The Late Pleistocene to Holocene tephra record of ND14Q site (southern Adriatic Sea). Traceability and preservation of Neapolitan explosive products in the marine realm

A tephrochronological investigation was carried out at site ND14Q (1013 m of water depth), located in the southern Adriatic Sea, offshore the Gargano promontory. It was drilled in the frame of The NextData Project (www.nextdataproject.it, 2011-2013), focused on paleoclimate research. To obtain a composite and well preserved deep marine record, three cores were raised at the study site. Twelve primary cryptotephra and one tephra were analysed in terms of major-element content and correlated with a total of sixteen eruptive events. The studied materials display K-alkaline and subalkaline features pointing to a correlation with the Somma-Vesuvius, Campi Flegrei and Lipari Island (Aeolian Arc) volcanic activity occurred during the Late Pleistocene-Holocene. In detail, major marker tephra of the central Mediterranean have been recognized, among which the Phlegraean Neapolitan Yellow Tuff (ca. 15 ka), Pomici Principali (ca. 12 ka BP) and Astroni-Agnano-Monte Spina (ca. 4.2 ka - 4.4 ka BP) eruptions and, for the first time in this area, the Vesuvian 79 CE event. The very well preserved Mercato (ca. 9 ka BP) and Fiumebianco-Gabellotto (ca. 8.4 ka BP) cryptotephra have also been found in the sapropel S1 interval of the succession, which definitely records the last ca. 22 kyr (Pomici di Base tephra). A number of other Plinian and sub-Plinian events also occur and the availability of multiple cores provided new insights into their temporal relation such as between AP2 and Astroni 6 eruptions. The identification of tephra sourced by well-dated volcanic events, along with several AMS 14C age results, allowed an accurate chronological framework for the composite tephrostratigraphic record, thus providing accurate ages for those deposits with an uncertain correlative event. In addition, stratigraphic evidences in the core replicates at ND14Q site showed that several intervening factors affect preservation and traceability of cryptotephra deposits in the marine realm posing main critical issues on volcanological and paleoclimate research.