Options
D'Oriano, Claudia
Loading...
Preferred name
D'Oriano, Claudia
Email
claudia.doriano@ingv.it
Staff
staff
ORCID
29 results
Now showing 1 - 10 of 29
- PublicationRestrictedThe Onano eruption (Latera volcano, Central Italy): an example of magma mixing/mingling as dominant process in a caldera-forming eruptionThe Onano eruption (~ 0.17 Ma) is the second to last caldera-forming eruption of the Latera volcano, in the northernmost sector of the Roman Comagmatic Province (Latium, Italy). The stratigraphic sequence, from base to top, includes ash and pumice-rich flow deposits, spatter-rich flow deposits and lag breccias associated with ash-rich flow deposits. By combin-ing major and trace element compositions of the bulk rocks, matrix glasses and minerals of juvenile components from the different depositional units, we reconstruct the pre-eruptive evolution of the magma chamber and the syn-eruptive magma dynamics. Juvenile clasts with heterogeneous glass composition and/or mineral assemblage are a ubiquitous feature of the Onano eruption. The products cover a large compositional range from phonotephrite to phonolite. They are crystal poor, with felsic paragenesis associated to Mg-rich olivine (Fo82–90) and diopside (Fs4–7), these last not in equilibrium with the erupted melts. The mafic mineral assemblage suggests that the pre-eruption magma reservoir was periodically perturbed by the arrival of a primitive magma carrying on Mg-rich minerals and/or remobilizing a mafic crystal mush at the bottom of the reservoir. According to the results obtained from both rhyolite-MELTS and Rayleigh crystal fractionation modeling, we infer that the system evolved from phonotephrite to phonolite both via crystal fractionation and magma mixing between the two end members. Crystallization mostly proceeded at the wall of the reservoir, while magma mixing in the middle zones of the chamber generated the intermediate tephriphonolitic melts. The pre-eruptive chemical zoning was disrupted during the course of the eruption due to the simultaneous withdrawal of magma from different portions of the reservoir. During the first phase of the eruption, high-silica tephriphonolitic to phonolitic melts, residing in the upper part of the reservoir, were emitted with less involvement of the deeper phonotephrite. Phonotephritic magmas, with only a minor contribution of evolved melts, were later erupted as spatter-rich pyroclastic flows that preceded the main caldera collapse. During the caldera collapse, the whole reservoir was involved, leading to extensive and intimate syn-eruption mingling of the different melts. A comparison between the Onano eruption and other eruptions of the Italian high potassic volcanism provides new insights into the evolution of the Roman Comagmatic Province magmas and their eruptive processes.
454 2 - PublicationOpen AccessPetrological monitoring of active volcanoes: A review of existing procedures to achieve best practices and operative protocols during eruptions(2021)
; ; ; ; ; ; ; questionnaire to survey the common petrological monitoring procedures adopted by volcano monitoring insti- tutions has been developed, aimed at identifying prevailing techniques and rating their suitability in terms of costs versus benefits. The collected information resulted from a sample of eighteen participating institutions, which include countries with some of the most important active volcanic provinces worldwide. The participating institutions also offer insights into volcanoes with a variety of volcanic activity, providing a comprehensive pic- ture of the state of art of petrological monitoring. The final purposes are (i) to promote the advancement that pet- rologic monitoring brings in the comprehension of the eruptive processes, providing the only “signals” (i.e., rock samples) concerning the physico-chemical properties of the magma feeding the eruption; (ii) to design best practices, and (iii) to define the minimum requirements needed to perform an efficient petrological monitoring during ongoing eruptions. The survey also highlighted the main problems to overcome to have a profitable pet- rological monitoring infrastructure, including (i) the time required to accomplish both field survey and labora- tory works (sampling, sample preparation, and analyses), (ii) the lack of onsite analytical facilities, (iii) the shortage of qualified staff. Starting from the state of the art of petrological monitoring, how it is performed by the different institutions worldwide, and what participants considered as the major problems, we identified the Best Practices in Petrolog- ical Monitoring as the best compromise between fast and easy analyses and the relevance of the acquired results.415 13 - PublicationRestrictedPast and present mid-intensity explosive eruptions of Italian volcanoes and their impact on human activity(2010)
; ; ; ; ;Cioni, R.; Dip.to Scienze Terra, Università di Cagliari, Cagliari, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa, Pisa, Italy ;Bertagnini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;D'Oriano, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Pompilio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; ; ; Active Italian volcanoes are characterized by a large variability of eruptive mechanisms, from quiet lava effusions to catastrophic ignimbritic eruptions. The impact of volcanic activity, and in particular of explosive activity, is clearly related to the intensity and magnitude of the eruptions, varying from an incidental interference with everyday life up to devastating consequences on civilizations. While the largest events have usually monopolized the interest of volcanologists and historians, the modalities and impact of mid intensity eruptions have not been investigated in so much detail. In addition, the frequency of occurrence of mid intensity eruptions is by far higher than that of the largest events, so making their study of primary importance for the assessment of the impact of volcanic activity on environment and human life. In this paper, case histories of mid-intensity explosive activity at Mt. Vesuvius, Phlegrean Fields, Mt. Etna and Stromboli are presented in order to introduce and discuss the hazard and impact related to this type of activity.409 45 - PublicationOpen AccessGeochemical processes in the roots of the Azores magmatic systems(2024)
; ; ; ; ; The Azores archipelago, situated east of the Mid-Atlantic Ridge, comprises volcanic islands arranged along sub-parallel spreading systems and rests on a thick oceanic crust. Magma is supplied directly from the roots of the volcanic systems. Located at or nearby the boundary between the crust and the mantle, they consist of mafic cumulates and mafic mush layers. This work focuses on tephra samples and a submarine lava younger than 40.000 years, collected from both central volcanoes and fissure zones. Our report details a new dataset of major, trace, and volatile elements analysed in glassy melt inclusions trapped in olivine (Fo75.8–85.6) which are extracted from cumulative bodies at the vicinity of the crust-mantle boundary. Their compositions cover a range from subalkaline to mildly alkaline basalt, and trachybasalt, which match those of Azores lavas. They registered a chemical evolution through fractional crystallisation of olivine alone, as well as olivine and clinopyroxene, as both the FeOt/MgO (1.4–3.1) and CaO/Al2O3 (0.4–1.0) ratios of the melt decrease. Incompatible element ratios of Zr (40–352 ppm), Ba (135–612 ppm), and Rb (5–77 ppm), as compared to Nb (5–82 ppm), exhibit variability within a limited but significant range of values. The ranges in the Nb/Zr, Ba/Nb and Rb/Nb ratios recorded by melt inclusions possibly reveal distinct geochemical sources (at least two), and mixing between partial melts as they move upward. The halogen signature is characteristic of the shallow mantle. The majority of melt inclusions show Cl/K ratio (0.06) similar to E-MORB, although some of them are comparable to N-MORB (Cl/K = 0.03). Their F/Nd ratio may achieve a rather high value (27.8).94 8 - PublicationRestrictedNew findings of Late Glacial Etna pumice fall deposits in NE Sicily and implications for distal tephra correlations in the Mediterranean area(2017)
; ; ; ; ; Pumice fall deposits found in the Nebrodi Mountains and along the Alcantara River, close to the town of Randazzo (NE Sicily), have been studied to derive information about their volcanic source and age. The geochemical Na-alkaline affinity of juvenile products, benmoreite to trachyte, clearly indicates they originated from Etna volcano (Sicily). Major (EMPA) and trace (LA-ICP-MS) element compositional data on matrix glasses indicate that the investigated deposits have a compositional affinity consistent with the tephra deposits of unit D produced by the Ellittico calderaforming eruptions between ca. 17 and 19 cal ka BP. Furthermore, their compositions correspond to the distal tephra equivalent found in some lacustrine and marine cores in Central Italy (Y-1, TM-11), Tyrrhenian Sea (Et-1; MD10α) and Adriatic Sea (Pal94-66-358; Pal94-8-353). We applied the principal components analysis (PCA), a statistical tool able to reduce the variability of a complex system, to compare the compositions of the proximal samples with the possible distal counterparts found in drill cores of the Mediterranean area. On the basis of northward dispersal of the studied deposits and their geochemical features, we suggest they represent a previously unreported sub-Plinian/Plinian eruption of Ellittico volcano producing medial-distal pumice fall deposits in the Nebrodi Mountains and close to Randazzo, named here the D1c layer. The discovery of these deposits helps solve the problem of distal correlations of the northerly dispersed tephra from Etna related to unit D, for which no definitive attribution with proximal units was given in previous studies. The results presented here add to the knowledge of the eruptive history of the volcano and contribute to expanding the proximal geochemical glass dataset for distal tephra correlation in the Mediterranean region during the Late Glacial period.1259 2 - PublicationRestrictedThe onset of an eruption: selective assimilation of hydrothermal minerals during pre-eruptive magma ascent of the 2010 summit eruption of Eyjafjallajökull volcano, Iceland(2016)
; ; ; ; ; ; ; ; ; ;; ; ;The complex processes occurring in the initial phases of an eruption are often recorded in the products of its opening stage,which are usually characterized by small volume and limited dispersal, and thus generally poorly studied. The 2010 eruption of Eyjafjallajökull (Iceland) represents a unique opportunity for these investigations thanks to the good preservation of tephra deposits within the ice/snow pack. A detailed geochemical investigation on the glassy groundmass of single ash clasts disclosed a population of fragmentswith unusual high 87Sr/86Sr (up to 0.70668) for Icelandic magmatism, and anomalous elemental composition with respect to most of the juvenile material of the eruption. This suggests that during its rise, before intruding into the ice cover, magma at a dyke tip selectively assimilated hydrothermal minerals with seawater-related, high-Sr isotopic ratios (zeolites, silica phases, anhydrite) hosted in altered volcanic/epiclastic rocks. According to the observed precursory seismicity, only restricted to few hours before the onset of the eruption, this process could have accompanied subcritical aseismic fracture opening during the days before the eruption, possibly related to stress corrosion-cracking processes, which enhanced the partial dissolution/melting and subsequent selective assimilation of the host rocks.548 1 - PublicationRestrictedIdentifying recycled ash in basaltic eruptions(2014-07-28)
; ; ; ; ;D'Oriano, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Bertagnini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Cioni, R.; Dipartimento di Scienze della Terra, Università di Firenze ;Pompilio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; ; ; Deposits of mid-intensity basaltic explosive eruptions are characterized by the coexistence of different types of juvenile clasts, which show a large variability of external properties and texture, reflecting alternatively the effects of primary processes related to magma storage or ascent, or of syn-eruptive modifications occurred during or immediately after their ejection. If fragments fall back within the crater area before being re-ejected during the ensuing activity, they are subject to thermally- and chemically-induced alterations. These ‘recycled’ clasts can be considered as cognate lithic for the eruption/explosion they derive. Their exact identification has consequences for a correct interpretation of eruption dynamics, with important implications for hazard assessment. On ash erupted during selected basaltic eruptions (at Stromboli, Etna, Vesuvius, Gaua-Vanuatu), we have identified a set of characteristics that can be associated with the occurrence of intra-crater recycling processes, based also on the comparison with results of reheating experiments performed on primary juvenile material, at variable temperature and under different redox conditions.751 63 - PublicationRestrictedXenopumices from the 2011–2012 submarine eruption of El Hierro (Canary Islands, Spain): Constraints on the plumbing system and magma ascent(2012-09-11)
; ; ; ; ; ; ; ; ;Meletlidis, S.; Centro Geofísico de Canarias, Instituto Geográfico Nacional, Santa Cruz de Tenerife, Spain ;Di Roberto, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Pompilio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Bertagnini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Iribarren, I.; Centro Geofísico de Canarias, Instituto Geográfico Nacional, Santa Cruz de Tenerife, Spain ;Felpeto, A.; Centro Geofísico de Canarias, Instituto Geográfico Nacional, Santa Cruz de Tenerife, Spain ;Torres, P. A.; Centro Geofísico de Canarias, Instituto Geográfico Nacional, Santa Cruz de Tenerife, Spain ;D'Oriano, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; ; ; ; ; ; ; Textures, petrography and geochemical compositions of products emitted during the onset of the 2011–2012 submarine eruption (15 October, 2011) off the coast of El Hierro have been investigated to get information on interaction mechanism between the first rising magma and the crust during the onset of the eruption as well as to get information on magma storage and plumbing systems beneath El Hierro volcano. Studied products consist of 5–50 cm bombs with an outer black to greenish, vesicular crust with bulk basanite composition containing pumiceous xenoliths (xenopumices). Our results show that xenopumices are much more heterogeneous that previously observed, since consist of a macro-scale mingling of a gray trachyte and white rhyolite. We interpreted xenopumices as resulting from the interaction (heating) between the basanitic magma feeding the eruption, a stagnant trachytic magma pocket/s and an associated hydrothermally altered halo with rhyolitic composition. Our findings confirm the importance of the study of the early products of an eruption since they can contain crucial information on the plumbing system geometry and the mechanism of magma ascent.719 23 - PublicationRestrictedMagmatic processes revealed by anorthoclase textures and trace element modeling: The case of the Lajes Ignimbrite eruption (Terceira Island, Azores)The Lajes Ignimbrite on Terceira Island (Azores) records the last major pyroclastic density current-forming eruption of Pico Alto Volcano that occurred ca. 21 kyrs ago. This comenditic trachyte ignimbrite contains up to 30 vol% of crystals, mostly anorthoclase. Geochemical investigation of the products collected throughout two key outcrops reveals that major element compositions are poorly variable, whereas trace elements show significant variability, pointing to the presence of a zoned magma reservoir. Thermometry and oxygen fugacity estimations yielded pre-eruptive temperatures of 850-900°C and ∆NNO -2.4 to -1.8. Meltalkali-feldspar hygrometer indicates magmatic H2O contents ranging from 5.8 wt% in the upper part of the reservoir to 3.6 wt% at the bottom, indicating that the magma reservoir (confined at ~4 km depth) was mainly water-undersaturated before the eruption, except for the topmost portion. Two types of anorthoclase crystals were identified. Type 1 crystals show reverse to oscillatory zoning with An contents of 0.4-2.1 mol% and Ba of 200-2000 ppm. They formed in the middle/upper portion of the reservoir, where fractional crystallization processes dominated. Type 2 crystals, mainly present in the less evolved products, are characterized by patchy-zoned cores with large dissolution pockets surrounded by thick oscillatory-zoned rims and show a wide compositional range (An of 0.5-4.7 mol% and Ba of 142-4824 ppm). Their zoning patterns, together with whole-rock and glass compositions of the juvenile clasts, are consistent with the involvement of an anorthoclase-bearing cumulate from the bottom of the reservoir that underwent partial melting. Crystal dissolution was likely induced by the presence of a heat source at depth, without any mass transfer to the eruptible magma as suggested by the lack of petrographic and chemical evidences of mixing between the resident comenditic trachyte and a mafic/intermediate magma. The thermal instability generated convective plumes that were responsible for the admittance of crystals from the cumulate level into the intermediate portions of the magma reservoir and possibly acted as trigger of the explosive eruption.
660 136 - PublicationRestrictedFingerprinting ash deposits of small scale eruptions by their physical and textural features(2008-10-20)
; ; ; ;Cioni, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;D'Oriano, C.; Dipartimento di Scienze della Terra, Università di Cagliari, Cagliari, Italia ;Bertagnini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; ; Correlation of distal ash deposits with their proximal counterparts mainly relies on chemical and mineralogical characterization of bulk rock and matrix glasses. However, the study of juvenile fragments often reveals the heterogeneity in terms of clast shape, external surface, groundmass texture and composition. This is particularly evident in small scale eruptions, characterized by a strong variability in texture and relative abundance of juvenile fragments. This heterogeneity introduces an inherent uncertainty, that makes the compositional data alone inadequate to unequivocally characterize the tephra bed. Pyroclast characteristics, if described and quantified, can represent an additional clue for the correct identification of the tephra. The paper presents morphological, textural and compositional data on the products of an ash eruption from Middle Age activity of Vesuvius, to demonstrate the information that can be extracted from the proposed type of analysis. Juvenile fragments from five ash layers throughout the studied products were randomly hand-picked and fully characterized in terms of external morphology, particle outline parameterization, groundmass texture and glass composition. Statistical analysis of shape parameters characterized groups of fragments that can be compared with the other textural and physical parameters. The main result is that the data do not show important cross-correlation so suggesting that all of these parameters, together with accurate field data are needed for the complete fingerprinting of a tephra bed. We suggest that this approach is especially important for characterizing the products of small scale, compositionally undistinguishable, eruptions and represents the necessary step to deal with before going into more detailed compositional analyses.319 12
- «
- 1 (current)
- 2
- 3
- »