Sources and dispersion of recent sediments of the Adriatic Sea

Abstract

The shelf of the Adriatic basin is mostly covered by regressive relict sands deposited by the Pleistocene Po during low stands of sea level of the post-Monastirian regression-Würm Glaciation. Modern deposition over the shelf is limited to mud and sandy mud zones off the Po delta, to a nearshore strip of fine sand and to an offshore belt of mud sediments. The shelf sands belong to the Padane heavy mineral province between the Po delta and the shelf edge off Pescara, and to the Venetian province forming a broad band facing Venice. The principal source of the Padane sediments is the Po basin, which supplies unstable heavy mineral suites derived from igneous and metamorphic rocks of the central and western parts of the Alpine chain. Components belonging to the Venetian province are supplied by the Adige and the other Venetian rivers draining volcanic rocks of the Eastern Alps. In the central and southern Adriatic, mud deposition is predominant. Only an elongate zone is covered by Pleistocene sands redistributed in deeper water by displacement and reworked by wave motion. These bathyal sands belong to the southern-augite province. The principal source is to be ascribed to the volcanic Ofanto-Vulture Basin of the southern Apennine and to the Pleistocene-Holocene volcanic ash of the Vulture, Vesuvius, and the other volcanoes of central and southern Italy. The Dinaric chain in central Albania is the main source of the Albanese province. The heavy minerals of the Adriatic sediments reflect the composition of the source areas. Modification of the mineralogical composition is restricted to Pleistocene and Early Holocene weathering of relatively unstable minerals. Vector analysis of heavy mineral data has established more clearly a mainly longitudinal dispersal pattern on the Adriatic shelf and a transversal one in the central and southern portions of the basin.