The structural evolution of central Crete: insight into the tectonic evolution of the south Aegean (Greece)

Abstract

The recognition of crustal extension as a major mechanism of deformation of Crete and south Aegean region during Late Alpine times greatly clarifies the tectonic evolution of the area. Detailed structural analyses of the nappes of central Crete have enabled the tectonic evolution of the island, during Late Alpine times, to be reconstructed. Structural analyses of the upper nappes of Crete, which are similar to those of the Cyclades islands and were metamorphosed in pre-Oligocene time, also allows the tectonic evolution of Crete to be correlated with the better-known tectonic evolution of the Cyclades area. This history can be summarised as follows: In the Palaeocene–Eocene, ophiolites and the previously metamorphosed and deformed in the Late Cretaceous (D 1u) Asteroussia nappe constituted the hangingwall plate during subduction and the formation of HP rocks in the Cyclades. During the Late Eocene–Early Oligocene, possibly during the early extension of the Cyclades, crustal masses extruded toward the outer area of Crete probably accelerated the westward stacking (D 2u) of the developing nappes. In the Late Oligocene–Early Miocene, compression in the area of Crete became southward-directed (D 3), causing the subduction of the lower nappes and the southward stacking of the upper nappes. In the Cyclades, extension and southward escape of crustal masses continued. In the Miocene, crustal extension in Crete (D 4) caused the exhumation and uplift of the lower HP–LT metamorphosed nappes, while compression migrated southward to an external area, probably forming the Active Hellenic Subduction Zone (AHSZ). Finally, a Late Miocene–Early Pliocene (D 5) compression affected Crete, probably because of the lateral convergence of the European and African plates and initiation of the escape of the Turkish plate. Thus, the intensity and duration of deformation in the Cyclades area controlled and governed the structural evolution of Crete.