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)

Abstract

. (2014) '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).', Contributions to mineralogy and petrology., 168 (3). p. 1035.Further information on publisher's website:https://doi.org/10.1007/s00410-014-1035-1Publisher's copyright statement:The nal publication is available at Springer via https://doi.org/10.1007/s00410-014-1035-1. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. km depth. The deep-sourced latitic to trachytic magmas stalled at shallow depths (4-6 km depth), differentiated to phonolite through crystal fractionation and assimilation of a feldspar-rich mush, or ascended directly to the surface and erupted.

Isotopic microanalysis sheds light on the magmatic endmembers feeding volcanic eruptions: The Astroni 6 case study (Campi Flegrei, Italy)

“…For instance, the seven Astroni eruptions, which have followed each other in close succession within the same vent area , might have been triggered by mixing events that occurred shortly prior to the onset of activity (Tonarini et al, 2009). Should the fresh magma be hot and gas-rich, it might cause re-melting of a crystal mush, an event that possibly occurred in the past at Ischia (Brown et al, 2014) as well as in other volcanoes (e.g., Burgisser and Bergantz, 2011;Wiesmaier et al, 2012). There are several geophysical lines of evidence suggesting that the most intense, recent unrest event that occurred at Campi Flegrei (1982)(1983)(1984) might have been caused by the emplacement at shallow depth of a small volume of magma, on the order of 0.01 km 3 (e.g., De Siena et al, 2010;Trasatti et al, 2011;Amoruso et al, 2014).…”

“…In order to shed light on the possible origin of this component, we have compared the Sr and Nd isotopic compositions of these diopside crystals and glass, with that measured on minerals from the majority of the Phlegrean Volcanic District products of variable ages. These include mostly clinopyroxene and feldspar from products of Ischia island (75 to b10 ka; D' Antonio et al, 2013;Brown et al, 2014), and from the Campanian Ignimbrite eruption (Arienzo et al, 2009) At Ischia, the past 75 ka activity was characterized by arrival of isotopically distinct magmas in the feeding system (Civetta et al, 1991;Piochi et al, 1999;D'Antonio et al, 2007D'Antonio et al, , 2013Brown et al, 2014), each with its own crystal load: one with lower 87 Sr/ 86 Sr and higher 143 Nd/ 144 Nd ratios (~0.7060 and 0.51256), and another with higher 87 Sr/ 86 Sr and lower 143 Nd/ 144 Nd ratios (~0.7069 and~0.51254). The general Sr-Nd isotopic trend of minerals and glass from Astroni eruptions partially overlaps the field of PVD minerals (Fig.…”

“…Sr and Nd isotopic compositions of the Astroni products partially overlap those of the majority of products extruded in the time window from ca. 75 to 2 ka at Ischia and Campi Flegrei (Arienzo et al, 2009;Tonarini et al, 2009;D'Antonio et al, 2013;Brown et al, 2014). The grey bar represents the whole range of 87 Sr/ 86 Sr of the Astroni clinopyroxene (both diopside and ferroan diopside) crystals, for many of which there is no 143 Nd/ 144 Nd.…”

The crystallization of shoshonitic to peralkaline trachyphonolitic magmas in a H2O–Cl–F-rich environment at Ischia (Italy), with implications for the feeder system of the Campania Plain volcanoes

“…The microcrystalline groundmass is made up of feldspar, clinopyroxene, olivine, magnetite (1980). Other bulk-rock analyses (white symbols) are those of Poli et al (1987), Crisci et al (1989), Piochi et al (1999) and Brown et al (2009Brown et al ( , 2014. 3.…”

“…The Ischian volcanic rocks have the least radiogenic Sr-isotope and the most radiogenic 143 Nd/ 144 Nd ratios among the rocks of the Roman Magmatic Province ( 87 Sr/ 86 Sr = 0.7049-0.7070 and 143 Nd/ 144 Nd = 0.51249-0.51268; e.g., Avanzinelli et al, 2008;Brown et al, 2014;Civetta et al, 1991, and references therein;D'Antonio et al, 1999D'Antonio et al, , 2007D'Antonio et al, , 2013Di Girolamo et al, 1995). Evidence of (minor) changes of Sr-Nd isotope ratios in the different cycles of activity of Ischia volcanic complex is already known (cf.…”