The deep magmatic system of the Campi Flegrei caldera (Italy)

Abstract

[1] Melt inclusions in phenocrysts of the Minopoli2 shoshonite and Fondo Riccio latite eruptive products (Campi Flegrei caldera; 10.2 to 9.5 ka BP) constrain the nature of deep Phlegraean magmatic fluids, their role in volcanism and give new insights into the magmatic plumbing system. The analyzed melt inclusions show that CO 2 is an abundant gaseous species, confirming the results of geochemical studies on the magmatic gas fraction involved in present-day fumarolic emissions. Volatile concentrations within the melt inclusions require gas-melt equilibria between 8 and 9 km depth, and closed-system degassing in presence of ascending CO 2 -rich fluids of deep provenance. Magmas later re-equilibrate at depths up to 3-2 km, i.e. above the top of the carbonate basement. These observations correlate well with independent geophysical and geochemical evidence and are useful constraints for volcanic hazards assessment at Campi Flegrei. Citation: Mangiacapra, A., R. Moretti, M. Rutherford, L. Civetta, G. Orsi, and P. Papale (2008), The deep magmatic system of the Campi Flegrei caldera (Italy), Geophys.

Crystal fractionation, magma step ascent, and syn-eruptive mingling: the Averno 2 eruption (Phlegraean Fields, Italy)

“…More recently, seismic discontinuities detected at depths of 2.7 and 7.5 km were ascribed to the presence of a gas-bearing fractured rock layer overlying a low velocity zone with ponded partial melts (Zollo et al 2008). The development of a mid-crustal sill-like magma reservoir, as hypothesized from seismic reflection profiles, is consistent with the magma crystallization pressure (*200 MPa) derived from petrological data on the Minopoli 2 eruption (10.2 ka; Mangiacapra et al 2008) and the 39 ka year-old CI trachytic magma (Marianelli et al 2006). It has been suggested ) that smaller, possibly shallower magma pockets fed the eruptions that took place in the PFc system over the past 12 ka.…”

Geochemical and isotopic insights into the assembly, evolution and disruption of a magmatic plumbing system before and after a cataclysmic caldera-collapse eruption at Ischia volcano (Italy)

“…This depth range is in line with both estimates of major storage regions within the Ischia magmatic plumbing system based on geophysical modeling Paoletti et al 2009;, and recent MI data (Sbrana et al 2009;Moretti et al 2013). It also corresponds to the depths of magmas feeding the adjacent Campi Flegrei caldera (e.g., Mangiacapra et al 2008;Arienzo et al 2010, and references therein).…”

Bubbles matter: An assessment of the contribution of vapor bubbles to melt inclusion volatile budgets

“…When only bubble-bearing MI were available for study, some workers have acknowledged potential contributions from the bubble by stating that the CO 2 contents and pressures determined from the MI are minimum values (Anderson and Brown, 1993;Cervantes and Wallace, 2003;Spilliaert et al, 2006;Kamenetsky et al, 2007;Johnson et al, 2008;Vigouroux et al, 2008;Ruscitto et al, 2010;Esposito et al, 2011). Others report that bubbles are present, but do not further discuss their potential contribution to MI volatile abundances (Lowenstern, 1994;Roggensack et al, 1997;Walker, 2003;Liu et al, 2006;Mangiacapra et al, 2008;Lloyd et al, 2013). Schipper et al (2010) argue that, based on a positive correlation between CO 2 , H 2 O, and MgO in their highFe MI, the bubbles in these MI were likely either trapped heterogeneously or only contain a vacuum and should be ignored in either case.…”