Using Tephrochronology and palynology to date the MIS 13 lacustrine sediments of the Mercure basin (Southern Apennines - Italy)

The present paper deals with the chronostratigraphy of the lacustrine infilling of the Mercure basin, an intramontane depression of Southern Apennines, located along the Calabria-Lucania boundary. Tephrochronology and pollen analysis were carried out on the outcropping portion of the infilling succession, exposed along V-shaped tributary valleys of the Mercure river. Lithological and chemical features of the thickest and best preserved tephra layer were fully characterized and the layer was 40Ar/39Ar dated to 514 ± 16 ka. Pollen analyses revealed the occurrence of warm and humid interglacial conditions that were correlated to MIS 13 on the basis of age determination. The chemical composition of glasses made it possible to point out the Sabatini Volcanic District as the most probable source of the investigated tephra layer. Although chemical features would corroborate correlation with the Tufo Giallo della Via Tiberina multiphase eruption, occurred between 561 and 548 ka, the integration of tephrochronology and pollen analysis points to a younger age, falling within MIS 13. On this basis, correlation with one of the four explosive events occurred at the Latial district in the 514-449 time span has been proposed, making the Mercure tephra layer a valid marker for MIS 13 in central -southern Italy.