Late Quaternary paleoenvironmental reconstruction of the Tremiti structural high (Central Adriatic Sea) from benthic foraminiferal assemblages

Abstract

Foraminiferal analyses carried out on the VTR01/8 core (Tremiti Islands, Adriatic Sea) lead to the reconstruction of the paleoenvironmental evolution of the area. Although the core site is located at about 1000 km from the Po delta, this study shows that the installation of the recent sedimentological and run-off system (with a shore parallel clay-belt) is similar to that described at sites much closer to the Po delta. The statistical analysis singled out four associations that correspond to four distinct environments. The ecological preferences of the most abundant taxa that characterize each environment reveal that from the bottom of the core to − 50 cm, there is a slight increase of the water depth after which the water depth increases until the present level. Association A (that comprises subclusters A1, A2 and A3) is characterized by shallow-water taxa (e.g., Ammonia beccarii, Quinqueloculina spp. and Elphidium granosum) showing that in the past an infralittoral environment typified the Tremiti High. The subclusters of Association A show that during the deposition of the lower part of the core there had been an alternation of phases characterized by different degrees of riverine influence: the site was at first under the influence of river outflow (A2) that later bypassed the core site (A3) and then came back, although located further away than before (A1). With the rising of the sea level, the Tremiti High became only marginally affected by river influence because the core site is located at a considerable distance from the Po outlets and seaward with respect to the center of the modern mud-belt. As a matter of fact, association B ( Bulimina marginata, Cassidulina carinata and Textularia spp.), which starts at − 46 cm, shows the typical characteristics of the modern mud-belt outer-shelf assemblage, although the presence of opportunistic species is limited by the distant position with respect to the Po delta.