Shallow structure and recent evolution of the Aegean Sea: A synthesis based on continuous reflection profiles

Abstract

A dense grid of continuous seismic reflection profiles, partly calibrated with drilling results, has allowed construction of a structural outline of the entire Aegean Sea. In the North Aegean we observe a clear difference between the thickly sedimented northern margin basins and the steep slopes of the trough margin of the southern North Aegean. The trough itself comprises a series of separate tectonic depressions resulting from an apparent transtensional motion. The Central Aegean consists of a complex tectonic puzzle caused by the prevailing extension; incipient strike-slip faulting (sub-parallel to the North Aegean trough trend) may, however, affect its eastern (Anatolian) domain. Three main structural areas characterize the Southern Aegean. Comparable structural directions cut across this chiefly extensional basin, but one fault system may be prevailing over the others, depending on the area. The Central Cretan Sea results from the interaction of at least two distinct extensions. These were superimposed on previous, mostly E-W structural trends generated during the inception of the southern Hellenic subduction and led to the present-day predominant SW-NE trending extension. As a hypothesis we propose that the overall Late Miocene-present evolution of the Aegean Sea is directly dependent on two geodynamic processes: to the southeast of the area, collision between Arabia and Turkey leads to the lateral (westward) expulsion of the Aegean continental crust, and to the west, Hellenic subduction is still active.