La trasgressione versiliana nella Piana del Sarno (Campania)

The Flandrian transgression on the Sarno River Plain (Southern Italy)

Abstract

By means of geomorphological investigations, drilling data analysis and some radiocarbon datings, the subsurface extent and nature of Olocene deposits of the Sarno River Plain was clearified. The informations obtained allow to reconstruct the sedimentary and geomorphological dynamics of the Versilian (Flandrian) transgression on this area of active volcanism (it lies at the base of Vesuvius volcano). During the first three millennia of Holocene the rising sea level invaded the lower part of the plain without performing much lateral planation. Probably during the fourth and fifth millennium the trasgressive gulf went broadened through abrasion of platforms, mostly cut into Late Pleistocene alluvial fans. Sand platform is to be found at – 20 to – 13 m of altitude. Possibly around 6 000 years ago the coastline inverted its tendency and started prograding notwithstanding the fact that the area was still subsiding with rate of about 2 mm/yr. Beach deposits having an age of 5 600 to 4 500 yrs BP are presently found at 3.5 to 10 m below the present s.l. whereas the zero level of the Roman Age beach is lowered at – 4 / – 5 meters below the present one. Minor trasgressions and pauses interrupted the progradation of the coast. One of those occurred some 3 600 yrs BP and another one some 950 yrs BP.