The TEA C6 record: a reference archive from the Gulf of Taranto (Ionian Sea) for the last 15 ka

An integrated stratigraphic analysis was carried out on the TEA C6 gravity core raised from the Amendolara basin in the Gulf of Taranto. The 4.5 m long succession was investigated by means of sedimentology and textural analysis, petrophysics, micropaleontology and geochemistry with a refined dating framework provided by oxygen isotope, tephrochronology and 14C AMS ages. Textural and micropaleontological data were analysed by means of Compositional data analysis. The results pointed to a deep marine record with no or little disturbance and they aimed to contribute to the reconstruction of the palaeoceanographical and paleoclimatic changes occurred in this sector of the Central Mediterranean during the last 15 ka BP. In particular, data obtained along the sapropelitic interval corresponding to the Sapropel S1 deposition (9.6-7.5 ka BP), offered a detailed insight on the conditions that characterised the study area during this phase. The deposit was sampled with a continuous step of 1 cm-slides of sediment and this allowed to have resolution even in the order of 50 years. During the early Holocene, before the onset of Sapropel deposition, foraminifera show evidence of several centuries characterised by persistence of winter mixing and likely summer eutrophication. The weakening of winter mixing is simultaneous with a change in bottom conditions, leading to the dominance of oxygen resistant species and then to the establishment of anoxic conditions. During this phase, truly onoxic conditions alternate with periods of partial recovery of benthic faunas, the longest of which correspond to the Sapropel S1 interruption. This moment is time fixed by the occurrence of a tephra layer interbedded within the marine deposit. The end of the Sapropel S1 phase coincides with the re-establishment of winter mixing, although eutrophication persists during a transition interval 400 years long. Dynamics and duration of Sapropel S1 in the Gulf of Taranto show similarities with those of the Adriatic Sea. Sea Surface Temperatures (SST) recontructions obtained from planktonic foraminifera by means of CoDaMAT indicate during the stadial GS1 (Younger Dryas) summer and winter SST about 12°C and 7°C lower than present, respectively, and Holocene SST fluctuations in the range of 2°C. According to the results, TEA C6 core might represent a reference archive for the Gulf of Taranto in terms of response of the sedimentary environment to palaeoceanographical and paleoclimatic changes from the late glacial to the late Holocene.