Lateral variations of pressure-temperature evolution in non-cylindrical orogens and 3-D subduction dynamics: the Betic-Rif Cordillera example

The long-term Pressure-Temperature-time-deformation ( P-T-t-d ) evolution of the internal zones orogens results from complex interactions between subducting lithosphere, overriding plate and intervening asthenosphere. 2-D numerical models successfully reproduce natural P-T-t - d paths, but most are non-cylindrical situation is far more due to 3-D pre-orogenic inheritance subduction dynamics. Mediterranean intrinsically non-cylindrical. Their geometry shape Eurasian African margins before convergence dynamics slab retreat tearing leading strongly arcuate belts. More than many other segments, Betic-Rif belt archetypal this behavior. A synthesis tectonometamorphic Internal Zones, also based on recent findings by our group in framework Orogen Project (Alboran domain, including Alpujárride-Sebtide Nevado-Filábride complexes) shows relations space time tectonic P-T evolutions. reinterpretation contact peridotite massifs Mesozoic sediments as an extensional detachment leads a discussion geodynamic setting timing mantle exhumation. Based new 40 Ar/ 39 Ar ages published complex, we conclude that age H P -L T metamorphism Eocene all complexes. first-order observation contrast well-preserved blueschists-facies rocks eastern Complex younger conditions reaching partial melting recorded Western Alpujárride. We propose model where large longitudinal variations mainly (i) differences exhumation, (ii) nature lithosphere (iii) major change at ∼20 Ma associated with slab-tearing event. clustering radiometric obtained different methods around 20 regional exhumation episode coeval tearing, westward migration trench, back-arc extension thrusting whole orogen onto Iberian margins.