40Ar/39Ar dating of tuff vents in the Campi Flegrei caldera (southern Italy): toward a new chronostratigraphic reconstruction of the Holocene volcanic activity

Abstract

Abstract. The Campi Flegrei hosts numerous monogenetic vents inferred to be younger than the 15 ka Neapolitan Yellow Tuff. Sanidine crystals from the three young Campi Flegrei vents of Fondi di Baia, Bacoli and Nisida were dated using 40Ar/39Ar geochronology. These vents, together with several other young edifices, occur roughly along the inner border of the Campi Flegrei caldera, suggesting that the volcanic conduits are controlled by caldera-bounding faults. Plateau ages of ∼9.6 ka (Fondi di Baia), ∼8.6 ka (Bacoli) and ∼3.9 ka (Nisida) indicate eruptive activity during intervals previously interpreted as quiescent. A critical revision, involving calendar age correction of literature 14C data and available 40Ar/39Ar age data, is presented. A new reference chronostratigraphic framework for Holocene Phlegrean activity, which significantly differs from the previously adopted ones, is proposed. This has important implications for understanding the Campi Flegrei eruptive history and, ultimately, for the evaluation of related volcanic risk and hazard, for which the inferred history of its recent activity is generally taken into account

Comment on “40Ar/39Ar dating of tuff vents in the Campi Flegrei caldera (southern Italy): toward a new chronostratigraphic reconstruction of the Holocene volcanic activity” by Fedele et al. [Bull Volcanol; 73:1323–1336]

“…This robust up-to-date chronology was constrained using Bayesian analysis (OxCal) of all published 14 C data, 40 Ar/ 39 Ar ages, and the stratigraphic relationships. This chronological framework disagrees with that of Fedele et al (2011).…”

“…They produced data for the some of the same units that Fedele et al (2011) dated. Di Renzo et al (2010 dated single crystals using the total fusion method (SCTF) and Fedele et al (2011) Renzo et al 2010). The discrepancies are most likely due to xenocrystic contamination.…”

“…In particular, the authors propose to amend the previously established Holocene chronostratigraphy of volcanic activity of Campi Flegrei caldera, presented in Di , Orsi et al (2004), Isaia et al (2009). The proposed changes of Fedele et al (2011) are based on new geochronologic data, a calibration of already existing 14 C ages, and a stratigraphic survey (Perrotta et al 2010). However, the new chronological data are limited and pre-existing stratigraphic studies have not been considered, and this yields an eruption chronology that is inconsistent with the actual stratigraphic framework.…”

“…The volcanic history is important for hazard assessment, thus the scientific community must validate the strength of conclusions. Fedele et al (2011) propose a new reference chronostratigraphic framework for Holocene Phlegrean activity, and discuss the implications for the Campi Flegrei (CF) volcanic history and related volcanic hazards. In particular, the authors propose to amend the previously established Holocene chronostratigraphy of volcanic activity of Campi Flegrei caldera, presented in Di , Orsi et al (2004), Isaia et al (2009).…”

The Neapolitan Yellow Tuff caldera offshore the Campi Flegrei: Stratal architecture and kinematic reconstruction during the last 15ky

“…1) Rosi and Sbrana, 1987;Barberi et al, 1991;Scandone et al, 1991;Scarpati et al, 1993;Wohletz et al, 1995;Orsi et al, 1996;Florio et al, 1999;Judenherc and Zollo, 2004 Following the NYT eruption, the evolution of the Campi Flegrei was dominated by hydromagmatic activity with occasional plinian phases and minor effusive activity forming lava domes . Several tens of monogenic phreato-magmatic vents including tuff rings, tuff cones, cinder and spatter cones, have been active in the last 15 kyr mostly inside the NYT caldera collapse Di Vito et al, 1999;Insinga et al, 2006;Di Renzo et al, 2011;Fedele et al, 2011). The last event was the Monte Nuovo eruption in 1538 A.D., which occurred after some 100 years of caldera uplift (Parascandola, 1946;Di Vito et al, 1987;Morhange et al, 1999;D'Oriano et al, 2005;Piochi et al, 2005;Bellucci et al, 2006;De Natale et al, 2006).…”