Transparent layers in seismic reflection records from the central Ionian Sea (Mediterranean)-evidence for repeated catastrophic turbidite sedimentation during the Quaternary

Echosounding and SCS records from the Ionian and Sirte Abyssal Plains show, below the Holocene Augias megaturbidite, two additional thick transparent layers which by analogy are interpreted as turbidites. Estimated thicknesses are 10 and 35 m (upper and lower) as a minimum (no consideration of presumable variations of acoustic velocities). The resulting sediment volumes are about 26 and about 200 km3, respectively. Both layers occupy the entire abyssal plain basins similar to the Holocene Augias megaturbidite. A provenance of mobilized sediments from the Gulf of Sirte into the basins is assumed. The ages of the two turbidites have been estimated at 235,000 and 650,000 years, respectively. It is speculated that mobilization was triggered by tsunamis related to volcanic events or earthquakes in the southern Aegean region.