A high-resolution record of the last deglaciation in the Central Mediterranean Sea: Palaeovegetation and palaeohydrological evolution

A high-resolution palynological and stratigraphical record of a marine deep-sea core in the Adriatic sea documents marine and continental palaeoenvironmental changes in the basin during the last deglaciation and early Holocene. A chronology is derived from the oxygen isotope stratigraphy. Three periods of aridity, marked by the development of a semi-desert rich in Artemisia, occurred between 18.5 and 16 kyr, between 14.4 and 12.7 kyr and between 11.1 and 9.7 kyr, consistent with the Last Glacial Maximum, the Oldest Dryas and the Younger Dryas. They are correlated with increases in productivity and intensification of the Levantine water formation in the Eastern Mediterranean basin. During the warmer Bolling/Allerod (12.7-11.1 kyr), the presence of the cold temperate dinocyst Bitectatodinium tepikiense is interpreted as indicating the establishment of a strong seasonal thermal gradient, probably linked to seasonal cold freshwater runoff from the Po river, attested by the unique presence of pollen of freshwater plants. The expansion of forest and the development of the warmer dinocysts start with Termination IB. During the Holocene, three tree phases are recognized and are contemporaneous with the Preboreal, Boreal and Atlantic chronozones of Europe. The two phases of sapropel deposition are marked by higher pollen and dinocyst concentrations and a high representation of Brigantedinium spp which indicate higher preservation of organic material and/or freshwater runoff of the Po River. (C) 1998 Elsevier Science Ltd. All rights reserved.