Geological setting

The complicated nappes pile of the Crete Island have been stacked successively during the Alpine orogenic processes, from Jurassic to Miocene time (fig. 2), recording a multi-stage structural evolution. A major compressional regime has determined the evolution of the nappes stacking. Initially, the tectonic upper nappes (fig. 2, 3) were emplaced, successively followed by the other tectonic nappes from up towards down, with a SSW sense of movement. The whole tectonic nappes pile was finally emplaced on the lower nappes system, undergoing high pressure metamorphism during Upper Oligocene - Lower Miocene, through subsidence in a depth greater than 30km (fig. 2, 3, Seidel et al., 1982).

Compression and nappe stacking were followed during Lower-Middle Miocene by a N-S collapse, tectonic thinning and extensional exhumation of the tectonic lower high-pressure nappes. These nappes emerged in a series of tectonic windows, while tectonic horsts and rather than subsidence subsequently evolved (Fassoulas et al., 1994, Kilias et al., 1994, 2002). The lower tectonic nappes were affected by ductile deformation, while the upper tectonic nappes by brittle low-angle extensional shear zones, respectively (Kilias et al., 1994, Fassoulas et al., 1994, Jolivet et al., 1996). During this period, the first Neogene basins of the island were formed, often bordered by major syn-sedimentary normal boundary faults (fig. 4; Freudental 1969, Frydas & Keupp 1996). The main compression migrated southwards towards the Mediterranean ridge, where the present active subduction zone of the Eastern Mediterranean lithosphere beneath the Aegean microplate is currently taking place.

The extensional tectonic regime after Middle Miocene is characterized by an initial almost N-S sub-horizontal extension and simultaneous thinning of the crust. Younger neotectonic faults followed this tectonic process in Crete, due to the ongoing active Southern Aegean subduction.

Figure 2. Geological map indicating the tectonic lower and upper nappes of the Crete nappes pile

Geological map indicating the tectonic lower and upper nappes of the Crete nappes pile

(modified from Kilias et al. 1994).

Figure 3. The complicated tectonic nappes pile of Crete

The complicated tectonic nappes pile of Crete

(modified from Seidel et al. 1982).

Figure 4. Lithostratigraphic column of the Neogene in Western Crete

Lithostratigraphic column of the Neogene in Western Crete

(modified from Freudental 1969 and Frydas & Keupp 1996).