Duration, thermal regime and argon behavior in continental shear zones: a synthesis from the Aegean domain, Menderes Massif and Alpine Corsica

Large continental shear zones play a fundamental role in crustal deformation, exhumation and lithosphere-scale tectonics, yet their duration of activity and the controls exerted by thermal regime on their geochronological record remain debated. Over the past decade, studies conducted in the Aegean domain, Menderes Massif and Alpine Corsica have generated a large and internally consistent set of geochronological data acquired across several major shear-zone systems. These datasets are dominated by ⁴⁰Ar/³⁹Ar ages complemented by U–Pb, Rb–Sr and low-temperature thermochronology.

Here we propose a synthesis of these datasets, integrating published results from different types of shear zones developed under contrasting P–T conditions, ranging from cold HP–LT subduction zone to Barrovian metamorphism in collisional environment and hot metamorphic core complex settings. We aim to compare age–distance relationships across shear zones, assess the temporal distribution and duration of deformation events recorded by argon systems, and place these observations in a broader tectono-thermal framework. Preliminary observations suggest systematic differences between cold and hot shear zones: cold systems tend to preserve a broad spectrum of argon ages spanning most of the deformation history, whereas hot shear zones commonly record shorter durations and younger ages biased toward the final stages of activity. These patterns appear to be robust across different tectonic settings and may reflect fundamental differences in deformation mechanisms, fluid circulation and argon mobility.

By combining shear-zone geochronology with independent constraints from magmatic intrusions, partial melting and tectono-metamorphic evolution, this synthesis identifies common timescales for shear-zone activity and clarifies how thermal regime controls both deformation processes and the geochronological record. Beyond regional implications for the dynamics of the Aegean and surrounding domains, this study provides first-order constraints on the mechanisms and longevity of continental shear zones and on the interpretation of geochronological datasets acquired in deformed rocks.