Recent Geological Evolution of the Adriatic Sea

Abstract

Analysis of the recent geological development of the Adriatic, from the Po Delta to the Gargano promontory, is based on Quaternary sections that can be correlated with those on land. F~r ~xamp~e, the Sabbi~ di Asti Formation extends offshore from the Po Valley into th~ ~dnatlc Ba.sm .to the re~lOn immediately east of Ancona. Southward, the equivalent umt IS the Sabble dl Car"assar Formation, composed of basinal turbidites. In the southwestern part of th~ Adriatic, the Argille del Santerno Formation is widespread; this formation accumulated m platfor~ to slope and basinal environments. Pleistocene biostratigraphy is ?ase~ on both planktol1Ic and benthonic foraminifera, and we chose Hyalinca balthica to Identify the Neogene-Quaternary boundary. Three seisn:ic-strati~raphi~units are identified, namely a lower unit with even parallel reflectors, an mtermedmte WIth oblique reflectors, and an upper with even parallel renectors. ~he charact~ristics of the intermediate unit are associated with glacially controlled eustatlsm. Apen~me, Yugosl~vian,and probable Po Plain supplying areas are recognized, based on the mam progradatIonal trends. The sediments of the lower unit and the most distal p~rts.of the intermediate fore set unit consist of turbidites that tend to fill the basin by a combma~lOn of out- and ~p-buildingprocesses. The final filling phase in the deepest parts of the basm occurred mamly by up-building. As a reSUlt, turbidites are in contact with sandy-clayey shelf sediments without evidence of slope deposits. The structure of Quaternary sections renects the effects of the underlying strata. This is partly due to draping of deposits over preexisting structures, but also records the continuation of orogenic phases during sedimentation.