Correlation of syn-orogenic tectonic and metamorphic events in the Cyclades, the Lycian nappes and the Menderes massif. Geodynamic implications

Abstract

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...

Kinematic reconstructions and magmatic evolution illuminating crustal and mantle dynamics of the eastern Mediterranean region since the late Cretaceous

“…Ring et al, 1999b;Bozkurt & Oberhänsli, 2001;Gessner et al, 2001aGessner et al, , 2013Jolivet et al, 2004b]. Following this accretionary event, this massif has been exhumed in a back-arc extensional context, forming a dome-like structure [e.g.…”

Thrust or detachment? Exhumation processes in the Aegean: Insight from a field study on Ios (Cyclades, Greece)

“…However, the structures related to this episode are severely overprinted on most islands. It prevents from unraveling a clear kinematics for synorogenic exhumation at regional scale [Jolivet et al, 2004b]. Nevertheless, coherent structures on Syros and Sifnos islands show that exhumation was accommodated by a continuous extension from ductile to brittle and from blueschist to greenschist facies conditions [Trotet et al, 2001a[Trotet et al, , 2001b.…”

“…This gradient is coeval with a Figure 15. (a) Tectonic map of synorogenic and postorogenic structures in the Cyclades, modified after Jolivet et al [2004b]. The thin arrows indicate the ductile sense of shear associated to the Oligo-Miocene extensional episode [Lister et al, 1984;Faure et al, 1991;Brun, 1994b, 1994a;Vandenberg and Lister, 1996;Forster and Lister, 1999a;Jolivet and Patriat, 1999;Mehl et al, 2005Mehl et al, , 2007M.…”

“…[60] On most Cycladic islands (Figure 15a), the OligoMiocene extensional reworking of the nappe stack erased most of the Eocene kinematic indicators [Jolivet et al, 2004b]. However, on Syros and Sifnos islands the synorogenic kinematics is preserved.…”

Exhumation with a twist: Paleomagnetic constraints on the evolution of the Menderes metamorphic core complex, western Turkey

“…No late Oligocene to early Miocene core complexes are known east of this boundary. The western limit of the NMM is also a discrete lineament, but to the west of this lineament evidence for early Miocene extension is widely present, e.g., in the Kazdağ massif [Okay and Satir, 2000;Bonev et al, 2009;Cavazza et al, 2009] (Figure 3) and in the Cyclades [Gautier et al, 1999;Ring et al, 1999b;Jolivet et al, 2004;Tirel et al, 2009;Jolivet and Brun, 2010].…”