Seismic Character As A Tool To Identify Different Geotectonic Zones In The Frontier Area Offshore South Of Crete, Greece

Abstract

Although the geotectonic zones in western Greece are clearly thrusted on top of each other from east to west, in Crete these nappes are piled up cropping out thanks to tectonic windows. In western Greece, the Ionian islands provide a lot of information with regards to the most external parts of the Hellenides Thrust-and-Fold Belt (TFB). In addition, several wells and a dense seismic grid confirm the geological knowledge of the area and mitigate the uncertainty about the petroleum system there. In contrast, the area south of Crete includes only four (4) very small islands providing scattered information of the geological setting in the Cretan margin, along with a sparse seismic grid and the lack of wells. Despite more than forty (40) years of geological and geophysical work in the region, the geodynamic and tectonic processes have been debatable and controversial. An initial attempt to distinguish and outline the geotectonic zones present in the area south of the island of Crete has been done based on the integration of seismic data and onshore geology. However, because of the above-mentioned limitations the attempt remains speculative. The use of the seismic data allowed for a more accurate mapping of the three (3) distinct geological areas south of Crete; Cretan margin, Backstop and Mediterranean Ridge. The Cretan margin includes stacked nappes similar to those onshore Crete, the Backstop includes probably the most external Hellenides, while the Mediterranean Ridge cannot be assigned to any of the known Hellenides.