D’Argenio, B.

In this paper we present a correlation between volcanic structures and magnetic anomalies in the Gulf of Naples (Southern Tyrrhenian Sea) based on high resolution magnetic profiling. A densely spaced grid of magnetic profiles coupled with multichannel seismics (seismic source Watergun 15 cubic inch) was recorded in the Gulf of Naples, representing an active volcanic area during the Late Quaternary (volcanic centers of Somma-Vesuvius, Phlegraean Fields and Ischia and Procida islands). The dataset was collected during the oceanographic cruise GMS00-05 which took place during October-November 2000 in the South Tyrrhenian Sea onboard of the R/V Urania (National Research Council, Italy). Shallow volcanic structures in the subsurface of the gulf were recognized by seismo-stratigraphic analysis of high resolution profiles; the volcanic nature of some of these structures was inferred identifying the magnetic anomalies on a high resolution magnetic anomaly map of the gulf. Even if qualitative, the correlations between seismic and magnetic profiles allow us to better assess the geological structure of the Gulf of Naples.

Records of geomagnetic secular variation have been obtained from three cores recovered from the Salerno Gulf (southern Italy). High-resolution petrophysical and palaeomagnetic measurements enabled the reconstruction of a composite curve of geomagnetic palaeosecular variation (PSV), which is compared with the reconstructed PSV curve from Britain and with the French archaeomagnetic data of the last 2.1 ka. The good agreement of the Salerno Gulf record with the above data confirms that our PSV record reaches back for some 9.0ka. In addition to a thick pumice layer originated during the Somma-Vesuvius eruption at 79, two other tephra layers were recognized, at about 1.3 and 3.0 ka BP, that are probably also of Vesuvian origin. The comparison provides an initial chronological framework for assessing the increasing trend of sedimentation rate and its significant changes at about 2.7 ka and 7.0 ka BP. This variation in the deposition rate suggests a link with climatic changes recognized in the Mediterranean region.