On the occurrence of the Neapolitan Yellow Tuff tephra in the Northern Phlegraean Fields offshore (Eastern Tyrrhenian margin; Italy)

摘要

A main volcanic marker has been identified for the first time on the continental shelf of the northernudPhlegraean Fields in the Gaeta Gulf (Campania region, eastern Tyrrhenian margin, Italy) by meansudof Subbottom Chirp profile grid and stratigraphic analysis of a core collected on the slope. In theudseismic sections, the core bottom corresponds to the top of a continuous and parallel reflector (V)udinterbedded within the transgressive deposits of the Late Quaternary-Holocene depositionaludsequence. The Transgressive System Tract deposits are particularly thick compared to the majorityudof the transgressive deposits of other shelf settings. This might be due to the input of pyroclasticudand volcanoclastic deposits related to the intense eruptive activity of the Campania Plain during theudLate Pleistocene-Holocene time span. Undulations and pockmarks are the main morphologicaludfeatures of the sea floor and they might be linked to gas uprising, widely detected in the study area.udThe V reflector is located on the shelf from northeast to southwest at different depths, ranging fromud10 ms (about 8 m) to 30 ms (about 25 m) below sea floor and it can be mapped down to theudcontinental slope. The geological calibration of this continuous reflector coupled withudtephrostratigraphic analysis, allowed to correlate it with the Neapolitan Yellow Tuff depositsudemplaced at Phlegraean Fields at ca. 15 ka.