Quaternary sedimentary history and neotectonic evolution of the eastern part of Central Aegean Sea, Greece

Abstract

Four distinct unconformities can be traced below the E. Cyclades margins (S. Ikarian Basin), that separate four oblique progradational delta sequences. These have been deposited during sea-level lowstands within Middle-Late Quaternary glacial stages (oxygen isotopic stages 2, 6 and possibly 12-8, 22-16). The topset-foreset transition of these sequences, located at 110, 152 and 212 m below present sea level, reflect continuous subsidence of the S. Ikarian margins, with a calculated rate of 0.33–0.57 m kyr −1. The mean sedimentation rates were estimated as 20–90 cm kyr −1 for the Late Pleistocene turbiditic deposits (250 kyr B.P.-today). For the post-isotopic 6 (128 kyr B.P.-today) sediments the accumulation rates were 10–30 cm kyr −1 on the slopes and 45–60 cm kyr −1 within the basins, while for the post-late glacial sediments (18 kyr B.P.-today) the calculated maximum accumulation rates were 30 cm kyr −1 within the basins and 6–14 cm kyr −1 within the basin margins of North and South Ikarian Basins. A pronounced compressional phase during the Middle-Early Quaternary within the North and South Ikarian Basin can be recognised. Within the N. Ikarian Basin indications of Quaternary strike-slip deformations appeared to be related with en echelon of transpressional reverse faults. From the Middle Quaternary onward continuous subsidence and the reduction in size of subaerial regions are attributed to extension tectonics.