Multiproxy study of cores from the Garigliano Plain: An insight into the Late Quaternary coastal evolution of Central-Southern Italy

Two boreholes, both about 16 m-deep, have been drilled in the Garigliano Plain, a coastal-alluvial plain located at the boundary between southern Latium and northern Campania, Italy. The drill holes have been planned and carried out in the southern part of the plain, near to the bordering ridge of Mount Massico. The multidisciplinary analyses performed on sediment samples from both cores revealed the presence of several marine and continental sedimentation environments, transitional facies and volcanic rocks. All these data, together with the stratigraphic correlation between the two logs, allowed the reconstruction of the sedimentary and morphological evolution of the plain during the Late Quaternary. Further, such an evolutionary sequence has been used as a comparison scheme with regard to other coastal plains of the Tyrrhenian side of central and southern Italy to stress similar or different behaviours among them on a distance of about 400 km of coastal belt. Some remarkable differences have been actually enlighten, with particular reference to the MIS 5.5 and the Holocene. The occurrence in both cores of products of the Campanian Ignimbrite - a ~ 40 ka pyroclastic unit - and associated reworked deposits (about five metres-thick in both cases), has been here reported for the first time in the subsurface of the southern part of the Garigliano Plain. In addition, a tephra layer has been detected at -14.50 m of depth (i.e. 13.50 m a.s.l.) in the northernmost core. This layer has been 40Ar/39Ar dated at 124.5 ± 0.5 ka. In the upper part of the same drill core, deposits interpreted as lagoonal-swamp facies have been recognized. On the basis of 14C dating, we can attribute the starting stage of such a sedimentation to the effects induced by the Post-glacial sea-level rise at about 8000 yr BP. These chronological constraints permitted us to obtain from the paleoecological, palynological, and granulometric analyses of the sampled successions helpful and precise information about sea-level changes along that coastal belt.