Stratigraphic and structural setting of the Ischia volcanic complex (Naples Bay, Southern Italy) revealed by submarine seismic reflection data

Abstract

High-resolution seismic reflection profiles (Sparker Multitip) offshore southern Ischia Island (Naples Bay) are presented, together with a geological interpretation of their volcanic, structural and sedimentary features. In this frame, new seismo-stratigraphic evidences on buried volcanic structures and overlying Quaternary deposits of the southeastern offshore of the Ischia Island are discussed to highlight their implications on the marine geophysics and volcanology. The Ischia Bank is a large and flat relic volcanic edifice with steep slopes, merging on the continental shelf. The age of this monogenic volcano is unknown, lacking a direct datation of its basement. It represents the eruptive center of the pyroclastic fall cropping out onshore in the eastern sectors of the island, ranging in age from 8 to 6 ky bp. In the eastern Ischia offshore relic volcanic edifices, mostly formed by hialoclastites, have been investigated through high-resolution seismics. They represent remnants of hydro-magmatic volcanic vents and suggest a subaqueous emplacement. Regional seismic sections in the southeastern Ischia offshore, across buried volcanic structures, are finally presented and discussed.