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Miocene extension in the back arc of the retreating Hellenic subduction zone resulted in metamorphic core complex formation and exhumation of the Cycladic HP‐LT rocks. The extension was accommodated by bivergent detachment systems, generally occupying the interface between the Cycladic Blueschist Unit (CBU) and overlying Pelagonian units. However, the nature and kinematic history of the contact between the CBU and underlying Cycladic Basement (CB) in the southern Cyclades remains debated due to the presence of both top‐to‐the‐N and top‐to‐the‐S kinematics and ambiguities dating the final exhumation stages. Zircon and apatite (U‐Th)/He data and thermal modelling for the CB and CBU on Ios and Sikinos show that both units were likely exhumed as a coherent footwall block in response to rapid slip along the bivergent Miocene Santorini and Naxos‐Paros detachment systems. [ABSTRACT FROM AUTHOR]

Detailed mapping and structural observations on the Cycladic Blueschist Unit (CBU) on Iraklia Island integrated with detrital zircon (DZ) U-Pb ages elucidate the Mesozoic pre-subduction and the Cenozoic orogenic evolution. Iraklia tectonostratigraphy includes a heterogeneous Lower Schist Fm., juxtaposed against a Marble Fm. and an overlying Upper Schist Fm. The contact is an extensional ductile-to-brittle-ductile, top-to-N shear zone, kinematically associated with the Oligo-Miocene exhumation. The DZ spectra of the Lower Schist have Gondwanan/peri-Gondwanan provenance signatures and point to Late Triassic Maximum Depositional Ages (MDAs). A quartz-rich schist lens yielded Precambrian DZ ages exclusively and is interpreted as part of the pre-Variscan metasedimentary Cycladic Basement, equivalent to schists of the Ios Island core. The Upper Schist represents a distinctly different stratigraphic package with late Cretaceous MDAs and dominance of Late Paleozoic DZ ages, suggestive of a more internal Pelagonian source. The contrast in the DZ U-Pb record between Lower and Upper Schist likely reflects the difference between a Paleotethyan and Neotethyan geodynamic imprint. The Triassic DZ input from eroded volcanic material is related to the final Paleotethys closure and Pindos/CBU rift basin opening, while late Cretaceous metamorphic/magmatic zircons and ~48–56 Ma zircon rims constrain the onset of Neotethyan convergence and high-pressure subduction metamorphism. [ABSTRACT FROM AUTHOR]