Late Quaternary environmental evolution of the intermontane Valle Caudina basin, southern Italy

The Valle Caudina intermontane basin in the southern Apennines (Italy) lies between the Mt. Taburno on the North and the Avella–Partenio mountains on the South. An analysis of its present-day landscape, and of its stratigraphic and geoarcheological features, has been carried out to reconstruct the Late Quaternary evolution of the basin, filled by alluvial, colluvial and volcaniclastic deposits. The depositional pattern and geomorphological context allow to recognize lacustrine and fluvial–lacustrine sediments, interbedded with ignimbritic layers originating from the Phlegrean Fields and with a Vesuvius pumice level, that represent significant chronological markers. The two lacustrine episodes are connected with volcanic events radiometrically dated (De Vivo et al., 2001). The older predates the Campanian Ignimbrite deposit (~39 kyr BP), while the younger deposited before 5 kyr BP, as indicated by the recovery of Neolithic artifacts. The presence of Roman ruins in the center of the valley suggests that the lake has suffered a substantial downsizing or has disappeared between 5 kyr BP and the Roman Age. A clayey deposit testifies a first lacustrine phase, which has affected the whole plain. Above this unit, heterogeneous deposits indicate the end of the lacustrine phase and the beginning of a clear fluvial sedimentation. Volcaniclastic deposits from the erosion of the Campanian Ignimbrite follow. They are overlapped by a widespread second lacustrine unit. Finally, a reworked and altered volcaniclastic level closes the stratigraphic sequence, while particularly fertile topsoil covered all the plain.