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The spatiotemporal scales at which fluid flow events occur along the subduction interface remain poorly constrained. This study illustrates the benefit of using in‐situ Rb/Sr dating on metasomatic white mica to constrain the timing of metasomatic events, taking advantage of the well‐studied reaction zones of the Kampos‐Lia unit of Syros, Greece. This unit is a subducted block‐in‐matrix structure corresponding to a preserved fragment of a discontinuous, slow‐spreading oceanic domain. Results reveal that the main metasomatic event took place at ~36 Ma, coincident with the transition from blueschist to greenschist facies and syn‐ to post‐orogenic exhumation in the Cyclades marking the end of a first exhumation stage along the subduction interface. Results highlight that fluid–rock interaction along the subduction interface cannot be treated as the result of continuous fluid influx, but rather reflect punctuated, heterogeneously distributed events (both in time and space) tied to specific tectonometamorphic episodes. [ABSTRACT FROM AUTHOR]

Abstract: The Corinth Rift is superimposed on the Hellenic nappe stack that formed at the expense of the Apulian continental crust above the subducting African slab. Extension started in the Pliocene and the major steep normal faults that control the geometry of the present-day rift were born very recently, some 600kyr ago only. They root into a shallow-dipping zone of microseismicity recorded near the base of the upper crust. The significance of this seismogenic zone is debated. Considering the northward dip of the zone of microseismicity, the depth of microearthquakes and their focal mechanisms, we observe a strong similarity with the northern Cycladic detachments in terms of expected pressure, temperature conditions and kinematics. We herein show (1) that the formation of the Corinth Rift can be considered a part of a continuum of extension that started some 30–35Ma in the Aegean and that was recently localised in a more restricted area, (2) that the present-day structure and kinematics of the Corinth Rift can be explained with a series of decollements relayed by steeper ramps that altogether formed a mechanically weak, crustal-scale detachment, and (3) that the deformation, fluid behaviour and metamorphic features seen in the northern Cycladic metamorphic core complexes can be good analogues of the processes at work below the Corinth Rift. [Copyright &y& Elsevier]

Abstract: Syn-orogenic detachments in accretionary wedges make the exhumation of high-pressure and low-temperature metamorphic rocks possible with little erosion. The velocity of exhumation within the subduction channel or the accretionary complex, and thus the shape of P–T paths, depend upon the kinematic boundary conditions. A component of slab retreat tends to open the channel and facilitates the exhumation. We document the effect of slab retreat on the shape of P–T paths using the example of the Phyllite–Quartzite Nappe that has been exhumed below the Cretan syn-orogenic detachment during the Miocene in Crete and the Peloponnese. Data show a clear tendency toward colder conditions at peak pressure and during exhumation where the intensity of slab retreat is larger. This spatial evolution of P–T gradient is accompanied with an evolution from a partly coaxial regime below the Peloponnese section of the detachment toward a clearly non-coaxial regime in Crete. [Copyright &y& Elsevier]