Triassic Evaporites On- and Offshore Western Greece and their Significance in Hydrocarbon Exploration

Abstract

Summary Triassic evaporites on- offshore western Greece are of great significance for the tectonic evolution of the sedimentary basins and the accumulation of hydrocarbons. They build the basis of the Alpine nappes and are the lubricants for the westwards motion of these units. They separate the upper (Alpine) from the lower (Preapulia) part of the sedimentary sequence and are the seals and traps of hydrocarbons generated during the Triassic. These basins have significant thickness (8 to 12 km) and are difficult to penetrate and map with conventional seismic methods. We have explored them with wide aperture techniques. The backstop areas to the west are composed of stretch continental crust. Sedimentary basins are much thinner than those of western Greece and the Triassic evaporites are absent. This is also the case for the basins southwest of Crete. Sediments range from 3 to 6 km and Triassic evaporites are absent. Structures of interest for oil exploration southwest of Crete occur at a distance of approx. 150 km from the coast, at the Mediterranean Ridge. Sediments are very thick (10 to 14 km) and are strongly tectonized. The existence of mud volcanoes is a direct indicator for hydrocarbon systems.