Extensional tectonics in the Campania Volcanic Zone (eastern Tyrrhenian Sea, Italy): new insights into the relationship between faulting and ignimbrite eruptions

Maurizio Maria Torrente(*) (**), Alfonsa Milia(***), Francesca Bellucci(****) & Giuseppe Rolandi(****)
(*) DSGA, University of Sannio, Via Portarsa, 11 - I-82100 Benevento, Italy. (**) Corresponding author: E-mail address: torrente@ unisannio.it (***) IAMC, CNR, Calata Porta di Massa, Porto di Napoli -I-80133, Naples, Italy. (****) DST, University Federico II, Via Mezzocannone, 8 - I-80138,Naples, Italy.

The Campania Volcanic Zone (CVZ), located on the eastern margin of the Tyrrhenian Sea, is a region characterized by active tectonics and large ignimbrite eruptions starting from 290 ka. A reconstruction of the three-dimensional architecture of the ignimbrite deposits and faults of the CVZ (Campania Plain and Bay of Naples) was made by means of the interpretation of an integrated geological geophysical database. This reconstruction, based on several geological sections combined into two fence diagrams and isopach maps showing the distribution of ignimbrites, reveals: (i) a regional fault pattern characterized by NE-SW, NNE-SSW, NW-SE and E-W structures active over the last 290 ka during ignimbrite eruptions; (ii) a location of the ignimbrite vents over the whole CVZ in correspondence to NE-SW and NW-SE faults; (iii) volcano-tectonic subsidence along normal separation faults that produced asymmetric basins. Furthermore, we have established the tectonic evolution of the CVZ from the emplacement of the ignimbrite deposits, and infer the presence of a WNW-ESE trending extension associated with NNE-SSW normal faults, E-W transfer faults and the reactivation, as transtensional faults, of the NE-SW and the NW-SE structures. The results of this study conflict with the occurrence of a caldera at Campi Flegrei and Naples Bay.

Extensional tectonics, Fault reactivation, Ignimbrite architecture, Pleistocene.