Along-strike variations of P-T conditions in accretionary wedges and syn-orogenic extension, the HP-LT Phyllite-Quartzite Nappe in Crete and the Peloponnese

Laurent Jolivet (1) , F. Trotet (2) , Patrick Monié (3) , Olivier Vidal (4) , Bruno Goffé (2) , Loic Labrousse (5) , Philippe Agard (5) , B. Ghorbal (1)

1 ISTO - Institut des Sciences de la Terre d'Orléans
2 LGENS - Laboratoire de géologie de l'ENS
3 Géosciences Montpellier
4 LGCA - Laboratoire de Géodynamique des Chaines Alpines
5 iSTeP - Institut des Sciences de la Terre de Paris

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.

Mots clés: High pressure and low temperature metamorphic rocks; Exhumation; Slab retreat; Detachment; Crete; Peloponnese

Domaines: Sciences de la Terre

Laurent Jolivet, F. Trotet, Patrick Monié, Olivier Vidal, Bruno Goffé, et al.. Along-strike variations of P-T conditions in accretionary wedges and syn-orogenic extension, the HP-LT Phyllite-Quartzite Nappe in Crete and the Peloponnese. Tectonophysics, 2010, 480 (1-4), pp.133-148. ⟨10.1016/j.tecto.2009.10.002⟩. ⟨insu-00411771⟩