New constraints on the pyroclastic eruptive history of the Campanian volcanic Plain (Italy)

The similar to 150 km(3) (DRE) trachytic Campanian Ignimbrite, which is sit uated north-west of Naples, Italy, is one of the largest eruptions in the M editerranean region in the last 200 ky. Despite centuries of investigation, the age and eruptive history of the Campanian Ignimbrite is still debated, as is the chronology of other significant volcanic events of the Campanian Plain within the last 200-300ky. New Ar-40/Ar-39 geochronology defines the age of the Campanian Ignimbrite at 39.28 +/-0.11 ka, about 2 ky older than the previous best estimate. Based on the distribution of the Campanian Ign imbrite and associated uppermost proximal lithic and polyclastic breccias, we suggest that the Campanian Ignimbrite magma was emitted from fissures ac tivated along neotectonic Apennine faults rather than from ring fractures d efining a Campi Flegrei caldera. Significantly, new volcanological, geochro nological, and geochemical data distinguish previously unrecognized ignimbr ite deposits in the Campanian Plain, accurately dated between 157 and 205ka . These ages, coupled with a xenocrystic sanidine component > 315 ka, exten d the volcanic history of this region by over 200 ky. Recent work also iden tifies a pyroclastic deposit, dated at 18.0 ka, outside of the topographic Campi Flegrei basin, expanding the spatial distribution of post-Campanian I gnimbrite deposits. These new discoveries emphasize the importance of conti nued investigation of the ages, distribution, volumes, and eruption dynamic s of volcanic events associated with the Campanian Plain. Such information is critical for accurate assessment of the volcanic hazards associated with potentially large-volume explosive eruptions in close proximity to the den sely populated Neapolitan region.