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- PublicationRestrictedThe Averno 2 fissure eruption: a recent small-size explosive event at the Campi Flegrei Caldera (Italy)(2011)
; ; ; ; ; ; ; ;Di Vito, M. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Arienzo, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Braia, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Civetta, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;D’Antonio, M.; Università di Napoli ;Di Renzo, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Orsi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ;; ; ; The Averno 2 eruption (3,700 ± 50 a B.P.) was an explosive low-magnitude event characterized by magmatic and phreatomagmatic explosions, generating mainly fall and surge beds, respectively. It occurred in the Western sector of the Campi Flegrei caldera (Campanian Region, South Italy) at the intersection of two active fault systems, oriented NE and NW. The morphologically complex crater area, largely filled by the Averno lake, resulted from vent activation and migration along the NE-trending fault system. The eruption generated a complex sequence of pyroclastic deposits, including pumice fall deposits in the lower portion, and prevailing surge beds in the intermediate-upper portion. The pyroclastic sequence has been studied through stratigraphical, morphostructural and petrological investigations, and sub- divided into three members named A through C. Member A was emplaced during the first phase of the eruption mainly by magmatic explosions which generated columns reaching a maximum height of 10 km. During this phase the eruption reached its climax with a mass discharge rate of 3.2 106 kg/s. Intense fracturing and fault activation favored entry of a significant amount of water into the system, which produced explosions driven by variably efficient water-magma inter- action. These explosions generated wet to dry surge deposits that emplaced Member B and C, respectively. Isopachs and isopleths maps, as well as areal distribution of ballistic fragments and facies variation of surge deposits allow definition of four vents that opened along a NE oriented, 2 km long fissure. The total volume of magma extruded during the eruption has been estimated at about 0.07 km3 (DRE). The erupted products range in composition from initial, weakly peralkaline alkali-trachyte, to last-emplaced alkali-trachyte. Isotopic data and modeling suggest that mixing occurred during the Averno 2 eruption between a more evolved, less radiogenic stored magma, and a less206 18 - PublicationRestrictedMagmatic History of Somma^Vesuvius on the Basis of New Geochemical and Isotopic Data from a Deep Borehole (Camaldoli dellaTorre)(2007)
; ; ; ; ; ; ; ; ; ;Di Renzo, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Di Vito, M. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Arienzo, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Carandente, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Civetta, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;D'Antonio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Giordano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Orsi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Tonarini, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; ; ; ; ; A continuous-coring borehole recently drilled at Camaldoli dellaTorre on the southern slopes of Somma^Vesuvius provides constraints on the volcanic and magmatic history of the Vesuvian volcanic area since c. 126 ka BP. The cored sequence includes volcanic units, defined on stratigraphical, sedimentological, petrological and geochemical grounds, emitted from both local and distal vents. Some of these units are of known age, such as one Phlegraean pre-Campanian Ignimbrite, Campanian Ignimbrite (39 ka), Neapolitan Yellow Tuff (14 9ka) and Vesuvian Plinian deposits, which helps to constrain the relative age of the other units.The main rock types encountered are shoshonite, phonotephrite, latite, trachyte and phonolite. The sequence includes, from the base upwards: a thick succession of pyroclastic units emplaced between 126 and 39 ka, most of them attributed to eruptions that occurred in the Phlegraean area; the Campanian Ignimbrite; the products of a local tuff cone formed between 39 ka and the deposition of the products of the earliest activity of the Mt. Somma volcano; the products of the Somma^Vesuvius volcano, which include from the base upwards a thick sequence of lavas, pyroclastic rocks and the products of a local spattercone dated between 3 7ka and AD 79.The data obtained from the study of the borehole show that, before the Campanian Ignimbrite eruption, low-energy explosive volcanism took place in the Vesuvian area, whereas mostly high-energy explosive eruptions characterized the Campi Flegrei activity. In the Vesuvian area, Campanian Ignimbrite deposition was followed by the eruption of a local tuff cone and a long repose time, which predated the formation of the Mt. Somma edifice. Since 18 3 ka (Pomici di Base eruption) the activity of Somma^Vesuvius became mostly explosive with rare lava effusions.The shallowest cored deposits belong to the Camaldoli dellaTorre cone, formed between the Pomici di Avellino and Pomici di Pompei eruptions (3 7 ka^AD 79). Newgeochemical and Sr^Nd^Pb^ B-isotopic data on samples from the drilled core, together with those available from the literature, allow us to further distinguish the volcanic rocks as a function of both their provenance (i.e. Phlegraean or Vesuvian areas) and age, and to identify different magmatic processes acting through time in the Vesuvian mantle source(s) and during magma ascent towards the surface. Isotopically distinct magmas, rising from a mantle source variably contaminated by slab- derived components, stagnated at mid-crustal depths (8^10 km below sea level) where magmas differentiated and were probably contaminated. Contamination occurred either with Hercynian continental crust, mostly during the oldest stages of Vesuvian activity (from 39 to 16 ka), or with Mesozoic limestone, mostly during recent Vesuvian activity. Energy constrained assimilation and fractional crystallization (EC-AFC) modelling results show that contamina- tion with Hercynian crust probably occurred during differentiation from shoshonite to latite. Contamination with limestone, which is not well constrained with the available data, might have occurred only during the transition from shoshonite to tephrite. From the ‘deep’ reservoir, magmas rose towards a series of shallow reservoirs, in which they differentiated further, mixed, and fed volcanic activity.315 32 - PublicationRestrictedThermal and geochemical constraints on the ‘deep’ magmatic structure of Mt. Vesuvius(2004)
; ; ; ; ; ;Civetta, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;D'Antonio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;de Lorenzo, S.; Dip. Geologia e Geofisica, University of Bari, Bari ;Di Renzo, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Gasparini, P.; Dip. Scienze Fisiche, Università Federico II, Napoli; ; ; ; A review of available and new isotopic data on rocks from Mt. Vesuvius together with geophysical and mineralogical data allow us to define a ‘deep’ complex magmatic reservoir where mantle-derived magmas arrive, stagnate and differentiate, and to constrain a thermal model, which describes the history and present state of the reservoir and its surrounding rocks. The top of the reservoir is located at about 8 km depth, and it extends discontinuously down to 20 km depth. The reservoir is hosted in densely fractured continental crustal rocks, where magmas and crust can interact, and, according to thermal modeling results, has been fed more than once in the last 400 ka. The hypothesis of crustal contamination is favored by the high temperatures reached by crustal rocks as a consequence of repetitive intrusions of magma. From the ‘deep’ reservoir magmas rise to form ‘shallow’ magma chambers at different depths, as already known in the literature, where they can undergo low-pressure differentiation and mixing and feed the volcanic activity.212 67 - PublicationOpen AccessMineral-Melt Equilibria and Geothermobarometry of Campi Flegrei Magmas: Inferences for Magma Storage Conditions(2022)
; ; ; ; ; ; ; ; ; ; ;; ;The eruptions of Campi Flegrei (Southern Italy), one of the most studied and dangerous active volcanic areas of the world, are fed by mildly potassic alkaline magmas, from shoshonite to trachyte and phonotrachyte. Petrological investigations carried out in past decades on Campi Flegrei rocks provide crucial information for understanding differentiation processes in its magmatic system. However, the compositional features of rocks are a palimpsest of many processes acting over timescales of 100–104 years, including crystal entrapment from multiple reservoirs with different magmatic histories. In this work, olivine, clinopyroxene and feldspar crystals from volcanic rocks related to the entire period of Campi Flegrei’s volcanic activity are checked for equilibrium with combined and possibly more rigorous tests than those commonly used in previous works (e.g., Fe–Mg exchange between either olivine or clinopyroxene and melt), with the aim of obtaining more robust geothermobarometric estimations for the magmas these products represent. We applied several combinations of equilibrium tests and geothermometric and geobarometric methods to a suite of rocks and related minerals spanning the period from ~59 ka to 1538 A.D. and compared the obtained results with the inferred magma storage conditions estimated in previous works through different methods. This mineral-chemistry investigation suggests that two prevalent sets of T–P (temperature–pressure) conditions, here referred to as “magmatic environments”, characterized the magma storage over the entire period of Campi Flegrei activity investigated here. These magmatic environments are ascribable to either mafic or differentiated magmas, stationing in deep and shallow reservoirs, respectively, which interacted frequently, mostly during the last 12 ka of activity. In fact, open-system magmatic processes (mixing/mingling, crustal contamination, CO2 flushing) hypothesized to have occurred before several Campi Flegrei eruptions could have removed earlier-grown crystals from their equilibrium melts. Moreover, our new results indicate that, in the case of complex systems such as Campi Flegrei’s, in which different pre-eruptive processes can modify the equilibrium composition of the crystals, one single geothermobarometric method offers little chance to constrain the magma storage conditions. Conversely, combined methods yield more robust results in agreement with estimates obtained in previous independent studies based on both petrological and geophysical methods771 131 - PublicationRestrictedPetrology of lavas from the 2004–2005 flank eruption of Mt. Etna, Italy: inferences on the dynamics of magma in the shallow plumbing system(2009)
; ; ; ;Corsaro, R. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Civetta, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Di Renzo, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; Following the 2001 and 2002–2003 flank eruptions, activity resumed at Mt. Etna on 7 September 2004 and lasted for about 6 months. This paper presents new petrographic, major and trace element, and Sr–Nd isotope data from sequential samples collected during the entire 2004–2005 eruption. The progressive change of lava composition allowed defining three phases that correspond to different processes controlling magma dynamics inside the central volcano conduits. The compositional variability of products erupted up to 24 September is well reproduced by a fractional crystallization model that involves magma already stored at shallow depth since the 2002–2003 eruption. The progressive mixing of this magma with a distinct new one rising within the central conduits is clearly revealed by the composition of the products erupted from 24 September to 15 October. After 15 October, the contribution from the new magma gradually becomes predominant, and the efficiency of the mixing process ensures the emission of homogeneous products up to the end of the eruption. Our results give insights into the complex conditions of magma storage and evolution in the shallow plumbing system of Mt. Etna during a flank eruption. Furthermore, they confirm that the 2004–2005 activity at Etna was triggered by regional movements of the eastern flank of the volcano. They caused the opening of a complex fracture zone extending ESE which drained a magma stored at shallow depth since the 2002–2003 eruption. This process favored the ascent of a different magma in the central conduits, which began to be erupted on 24 September without any significant change in eruptive style, deformation, and seismicity until the end of eruption.157 32 - PublicationRestrictedPetrology of Late Jurassic-Early Cretaceous ophiolites from Timpa delle Murge (Southern Apennines, Italy): insights from fragments of Tethyan oceanic crust(2008)
; ; ; ; ; ; ; ; ; ; ; On the Timpa delle Murge hill, located in the Lucania region close to Mt. Pollino (southern Apennines, Italy), Upper Jurassic – Lower Cretaceous metaigneous and metasedimentary rocks crop out, which are believed to represent fragments of Tethys oceanic crust obducted on continental crust during the Apennine orogenic phases. This ophiolitic sequenceincludes, from base upward: gabbros, pillow lavas, pillow breccias, and a pelagic sedimentary pile made up of radiolarian cherts, red and green shales, quartz-arenites and black shales. A few kilometers apart, the Episcopia - S. Severino Mélange includes serpentinized peridotites, likely representing fragments of an upper mantle portion. The radiolarian cherts were dated at 161 Ma based on their microfossil content, and this age is believed to be the end of oceanic crust generation in that area. Both serpentinites and the whole oceanic crust sequence were affected by subduction-related HP/LT metamorphism, marking a burying and exhumation episode occurred during the Late Oligocene-Early Miocene Apennine orogenesis. Only few literature data are available on the petrology of these rocks, thus a modern petrologic investigation is needed in order to better characterize this ophiolitic sequence, and shed light on the nature and history of this part of the Tethyan oceanic crust. In this contribution, major oxide and trace element geochemistry data will be illustrated forrepresentative shales and wackes from the Timpa delle Murge and Crete Nere formations. Geochemical modeling using compositional data of these metasedimentary rocks will be presented in order to find a possible link between the oceanic crust which was subducted during the Tethys closure, and subduction-related Tertiary-Quaternary volcanism of southern Italy.114 2 - PublicationRestrictedMineralogical, geochemical and isotopic characteristics of alkaline mafic igneous rocks from Punta delle Pietre Nere (Gargano, Southern Italy)The Punta delle Pietre Nere (Gargano, Southern Italy) igneous body is constituted by gabbroic and syenitic rocks with lamprophyric affinity of different age (58 and 62 Ma, respectively). The chemical composition of the minerals clearly indicates that there is no genetic relationship between the two lithotypes, in agreement with their significant age difference. The chemical (trace elements) and Sr-Nd-Pb-isotopic composition of these rocks highlights an “anorogenic” geochemical affinity derived from mixed DMM-HIMU-EM mantle reservoirs, similarly to other Paleogene-Oligocenemagmatic provinces in the Circum-Mediterranean Area. In past literature, these features were interpreted as evidences for enriched asthenospheric mantle plume upwelling from deep regions beneath the Western Europe. Here we suggest that the HIMU-like composition of Punta delle Pietre Nere rocks is related to a lithosphericmantle source bearing amphibole-rich veins, resulting from crystallization of melts within the amphibole stability field in presence of H2O, as shown by several experimental works. Our results suggests partial melting at 70–90 km depth, which corresponds to the spinel-garnet transition (2.5–3.5 GPa) close to the amphibole stability limit (~90–110 km and 2.5–3.5 GPa).
226 2 - PublicationRestrictedSr-Nd ISOTOPIC DATA FOR THE CAMPI FLEGREI CALDERA: EVALUATION OF MAGMA DIFFERENTIATION AND CONTRIBUTION TO VOLCANIC HAZARD ASSESSMENT(2007)
; ; ; ; ; ; ; New Sr, Nd, Pb isotopic data, and melt inclusions results are combined with available information on the composition and petrology of the Campi Flegrei erupted volcanic rocks, and with the geophysical structure of the underlying crust to reconstruct the magmatic history and to develop a model for the magmatic processes and structure of the caldera. The results, here briefly summarised, show the important role of the isotopes in defining the temporal evolution of the Campi Flegrei magmatic system, and in predicting its future evolution.50 1 - PublicationOpen AccessRelationship between magmatic processes in the plumbing system of Mt. Etna and the dynamic of the eastern flank: inferences from the petrologic study of the products erupted from 1995 to 2005(2010-07-06)
; ;Civetta, Lucia; ; ;Métrich, Nicole; ;Corsaro, Rosa Anna; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Civetta, Lucia; Università di Napoli Federico II ;Di Renzo, Valeria; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Distefano, Salvatore; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Métrich, Nicole; Laboratoire Pierre Sue, CEA-CNRS ;Miraglia, Lucia; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ;Università di Napoli Federico II; ; ;Laboratoire Pierre Sue, CEA-CNRSThe Team 4 of RU 11 collected, analyzed and interpreted a set of volcanological and petrologic data (petrography, mineral chemistry, major, trace elements, Sr and Nd isotopic compositions and melt inclusions in olivine), concerning the activity and the products erupted by the four summit craters (South-East, North-East, Bocca Nuova and Voragine) of Mt. Etna from 1995 to 2001 and integrated them with petrologic data already available in literature for the flank eruptions occurring from 2001 to 2005.The results of this activity allowed: i) to identify the compositional features of the magmas stored within the shallow (< 5 km b.s.l.) and deep portion (> 5 km b.s.l.) of Mt. Etna plumbing system; ii) to identify and quantify the main magmatic processes (e.g. fractional crystallization, mixing) there occurring; iii) to better constrain the geometry (shape and depth) of Mt. Etna shallow storage zones; iv) to correlate the time related sequence of compositional data with other datasets; v) to infer if a relationship exists between the magmatic processes in the plumbing system of Mt. Etna and the dynamic of the eastern flank.176 46 - PublicationRestrictedA two-component mantle source feeding Mt. Etna magmatism: Insights from the geochemistry of primitive magmas(2014-01)
; ; ; ; ; ; ; ;Correale, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Paonita, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Martelli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Rizzo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Rotolo, S. G.; Dipartimento di Scienze della Terra e del Mare (DiSTeM), Università degli Studi di Palermo ;Corsaro, R. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Di Renzo, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; ; ; Themajor elements, trace elements and Sr and Nd isotopes of selected Etnean primitive rocks (b15 ky BP) were studied in order to characterize their mantle source. The noble-gas geochemistry of fluid inclusions in minerals fromthe same lavaswas also investigated. Themajor element compositions ofwhole rocks and minerals showed that these products are among the most primitive atMt. Etna, comprising 6.3–17.5 wt.% MgO. The variable LREE (Light Rare Earth Elements) enrichment relative to MORB (Mid-Ocean Ridge Basalt) (Lan/Ybn = 11–26), togetherwith the patterns of certain trace-element ratios (i.e., Ce/Yb versus Zr/Nb and Th/Y versus La/Yb), can be attributed to varying degrees of melting of a common mantle source. Numerical simulations performed with the MELTS program allowed the melting percentages associated with each product to be estimated. This led us to recalculate the hypothetical parental trace-element content of the Etneanmantle source, whichwas common to all of the investigated rocks. The characteristics of the Sr, Nd and He isotopes confirmed the primitive nature of the rocks,with themost-depleted and primitive lava being that ofMt. Spagnolo (SPA; 143Nd/144Nd = 0.512908 87Sr/ 86Sr = 0.703317–0.703325 and 3He/4He = 7.6 Ra), and highlighted the similarity of the mantle sources feeding the volcanic activity of Mt. Etna and the Hyblean Plateau (a region to the south of Mt. Etna and characterized by oldermagmatismthan Mt. Etna). The coupling of noble gases and trace elements suggests an origin for the investigated Etnean lavas from melting of a Hyblean-like mantle, consisting of a two-component source where a peridotitic matrix is veined by 10% pyroxenite. A variable degree of mantle contamination by crustal-like fluids, probably related to subduction, is proposed to explain the higher Sr-isotope and lowerNd-isotope values in some rocks (143Nd/144Nd up to 0.512865 and 87Sr/86Sr up to 0.703707). This process probably occurred in the source prior tomagma generation, refertilizing some portions of themantle. Accordingly, the estimated degree of melting responsible for each magma appears to be related to its 87Sr/86Sr enrichment. In contrast, the decoupling between 3He/4He and 87Sr/86Sr ratios requires the occurrence in the crustal reservoirs of further processes capable of shifting the He isotope ratio towards slightly more radiogenic values, such as magma aging or a contribution of shallow fluid. Therefore, different residence times in the Etnean reservoir and/or various rates of magma ascent could be key parameters for preserving the original He isotope marker of the Etnean mantle source.734 58
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