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The recent discovery of HP-LT parageneses in the basal unit of the Lycian nappes and in the Mesozoic cover of the Menderes massif leads us to reconsider and discuss the correlation of this region with the nearby collapsed Hellenides in the Aegean domain. Although similarities have long been pointed out by various authors, a clear correlation has not yet been proposed and most authors insist more on differences than similarities. The Menderes massif is the eastern extension of the Aegean region but it has been less severely affected by the Aegean extension during the Oligo-Miocene. It would thus be useful to use the structure of the Menderes massif as an image of the Aegean region before a significant extension has considerably reduced its crustal thickness. But the lack of correlation between the two regions has so far hampered such comparisons. We describe the main tectonic units and metamorphic events in the two regions and propose a correlation. We then show possible sections of the two regions before the Aegean extension and discuss the involvement of continental basement in the Hellenic accretionary complex. In our interpretation the Hellenic-Tauric accretionary complex was composed of stacked basement and cover units which underwent variable P-T histories. Those which were not exhumed early enough later followed a high-T evolution which led to partial melting in the Cyclades during post-orogenic extension. Although the Menderes massif contains a larger volume of basement units it does not show significant evidence for the Oligo-Miocene migmatites observed in the center of the Cyclades suggesting that crustal partial melting is strictly related to post-orogenic extension in this case. Corrélation des événements tectoniques et métamorphiques syn-orogéniques dans les Cyclades, les nappes Lyciennes et le massif du Menderes, implications géodynamiquesMots-clés. -Egée, Turquie, Hellenides, Taurides, Cyclades, Menderes, Complexe d'accrétion, Métamorphisme de haute-pression.Résumé. -La découverte récente de paragenèses de haute pression et basse température dans les unités de bases des nappes lyciennes et la couverture mésozoïque du massif du Menderes nous conduit à reconsidérer et discuter les corréla-tions entre cette région et le domaine proche des Hellenides écroulées de la mer Egée. Bien que des similitudes aient été notées par de nombreux auteurs des corrélations claires n'ont pas encore été proposées et on insiste encore aujourd'hui plus sur les différences que sur les ressemblances. Le massif du Menderes est la prolongation orientale de la région des Cyclades mais il a été moins sévèrement affecté par l'extension égéenne pendant l'Oligo-Miocène. Il peut être alors très utile d'utiliser la structure du Menderes comme une image de ce qu'était l'Egée avant qu'une extension considérable n'y ait réduit de manière importante l'épaisseur crustale. Mais le manque de corrélation rend difficile de genre de comparaison. Nous décrivons les principales unités tectoniques et les événements métamorphiques des deux régions...

30-35 Ma ago a major change occurred in the Mediterranean region, from a regionally compressional subduction coeval with the formation of Alpine mountain belts, to extensional subduction and backarc rifting. Backarc extension was accompanied by gravitational spreading of the mountain belts formed before this Oligocene revolution. Syn-rift basins formed during this process above detachments and low-angle normal faults. Parameters that control the formation and the kinematics of such flat-lying detachments are still poorly understood. From the Aegean Sea to the Tyrrhenian Sea and the Alboran Sea, we have analysed onshore the deformation and P-T-t evolution of the ductile crust exhumed by extension, and the transition from ductile to brittle conditions as well as the relations between deep deformation and basin formation. We show that the sense of shear along crustal-scale detachments is toward the trench when subduction proceeds with little or no convergence (northern Tyrrhenian and Alboran after 20 Ma) and away from the trench in the case of true convergence (Aegean). We tentatively propose a scheme explaining how interactions between the subducting slab and the mantle control the basal shear below the upper plate and the geometry and distribution of detachments and associated sedimentary basins. We propose that ablative subduction below the Aegean is responsible for the observed kinematics on detachments (i.e. away from the trench). The example of the Betic Cordillera and the Rif orogen, where the directions of stretching were different in the lower and the upper crust and changed through time, is also discussed following this hypothesis.

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