Constraints on the Neogene Mediterranean kinematic evolution along a 1000 km transect from Iberia to Africa

Abstract

Abstract We present in this paper a simple kinematic model to illustrate the evolution of the western Mediterranean since upper Oligocene times. The five-step mass balanced reconstructions of the region are constructed along a 1000 km long crustal-scale transect from Iberia to Africa across the València and Algerian basins. The model uses constant divergence and convergence rates and fits the geological and geophysical data well along the transect. The amount of convergence and divergence along the studied transect can be resolved by the combination of two tectonic mechanisms: the northern motion of the African plate and the southwards retreat of a subducting Tethyan oceanic slab located between the pre-Neogene Iberian and African margins. The evolution of the western Mediterranean region during the last 30 Ma can be summarized as follows: (a) pre-Neogene (late Oligocene) Iberian and African margins separated by a north-dipping fragment of Tethyan oceanic crust; (b) widespread extension affecting the Iberian margin developing the València trough and the Algerian basin from upper Oligocene to the top of Langhian; (c) end of the formation of the València trough and the collision between the Kabylies and Africa domains at c. 13 Ma; (d) end of the Algerian basin opening and northern Kabylies and Tellian thrust systems coupled tectonic domains in the upper Tortonian (8 Ma); (e) shortening within the whole domain by the northwards motion of Africa after late Tortonian times. The propagation of stress within the western Mediterranean region seems to affect the whole region as far north as the northern side of the Pyrenean range located a distance of 1200 km from the south Atlas front, the southern limit of the system.