modified by the formation of the East Anatolian fault zone. In this region, apparition of the East Anatolian fault accommodating westward motion of the Anatolian plate resulted in oblique-slip tension along the Amanos segment of the Dead Sea transform, giving rise to a fissure-fed, mantle-derived alkaline volcanism at ca. 2 Ma, which lasted until recent times (0.4 Ma). (C) 1998 Elsevier Science B.V. All rights reserved.