Quaternary continental shelf basins of Saronikos Gulf, Aegean Sea

Abstract

The Saronikos Gulf hosts the northwestern end of the South Aegean Active Volcanic Arc. It is affected by extensional back-arc tectonism in a prominent N-S direction, while older E-W rifting is also manifested. Recently acquired swath bathymetry and high-resolution seismic profiles led to the precise morphological mapping of five Quaternary continental shelf basins, along with their neotectonic delineations and their cross-correlation to the onshore active fault zones. Aegina and Methana basins, in the southeast Saronikos Gulf, display subsidence along ENE-WSW and NW-SE axes, and continuous marine sedimentation throughout the Upper Quaternary. Salamina basin in the northeast Saronikos Gulf is a shallow, relatively stable sedimentary basin, intermittently connected to the SE and NW Saronikos Gulf through the Aegina-Fleves and the Aegina-Salamina plateau respectively. In the western and most active region of Saronikos Gulf, the onshore E-W–trending faults of Kechrees and Agios Vassileios extend eastwards until the Salamina-Aegina plateau. The Megara basin is WNW-ESE oriented, possibly affected by the N-S Korfos fault valley, which connects the Megara and Epidavros basins. E-W–trending faults tilt the Quaternary sedimentary blocks, in compatibility to the N-S extensional tectonic regime of the adjacent Gulf of Corinth. Prograding clinoforms in the Megara and Epidavros basins reveal an Upper Quaternary-age intermittent connection to the open sea. Mass transport deposits and volcanic flows in-between the Upper Quaternary sediments of the Epidavros basin manifest the 500–400 ka tectonic phase that affected both the NE Peloponnese coast and the active N-S and NW-SE to WNW-ESE striking faults of the Epidavros basin margin.