Northeastern Ionian Sea: Palaeoceanographic variability over the last 22 ka

The sediments of a deep sea core (Z1) taken from the north-eastern part of the Ionian Sea near Corfu Island (Greece) was studied in order to reconstruct the palaeoenvironmental history of the basin over the time interval between 22 and 1.5 ka.The downcore variation in the associations of planktonic foraminifera provides a continuous record of the faunal changes over this period. A succession of eight (8) main biozones, based on the major changes in the planktonic foraminifera record, were recognized. Their comparisons with records from the Tyrrhenian and the Adriatic Seas have shown that there is a similarity and synchroneity in the zonation. Furthermore, the downcore compositional changes of the planktonic foraminiferal assemblages and the δ18Ο signal made possible allowed the recognition of millennial to centennial climatic instabilities. These climatic instabilities are associated with the Heinrich 1 (H1) event, the GI-1a to GI-1e INTIMATE events, the Younger Dryas and the Holocene cool events at 8.2 ka, 7 ka, 5 ka, 4 ka and 3 ka. R-mode factor analysis applied to the percentage abundance of plantkonic foraminifera species from seven cores in the Ionian, Adriatic and Tyrrhenian Seas showed that the faunal composition in the three seas was controlled by temporal and spatial variations in: (i) the sea surface temperature, (ii) the stratification and mixing of the surficial waters and (iii) the fertility of surface waters associated with upwelling and/or river inputs. These variations were in phase or out of phase in the three seas.