Paleoenvironmental reconstruction of Late Quaternary succession by foraminiferal assemblages of three cores from the San Benedetto del Tronto coast (central Adriatic Sea, Italy)

Abstract

New shelf records based on benthic foraminiferal assemblages allowed reconstruction of the paleoenvironmental evolution of the central Adriatic Sea during the Late Quaternary. Four distinct assemblages related to four different environments were identified based on multivariate analyses (cluster analysis and principal component analysis): circalittoral, shallow water with vegetation, deltaic and shallow marine with riverine influence. Two main phases were recognized by comparing the study area with the northern and southern portion of the Adriatic basin. The first phase was characterized by the last glacial lowstand or the beginning of the last Pleistocene transgression. The foraminiferal assemblage distribution was controlled by sea-level changes and by the location of the ancient Po River delta likely placed at the northern margin of the Mid-Adriatic Deep. A subsequent deepening from a deltaic to normal marine shallow water environment occurred. River supply decreases consistently from the bottom to the top of the cores due to the northern migration of the Po delta. The second phase, which occurred during the Holocene, was characterized by sea-level stabilization and modern water circulation pattern; circalittoral foraminiferal assemblage typical of the outer mud-belt developed during this second phase.