Quaternary Transgressive/Regressive Cycles in the Gulf of Argos, Greece

Borings in the Argive Plain reveal cycles of marine incursions, each ending with a Mediterranean soil profile and followed by a prograded fluvial and coastal wedge. The sediment prism of the Gulf of Argos shelf, visible in high-resolution seismic reflection profiles, also consists of transgressive and regressive depositional sequences identified by onlap, downlap, and truncation of deposits. At least four major reflectors, recognizable by their high acoustic impedance and erosional features, can be correlated across the shelf. The sediments between each pair of reflectors represent the seaward part of a set of transgressive and regressive marine deposits. They can be matched to the stratigraphic sequence on land where each marine unit is topped by a soil. Corrected for subsidence, the terminations of the onlapping and downlapping units define a local sea-level history; its time scale can be derived from a comparison with the eustatic sea-level history deduced from ocean cores. Thus, marine seismic reflection data can be used for the correlation of Quaternary oceanic and terrestrial chronologies.