Anatomy and evolution of a migmatite-cored extensional metamorphic dome and interaction with syn-kinematic intrusions, the Mykonos-Delos-Rheneia MCC

摘要: Post-orogenic extension in back-arc regions is classically associated with metamorphic core complexes (MCCs) cored exhumed rocks and granitic intrusions interacting low-angle detachments. When additional heat provided by the advected asthenosphere below extending region, for instance above slab tears, high-temperature migmatite-cored domes composite are emplaced whose geometry kinematics of emplacement controlled regional The Cyclades Archipelago (Aegean Sea) hosts several such Miocene MMCs intruded granitoids, offering windows open on interactions Livada Mykonos detachments, two branches North Cycladic Detachment System. Deformation System has been described detailed based a structural study deformation pluton, but gneiss MCC root zone intrusion have received little attention. Based field surveys neighboring islands Rheneia Delos, we propose this paper new geological map show that locally migmatitic extends from to Apollonia peninsula Mykonos, topped 500 meters-thick shear zone, Shear Zone, coeval series granitoids evolving granodiorite monzogranite. Zone shows progressive flattening shearing, constrictional component, during numerous fine-grained felsic dykes at various stages totally transposed become parallel main foliation. intensely stretched an E-W trending lineation folds axes lineation. Structural compatibility between migmatites rheological parameters were not much different time intrusion. same continued cooling dome while batches material colder gneiss. granites syn-kinematic stretching magmatic stage after cooling, leading full homoaxiality fabric mylonites Detachment. From lower crustal partial melting subsequent mylonitization formation brittle detachment, deposition supra-detachment sediments late baryte-iron dykes, observed until change stress regime some 9 Ma ago. Mykonos-Delos-Rheneia illustrates continuous detachment system growing pluton how discrete event can be influenced long-term tectonics.