Magma dynamics during the 2007 Stromboli eruption (Aeolian Islands, Italy): Mineralogical, geochemical and isotopic data P. Landi a, ⁎, R.A. Corsaro b , L. Francalanci c , L. Civetta d,e , L. Miraglia b , M. Pompilio a , R. Tesoro d,e a Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa, Via della Faggiola, 32, I-56126 Pisa, Italy b Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, Piazza Roma, 2, I95125 Catania, Italy c Dipartimento di Scienze della Terra, Università di Firenze, Via La Pira, 4, I-50121 Firenze, Italy d Dipartimento di Scienze Fisiche, Università di Napoli Federico II, Via Cinthia, I-80126 Napoli, Italy e Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli-Osservatorio Vesuviano, Via Diocleziano, 328, I-80124 Napoli, Italy abstract article info Article history: Received 3 June 2008 Accepted 6 November 2008 Available online 28 November 2008 Keywords: Stromboli volcano petrological monitoring steady-state system geochemistry mineralogy Sr-Nd isotopes After the 6 month-long effusive event of 2002-2003, a new lava effusion occurred at Stromboli between 27 February and 2 April 2007. Despite the different durations, approximately the same volume of magma was emitted in both eruptions, in the order of 10 7 m 3 . A paroxysmal eruption occurred at the summit craters in both the 2002–2003 and 2007 episodes, during which a significant amount of low porphyritic (LP), volatile- rich magma was erupted. In both cases, the paroxysm did not interrupt the lava emission. Here, we present compositional data, including texture, mineralogy, chemistry and Sr and Nd isotope ratios of bulk-rock, groundmass and separated minerals of lavas erupted in 2007, together with chemistry and Sr and Nd isotope composition of the pumices emitted during the 15 March paroxysm. As a whole, the lavas have the same texture and chemistry that characterize the highly porphyritic (HP) products usually erupted at Stromboli during normal Strombolian activity and effusive events. Compared to the previous HP products, the 2007 lavas show minor but systematic mineralogical and isotopic variations which are consistent with a modest increase of the magma supply rate of the volcano. Compositional variations during the entire duration of the event are very modest. Glass chemistry changes in lavas erupted in the second half of March can be explained by the minor mixing between the volatile-rich LP magma rising through the shallow magmatic system during the 15 March paroxysm and the degassed residing HP magma. A first conclusion of this study is that there is no compositional evidence supporting major changes in the magma dynamics of the volcano accompanying the effusive activity, as also suggested for the 2002–2003 event. The activity of Stromboli is controlled by a steady state feeding system in which refilling, mixing, degassing and crystallization at shallow level continuously operate, with modest oscillations in the magma supply rate. Switching between normal Strombolian and effusive activity is related to periods of relatively more vigorous refilling of the shallow system, leading to progressive pressure increase in the upper conduits associated with only minor compositional variations in the erupted products. © 2008 Elsevier B.V. All rights reserved. 1. Introduction The renewal of the eruptive vigor in basaltic volcanoes in persistent or quasi-persistent state of activity is commonly associated with changes in chemical and/or textural characteristics of the erupted magmas, both correlated with shallow magma dynamics, changes in geochemical parameters and edifice deformation (Garcia et al., 2000; Thornber, 2003; Corsaro and Pompilio, 2004; Vlastélic et al., 2005). Reactivation or increase in the volcanic activity may also occur without any evident variations in the chemistry of the erupted products. However, a careful analytical investigation often highlights trace element and/or isotopic changes that, even if slight, can be a sign of a relevant modification in the magma dynamics (Landi et al., 2006; Schiavi et al., 2006). Several studies reveal that the magmas feeding these kinds of volcanoes usually show short and long-time composi- tional changes, depending on the structure of the plumbing system, the recharge history of magma reservoir and the interplay between the deeper and the shallow part of the feeding system (Garcia and Wolfe, 1988; Garcia et al., 2000; Thornber, 2003; Corsaro and Pom- pilio, 2004; Vlastelic et al., 2005). Only a prolonged petro-chemical monitoring, with systematic sampling of the erupted products, associated with detailed studies of their texture, chemical and isotopic composition, can reveal chemical trends in time that allow under- standing the behaviour of the magmatic plumbing system and fore- casting its evolution. Stromboli (Fig. 1), Aeolian Islands, Southern Italy, is one of the most active, best-studied and best-monitored volcanoes in the world. Gas geochemistry and geophysical data have been collected nearly con- tinuously by the staff of the Istituto Nazionale di Geofisica e Vulcanologia Journal of Volcanology and Geothermal Research 182 (2009) 255–268 ⁎ Corresponding author. E-mail address: landi@pi.ingv.it (P. Landi). 0377-0273/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.jvolgeores.2008.11.010 Contents lists available at ScienceDirect Journal of Volcanology and Geothermal Research journal homepage: www.elsevier.com/locate/jvolgeores